
<PAGE>

                                                                     EXHIBIT 3.1




               AMENDED AND RESTATED CERTIFICATE OF INCORPORATION

                                      OF

                                   NNG, INC.

          NNG, Inc., a corporation organized and existing under the laws of the
State of Delaware, hereby certifies as follows:

          1.  The name of the corporation is NNG, Inc. and the date of filing of
its original Certificate of Incorporation with the Secretary of State of
Delaware was January 16, 2001.

          2.  The text of the Certificate of Incorporation as amended or
supplemented heretofore is hereby amended and restated to read in its entirety
as follows:

              "AMENDED AND RESTATED CERTIFICATE OF INCORPORATION

                                      OF

                                   NNG, INC.

          FIRST:  The name of the corporation is NNG, Inc. (the "Corporation").

          SECOND:  The address of the registered office of the Corporation in
the State of Delaware is Corporation Trust Center, 1209 Orange Street, in the
City of Wilmington, County of New Castle. The name and address of the
Corporation's registered agent in the State of Delaware is the Corporation Trust
Company, Corporation Trust Center, 1209 Orange Street, in the City of
Wilmington, County of New Castle, State of Delaware 19801.

          THIRD:  The purpose of the Corporation is to engage in any lawful act
or activity for which corporations may now or hereafter be organized under the
General Corporation Law of the State of Delaware.

          FOURTH:  1.  The total number of shares of stock which the Corporation
shall have authority to issue is Two Hundred Ten Million (210,000,000),
consisting of Two Hundred Million (200,000,000) shares of Common Stock, par
value One Dollar ($1.00) per share (the "Common Stock"), and Ten Million
(10,000,000) shares of Preferred Stock, par value One Dollar ($1.00) per share
(the "Preferred Stock").

          2.  Shares of Preferred Stock may be issued from time to time in one
or more classes or series, each of which class or series shall have such
distinctive designation or title as shall be fixed by resolution of the Board of
Directors of the Corporation (the "Board of Directors") prior
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to the issuance of any shares thereof. Each such class or series of Preferred
Stock shall have such voting powers, full or limited, or no voting powers, and
such preferences and relative, participating, optional or other special rights
and such qualifications, limitations or restrictions thereof, as shall be stated
in such resolution providing for the issuance of such class or series of
Preferred Stock as may be adopted from time to time by the Board of Directors
prior to the issuance of any shares thereof pursuant to the authority hereby
expressly vested in it, all in accordance with the laws of the State of
Delaware. The Board of Directors is further authorized to increase or decrease
(but not below the number of shares of such class or series then outstanding)
the number of shares of any class or series subsequent to the issuance of shares
of that class or series.

          FIFTH:  In furtherance and not in limitation of the powers conferred
by statute and subject to Article Sixth hereof, the Board of Directors is
expressly authorized to adopt, repeal, rescind, alter or amend in any respect
the bylaws of the Corporation (the "Bylaws").

          SIXTH:  Notwithstanding Article Fifth hereof, the Bylaws may be
adopted, repealed, rescinded, altered or amended in any respect by the
stockholders of the Corporation, but only by the affirmative vote of the holders
of not less than eighty percent (80%) of the voting power of all outstanding
shares of Voting Stock (as defined in paragraph (f) of Section 3 of Article
Fourteenth hereof), regardless of class and voting together as a single voting
class and, where such action is proposed by an Interested Stockholder (as
defined in paragraph (d) of Section 3 of Article Fourteenth hereof), or by any
Affiliate or Associate (each as defined in paragraph (g) of Section 3 of Article
Fourteenth hereof) of an Interested Stockholder, including the affirmative vote
of the holders of a majority of the voting power of all outstanding shares of
Voting Stock, regardless of class and voting together as a single voting class,
other than shares held by the Interested Stockholder which proposed (or the
Affiliate or Associate of which proposed) such action, or any Affiliate or
Associate of such Interested Stockholder; provided, however, that where such
                                          --------  -------
action is approved by a majority of the Continuing Directors (as defined in
paragraph (a) of Section 3 of Article Fourteenth hereof), the affirmative vote
of a majority of the voting power of all outstanding shares of Voting Stock,
regardless of class and voting together as a single voting class shall be
required for approval of such action.

