Section 2. The commissioner shall be appointed by the governor to serve for a term coterminous with that of the governor. The position of commissioner shall be classified in accordance with section forty-five of chapter thirty and the salaries shall be determined in accordance with section forty-six C of said chapter thirty and he shall devote his full time during business hours to the duties of his office. He shall not be an officer of or directly or indirectly interested in any national bank or in any bank, trust company, corporation, business or occupation that requires his official supervision, and he shall not engage in any other business. He shall give bond with sureties in the sum of twenty thousand dollars, to be approved by the state treasurer, for the faithful performance of his duties.