tailieunhanh - Báo cáo khoa học: Enhanced thermostability of methyl parathion hydrolase from Ochrobactrum sp. M231 by rational engineering of a glycine to proline mutation

Protein thermostability can be increased by some glycine to proline muta-tions in a target protein. However, not all glycine to proline mutations can improve protein thermostability, and this method is suitable only at care-fully selected mutation sites that can accommodate structural stabilization. | ỊFEBS Journal Enhanced thermostability of methyl parathion hydrolase from Ochrobactrum sp. M231 by rational engineering of a glycine to proline mutation Jian Tian Ping Wang Shan Gao Xiaoyu Chu Ningfeng Wu and Yunliu Fan Biotechnology Research Institute Chinese Academy of AgriculturalSciences Beijing China Keywords methylparathion hydrolase molecular dynamics proline theory thermostability Correspondence Ningfeng Wu Biotechnology Research Institute Chinese Academy of Agricultural Sciences 12 Zhongguancun South Street Beijing 100081 China Fax 86 10 821 09844 Tel. 86 10 821 09844 E-mail wunf@ Received 13 September 2010 revised 25 September 2010 accepted 27 September 2010 doi Protein thermostability can be increased by some glycine to proline mutations in a target protein. However not all glycine to proline mutations can improve protein thermostability and this method is suitable only at carefully selected mutation sites that can accommodate structural stabilization. In this study homology modeling and molecular dynamics simulations were used to select appropriate glycine to proline mutations to improve protein thermostability and the effect of the selected mutations was proved by the experiments. The structure of methyl parathion hydrolase MPH from Ochrobactrum sp. M231 Ochr-MPH was constructed by homology modeling and molecular dynamics simulations were performed on the modeled structure. A profile of the root mean square fluctuations of Ochr-MPH was calculated at the nanosecond timescale and an eight-amino acid loop region residues 186-193 was identified as having high conformational fluctuation. The two glycines nearest to this region were selected as mutation targets that might affect protein flexibility in the vicinity. The structures and conformational fluctuations of two single mutants G194P and G198P and one double mutant G194P G198P were modeled and analyzed using molecular dynamics simulations. The results .