          SEVENTH:  The business and affairs of the Corporation shall be managed
by and under the direction of the Board of Directors. Except as may otherwise be
provided pursuant to Section 2 of Article Fourth hereof in connection with
rights to elect additional directors under specified circumstances which may be
granted to the holders of any class or series of Preferred Stock, the exact
number of directors of the Corporation shall be determined from time to time by
a Bylaw or amendment thereto.

          EIGHTH:  The Board of Directors shall be and is divided into three
classes: Class I, Class II and Class III.  The number of directors in each class
shall be the whole number contained in the quotient obtained by dividing the
authorized number of directors by three. If a fraction is also contained in such
quotient, then additional directors shall be apportioned as follows:  if such
fraction is one-third, the additional director shall be a member of Class I; and
if such fraction is two-thirds, one of the additional directors shall be a
member of Class I and the other shall be a member of Class II.  Each director
shall serve for a term ending on the date of the third Annual Meeting of
Stockholders of the Corporation (the "Annual Meeting") following the

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Annual Meeting at which such director was elected; provided, however, that the
                                                   --------  -------
directors first elected to Class I shall serve for a term ending on the date of
the first Annual Meeting next following the end of the calendar year 2000, the
directors first elected to Class II shall serve for a term ending on the date of
the second Annual Meeting next following the end of the calendar year 2000 and
the directors first elected to Class III shall serve for a term ending on the
date of the third Annual Meeting next following the end of the calendar year
2000.

          Notwithstanding the foregoing provisions of this Article Eighth:  each
director shall serve until his successor is elected and qualified or until his
death, resignation or removal; no decrease in the authorized number of directors
shall shorten the term of any incumbent director, and additional directors,
elected pursuant to Section 2 of Article Fourth hereof in connection with rights
to elect such additional directors under specified circumstances which may be
granted to the holders of any class or series of Preferred Stock, shall not be
included in any class, but shall serve for such term or terms and pursuant to
such other provisions as are specified in the resolution of the Board of
Directors establishing such class or series.

          NINTH:  Except as may otherwise be provided pursuant to Section 2 of
Article Fourth hereof in connection with rights to elect additional directors
under specified circumstances which may be granted to the holders of any class
or series of Preferred Stock, newly created directorships resulting from any
increase in the number of directors, or any vacancies on the Board of Directors
resulting from death, resignation, removal or other causes, shall be filled
solely by the affirmative vote of a majority of the remaining directors then in
office, even though less than a quorum of the Board of Directors. Any director
elected in accordance with the preceding sentence shall hold office for the
remainder of the full term of the class of directors in which the new
directorship was created or the vacancy occurred and until such director's
successor shall have been elected and qualified or until such director's death,
resignation or removal, whichever first occurs.

          TENTH:  Except as may otherwise be provided pursuant to Section 2 of
Article Fourth hereof in connection with rights to elect additional directors
under specified circumstances which may be granted to the holders of any class
or series of Preferred Stock, any director may be removed from office only for
cause and only by the affirmative vote of the holders of not less than eighty
percent (80%) of the voting power of all outstanding shares of Voting Stock
entitled to vote in connection with the election of such director, regardless of
class and voting together as a single voting class; provided, however, that
                                                    --------  -------
where such removal is approved by a majority of the Continuing Directors, the
affirmative vote of a majority of the voting power of all outstanding shares of
Voting Stock entitled to vote in connection with the election of such director,
regardless of class and voting together as a single voting class, shall be
required for approval of such removal.

          ELEVENTH:  Any action required or permitted to be taken by the
stockholders of the Corporation must be effected at a duly called Annual Meeting
or at a special meeting of stockholders of the Corporation, unless such action
requiring or permitting shareholder approval is approved by a majority of the
Continuing Directors, in which case such action may be authorized or taken by
the written consent of the holders of outstanding shares of Voting Stock having
not less than the minimum voting power that would be necessary to authorize or
take such action at a meeting of stockholders at which all shares entitled to
vote thereon were present

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and voted, provided all other requirements of applicable law and this Amended
and Restated Certificate have been satisfied.

