The Attorney General is authorized to appear for the state and prosecute and defend, in any court or before any officer, board or tribunal, any cause or matter, civil or criminal, in which the state may be a party or interested. If the Director-State Engineer shall have drawn any plans or specifications for the construction of bridges or other public structures for any county in this state, and such plans shall have been adopted by any such county and bids let thereon, and the same constructed by any person, corporation or association, and suit is brought against such county, person, corporation or association for damages on account of the infringement of any alleged United States patent, in any court, state or federal, it shall be the duty of the Attorney General to intervene in said suit in behalf of the state and defend it, or, if intervention cannot be had, then the Attorney General shall take charge of the suit for such county, person, corporation or association, and defend it, or he may employ counsel to do so, and the fee of such counsel and other expenses shall be paid from appropriations made to the office of the Attorney General.