          TWELFTH:  Special meetings of the stockholders of the Corporation for
any purpose or purposes may be called at any time by a majority of the Board of
Directors or by the Chairman of the Board. Special meetings may not be called by
any other person or persons. Each special meeting shall be held at such date and
time as is requested by the person or persons calling the meeting, within the
limits fixed by law.

          THIRTEENTH:  Meetings of stockholders of the Corporation may be held
within or without the State of Delaware, as the Bylaws may provide. The books of
the Corporation may be kept (subject to any provision of applicable law) outside
the State of Delaware at such place or places as may be designated from time to
time by the Board of Directors or in the Bylaws.

          FOURTEENTH:  1.  Subject to the provisions of Section 2 of this
Article Fourteenth, in addition to any vote required by law, a Business
Combination (as defined in paragraph (b) of Section 3 of this Article
Fourteenth) shall be approved by the affirmative vote of the holders of not less
than:

               (a)  eighty percent (80%) of the voting power of all outstanding
          shares of Voting Stock, regardless of class and voting together as a
          single voting class; and

               (b)  a majority of the voting power of all outstanding shares of
          Voting Stock, other than shares held by any Interested Stockholder
          which is (or the Affiliate or Associate of which is) a party to such
          Business Combination or by any Affiliate or Associate of such
          Interested Stockholder, regardless of class and voting together as a
          single voting class.

          The affirmative votes referred to in paragraphs (a) and (b) of this
Section 1 shall be required notwithstanding the fact that no vote may be
required, or that a lesser percentage or proportion may be specified, by law, or
in any agreement between the Corporation and any national securities exchange or
any other person, or otherwise.

          2.   Notwithstanding the provisions of Section 1 of this Article
Fourteenth, a Business Combination may be approved if all of the conditions
specified in either of the following paragraphs (a) or (b) have been satisfied:

               (a)  both of the following conditions specified in clauses (i)
     and (ii) of this paragraph (a) have been satisfied:

                    (i)  there are one or more Continuing Directors and a
          majority of such Continuing Directors shall have approved such
          Business Combination; and

                    (ii) such Business Combination shall have been approved by
          the affirmative vote of the Corporation's stockholders required by
          law, if any such vote is so required: or

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          (b)  all of the following conditions satisfied in clauses (i) through
     (vii) of this paragraph (b) have been satisfied:

               (i)   such Business Combination shall have been approved by the
          affirmative vote of holders of a majority of the voting power of all
          outstanding shares of Voting Stock, regardless of class and voting
          together as a single voting class;

               (ii)  the aggregate amount of (A) the cash and (B) the Fair
          Market Value (as defined in paragraph (i) of Section 3 of this Article
          Fourteenth), as of the date of the consummation of the Business
          Combination (the "Consummation Date"), of consideration other than
          cash received or to be received, per share, by holders of shares of
          Common Stock in such Business Combination, shall be at least equal to
          the higher of the following:

                     (I)  (if applicable) the highest per share price (including
               any brokerage commissions, transfer taxes and soliciting dealers'
               fees) paid or agreed to be paid by the Interested Stockholder
               which is (or the Affiliate or Associate of which is) a party to
               such Business Combination for any shares of Common Stock (x)
               within the two-year period immediately prior to and including the
               date of the final public announcement of the terms of the
               proposed Business Combination (the "Announcement Date"), or (y)
               in the transaction in which it became an Interested Stockholder,
               whichever is higher; or

                     (II) the Fair Market Value per share of Common Stock (x) on
               the Announcement Date, or (y) on the date on which the Interested
               Stockholder became an Interested Stockholder (the "Determination
               Date"), whichever is higher;

               (iii) the aggregate amount of (A) the cash and (B) the Fair
          Market Value, as of the Consummation Date, of consideration other than
          cash received or to be received, per share, by holders of shares of
          any class of outstanding Voting Stock other than Common Stock in such
          Business Combination, shall be at least equal to the highest of the
          following (it being intended that the requirements of this clause
          (iii) shall be required to be met with respect to every class of
          outstanding Voting Stock other than Common Stock, whether or not such
          Interested Stockholder (or such Affiliate or Associate) has previously
          acquired any shares of a particular class of Voting Stock):

                     (I)  (if applicable) the highest per share price (including
               any brokerage commissions, transfer taxes and soliciting dealers'
               fees) paid or agreed to be paid by the Interested Stockholder for
               any shares of such class of Voting Stock (x) within the two-year
               period immediately prior to the Announcement Date, or (y) in the
               transaction in which it became an Interested Stockholder,
               whichever is higher;

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                     (II)  (if applicable) the highest preferential amount per
               share to which the holders of shares of such class of Voting
               Stock are entitled in the event of any voluntary or involuntary
               liquidation, dissolution or winding up of the Corporation; or

                     (III) the Fair Market Value per share of such class of
               Voting Stock (x) on the Announcement Date, or (y) on the
               Determination Date, whichever is higher;

               (iv)  the consideration to be received by the holders of a
          particular class of outstanding Voting Stock (including Common Stock)
          shall be in cash or in the same form as the Interested Stockholder has
          previously paid (or agreed to pay) for shares of such class of Voting
          Stock; if the Interested Stockholder has paid for shares of any class
          of Voting Stock with varying forms of consideration, the form of
          consideration to be received by holders of shares of such class of
          Voting Stock shall be either cash or the form used to acquire the
          largest number of shares of such class of Voting Stock previously
          acquired by such Interested Stockholder, and the price determined in
          accordance with clauses (ii) and (iii) of this paragraph (b) shall be
          subject to appropriate adjustment in the event of any stock dividend,
          stock split, combination of shares or similar event;

               (v)   after such Interested Stockholder has become an Interested
          Stockholder, and prior to the consummation of such Business
          Combination, neither such Interested Stockholder nor any of its
          Affiliates or Associates shall have become the beneficial owner of any
          additional shares of Voting Stock, except (A) as part of the action
          which resulted in such Interested Stockholder becoming an Interested
          Stockholder, or (B) upon conversion of convertible securities acquired
          by it prior to such Interested Stockholder becoming an Interested
          Stockholder, upon exercise of warrants acquired by it prior to such
          Interested Stockholder becoming an Interested Stockholder, or as a
          result of a stock split or a pro rata stock dividend;

               (vi)  after such Interested Stockholder has become an Interested
          Stockholder, neither such Interested Stockholder nor any of its
          Affiliates or Associates shall have received the benefit, directly or
          indirectly (except proportionately as a stockholder), of any loans,
          advances, guarantees, pledges or other financial assistance or any tax
          credits or other tax advantages provided by the Corporation, whether
          in anticipation of or in connection with such Business Combination or
          otherwise; and

               (vii) a proxy or information statement describing the proposed
          Business Combination and complying with the requirements of the
          Securities Exchange Act of 1934, as amended, and the rules and
          regulations thereunder (or any subsequent provisions replacing such
          Act, rules and/or regulations) shall be mailed to stockholders of the
          Corporation at least thirty (30) days prior to the consummation of
          such Business Combination (whether or not such proxy or

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          information statement is required to be mailed pursuant to such Act,
          rules and/or regulations or such subsequent provisions).

          3.   For the purposes of this Amended and Restated Certificate of
Incorporation, the following definitions shall apply:

          (a)  "Continuing Director" means (i) any member of the Board of
     Directors who (A) is not an Interested Stockholder or an Affiliate or
     Associate of an Interested Stockholder and (B) was a member of the Board of
     Directors prior to the time that an Interested Stockholder became an
     Interested Stockholder, and (ii) any person who is elected or nominated to
     succeed a Continuing Director, or to join the Board of Directors, by a
     majority of the Continuing Directors.

          (b)  "Business Combination" means any one or more of the following
     transactions referred to in clauses (i) through (vi) of this paragraph (b):

               (i)   any merger or consolidation of the Corporation or any
          Subsidiary (as defined in paragraph (h) of this Section 3) with or
          into (A) any Interested Stockholder or (B) any other corporation
          (whether or not itself an Interested Stockholder) which immediately
          before is, or after such merger or consolidation would be, an
          Affiliate or Associate of an Interested Stockholder;

               (ii)  any sale, lease, exchange, mortgage, pledge, transfer or
          other disposition (in one transaction or a series of related
          transactions) to or with any Interested Stockholder, Affiliate and/or
          any Associate of any Interested Stockholder of any assets of the
          Corporation and/or any Subsidiary, where such assets have an aggregate
          Fair Market Value of Twenty-Five Million Dollars ($25,000,000) or
          more;

               (iii) the issuance or transfer by the Corporation and/or any
          Subsidiary (in one transaction or a series of related transactions) of
          any equity securities of the Corporation and/or any Subsidiary to a
          person which, immediately prior to such issuance or transfer, is an
          Interested Stockholder or an Affiliate or Associate of an Interested
          Stockholder, where such equity securities have an aggregate Fair
          Market Value of Ten Million Dollars ($10,000,000) or more;

               (iv)  the adoption of any plan or proposal for the liquidation or
          dissolution of the Corporation;

               (v)   any reclassification of securities (including any reverse
          stock split) or recapitalization of the Corporation, or any merger or
          consolidation of the Corporation with any of its Subsidiaries or any
          similar transaction (whether or not with or into or otherwise
          involving an Interested Stockholder), which has the effect, directly
          or indirectly, of increasing the percentage of the outstanding shares
          of any class of equity or convertible securities of the Corporation or
          any Subsidiary which is directly or indirectly owned by any Interested
          Stockholder or by any Affiliate and/or Associate of any Interested
          Stockholder; or

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               (vi)      any agreement, contract or other arrangement providing
          for any of the transactions described in clauses (i) through (v) of
          this paragraph (b).

          (c)  A "person" means an individual, firm, partnership, trust,
     corporation or other entity.

          (d)  "Interested Stockholder" means any person who or which, together
     with its Affiliates and Associates, as of the record date for the
     determination of stockholders entitled to notice of, and to vote on, any
     Business Combination, the removal of a director or the adoption of any
     proposed amendment, alteration, rescission or repeal of any provision of
     this Amended and Restated Certificate of Incorporation or any Bylaw, or
     immediately prior to the Consummation Date:

               (i)  is the beneficial owner (as defined in paragraph (e) of this
          Section 3), directly or indirectly, of ten percent (10%) or more of
          the voting power of (A) all outstanding shares of Voting Stock or (B)
          all outstanding shares of the capital stock of a Subsidiary having
          general voting power ("Subsidiary Stock"); or

               (ii) is an assignee of or has otherwise succeeded to any share of
          Voting Stock or Subsidiary Stock which was, at any time within the
          two-year period prior thereto, beneficially owned by any person who at
          such time was an Interested Stockholder, and such assignment or
          succession shall have occurred in the course of a transaction or
          series of transactions not involving a public offering within the
          meaning of the Securities Act of 1933, as amended, and the rules and
          regulations thereunder (or any subsequent provisions replacing such
          Act, rules and/or regulations); provided, however, that the term
                                          --------  -------
          "Interested Stockholder" shall not include (A) the Corporation or any
          Subsidiary or (B) any profit-sharing, employee stock ownership or
          other employee benefit plan of the Corporation or any Subsidiary, or
          any trustee of, or fiduciary with respect to, any such plan when
          acting in such capacity.

          (e)  A person is the "beneficial owner" of any shares of capital
               stock:

               (i)   which such person or any of its Affiliates or Associates
          beneficially owns, directly or indirectly;

               (ii)  which such person or any of its Affiliates or Associates
          has (A) the right to acquire (whether such right is exercisable
          immediately or only after the passage of time), pursuant to any
          agreement, arrangement or understanding or upon the exercise of
          conversion rights, exchange rights, warrants or options, or otherwise,
          or (B) the right to vote pursuant to any agreement, arrangement or
          understanding; or

               (iii) which are beneficially owned, directly or indirectly, by
          any other person with which such first-mentioned person or any of its
          Affiliates or Associates has any agreement, arrangement or
          understanding for the purpose of

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          acquiring, holding, voting or disposing of any shares of capital stock
          of the Corporation or a Subsidiary, as the case may be.

          (f) "Voting Stock" means the capital stock of the Corporation having
     general voting power. For the purpose of determining whether a person is an
     Interested Stockholder pursuant to paragraph (d) of this Section 3, the
     number of shares of Voting Stock or Subsidiary Stock, as the case may be,
     deemed to be outstanding shall include shares deemed owned by a beneficial
     owner through application of paragraph (e) of this Section 3, but shall not
     include any other shares of Voting Stock or Subsidiary Stock, as the case
     may be, which may be issuable to any other person pursuant to any
     agreement, arrangement or understanding, or upon exercise of conversion
     rights, warrants or options, or otherwise.

          (g) "Affiliate" and "Associate" have the respective meanings given to
     those terms in Rule 12b-2 of the General Rules and Regulations under the
     Securities Exchange Act of 1934, as amended, as in effect on January 1,
     2001

          (h) "Subsidiary" means any corporation of which a majority of any
     class of equity security (as defined in Rule 3a 11-1 of the General Rules
     and Regulations under the Securities Exchange Act of 1934, as amended, as
     in effect on January 1, 2001) is owned, directly or indirectly, by the
     Corporation.

          (i) "Fair Market Value" means (i) in the case of stock (A) the highest
     closing sale price during the 30-day period including and immediately
     preceding the date in the question of a share of such stock on the
     Composite Tape for New York Stock Exchange-Listed Stocks, or (B) if such
     stock is not quoted on the Composite Tape, the highest closing sale price
     during such 30-day period on the New York Stock Exchange, or (C) if such
     stock is not listed on such Exchange, the highest closing sale price during
     such 30-day period on the principal United States securities exchange
     registered under the Securities Exchange Act of 1934, as amended, on which
     such stock is listed, or (D) if such stock is not listed on any such
     exchange, the highest closing bid quotation with respect to a share of such
     stock on the National Association of Securities Dealers, Inc. Automated
     Quotations System or any system then in use during such 30-day period, or
     (E) if no such quotations are available, the fair market value on the date
     in question of a share of such stock as determined in good faith by a
     majority of the Continuing Directors (or if there are no Continuing
     Directors, then by a majority of the Board of Directors), and (ii) in the
     case of property other than cash or stock, the fair market value of such
     property on the date in question as determined in good faith by a majority
     of the Continuing Directors (or if there are no Continuing Directors, then
     by a majority of the Board of Directors).

          (j) In the event of any Business Combination in which the Corporation
     survives, the phrase "consideration other than cash received or to be
     received" as used in clauses (ii) and (iii) of paragraph (b) of Section 2
     of this Article Fourteenth shall include the shares of Common Stock and/or
     the shares of any other class of Voting Stock retained by the holder of
     such shares.

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          4.  A majority of the Continuing Directors shall have the power and
duty to determine, for purposes of this Article Fourteenth, on the basis of
information known to them:  (a) whether a person is an Interested Stockholder,
(b) the number of shares of Voting Stock or Subsidiary Stock beneficially owned
by any person, (c) whether a person is an Affiliate or Associate of another
person, (d) whether a person has an agreement, arrangement or understanding with
another person as to the matters referred to in clause (vi) of paragraph (b), or
clause (ii) or (iii) of paragraph (e), of Section 3 of this Article Fourteenth,
(e) whether any particular assets of the Corporation and/or any Subsidiary have
an aggregate Fair Market Value of Twenty-Five Million Dollars ($25,000,000) or
more, or (f) whether the consideration received for the issuance or transfer of
securities by the Corporation and/or any Subsidiary has an aggregate Fair Market
Value of Ten Million Dollars ($10,000,000) or more. In furtherance and not in
limitation of the preceding powers and duties set forth in this Section 4, a
majority of the Continuing Directors shall have the power and duty to interpret
all of the terms and provisions of this Article Fourteenth.

          5.  Nothing contained in this Article Fourteenth shall be construed to
relieve any Interested Stockholder or any Affiliate or Associate thereof from
any fiduciary obligation imposed by law.

          6.  The fact that any action or transaction complies with the
provisions of this Article Fourteenth shall not be construed to impose any
fiduciary duty, obligation or responsibility on the Board of Directors or any
member thereof to approve such action or transaction or recommend its adoption
or approval to the stockholders of the Corporation, nor shall such compliance
limit, prohibit or otherwise restrict in any manner the Board of Directors, or
any member thereof, with respect to evaluations of, or actions and responses
taken with respect to, such action or transaction.

          FIFTEENTH:  To the maximum extent permissible under Section 262 of the
General Corporation Law of the State of Delaware, the stockholders of the
Corporation shall be entitled to the statutory appraisal rights provided
therein, notwithstanding any exception otherwise provided therein, with respect
to any Business Combination involving the Corporation and any Interested
Stockholder (or any Affiliate or Associate of any Interested Stockholder), which
requires the affirmative vote specified in paragraph (a) of Section Section I of
Article Fourteenth hereof.

          SIXTEENTH:  The provisions set forth in this Article Sixteenth and in
Articles Fourth, Fifth, Sixth, Seventh, Eighth, Ninth, Tenth, Eleventh, Twelfth,
Fourteenth and Fifteenth hereof may not be repealed, rescinded, altered or
amended in any respect, and no other provision or provisions may be adopted
which impair(s) in any respect the operation or effect of any such provision,
except by the affirmative vote of the holders of not less than eighty percent
(80%) of the voting power of all outstanding shares of Voting Stock regardless
of class and voting together as a single voting class and, where such action is
proposed by an Interested Stockholder or by any Associate or Affiliate of an
Interested Stockholder, the affirmative vote of the holders of a majority of the
voting power of all outstanding shares of Voting Stock, regardless of class and
voting together as a single class, other than shares held by the Interested
Stockholder which proposed (or the Affiliate or Associate of which proposed)
such action, or any Affiliate or Associate of such Interested Stockholder,
provided, however, that where such action is approved
- --------  -------

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by a majority of the Continuing Directors, the affirmative vote of a majority of
the voting power of all outstanding shares of Voting Stock, regardless of class
and voting together as a single voting class, shall be required for approval of
such action.

          SEVENTEENTH:  The Corporation reserves the right to adopt, repeal
rescind, alter or amend in any respect any provision contained in this Amended
and Restated Certificate of Incorporation in the manner now or hereafter
prescribed by applicable law, and all rights conferred on stockholders herein
are granted subject to this reservation. Notwithstanding the preceding sentence,
the provisions set forth in Articles Fourth, Fifth, Sixth, Seventh, Eighth,
Ninth, Tenth, Eleventh, Twelfth, Fourteenth, Fifteenth and Sixteenth may not be
repealed, rescinded, altered or amended in any respect, and no other provision
or provisions may be adopted which impair(s) in any respect the operation or
effect of any such provision, unless such action is approved as specified in
Article Sixteenth hereof.

          EIGHTEENTH:  A director of the Corporation shall not be personally
liable to the Corporation or to its stockholders for monetary damages for breach
of fiduciary duty as a director, except for liability (i) for any breach of the
director's duty of loyalty to the Corporation or to its stockholders, (ii) for
acts or omissions not in good faith or which involve intentional misconduct or a
knowing violation of law, (iii) under Section 174 of the General Corporation Law
of the State of Delaware, or (iv) for any transaction from which the director
derives any improper personal benefit.  If, after approval of this Article by
the stockholders of the Corporation, the General Corporation Law of the State of
Delaware is amended to authorize the further elimination or limitation of the
liability of directors, then the liability of a director of the Corporation
shall be eliminated or limited to the fullest extent permitted by the General
Corporation Law of the State of Delaware, as so amended. Any repeal or
modification of this Article by the stockholders of the Corporation as provided
in Article Seventeen hereof shall not adversely affect any right or protection
of a director of the Corporation existing at the time of such repeal or
modification."

          3.  The amendment and restatement of this Corporation's Certificate of
Incorporation has been approved by this Corporation's Board of Directors and
stockholders and was duly adopted in accordance with the provisions of Sections
242 and 245 of the General Corporation Law of the State of Delaware.

                                       11
<PAGE>

          IN WITNESS WHEREOF, said NNG, Inc. has caused this Certificate to be
signed by Albert F. Myers, its President, and attested by John H. Mullan, its
Secretary, this 31st day of January, 2001.


                                         BY: /s/ ALBERT F. MYERS
                                            __________________________________
                                             Albert F. Myers, President

ATTEST:

BY: /s/ JOHN H. MULLAN
    _______________________________
    John H. Mullan, Secretary
