title: Improving the thermostability of a methyl parathion hydrolase by adding the ionic bond on protein surface.
abstract: The thermostability of the methyl parathion hydrolase (MPH_OCH) from Ochrobactrum sp. M231 was improved using site-directed mutagenesis. Two prolines (Pro76 and Pro78) located on the protein surface were selected for mutations after inspection of the sequence alignment of MPH_OCH and OPHC2, a thermostable organophosphorus hydrolase from Pseudomonas pseudoalcaligenes C2-1. The temperature of the double-point mutant (P76D/P78K) at which the mutant lost 50% of its activity (T50) was approximately 68 °C, which is higher than that of WT enzyme (64 °C), P76D (67 °C), and P78K (59 °C). Structural analysis of P76D/P78K indicated that the substituted residues (Asp76 and Lys78) could generate an ionic bond and increase the structural electrostatic energy, which could then increase the stability of the protein. These results also suggest that the thermal stability of proteins could be improved by adding the ionic bond on protein surface.
authors: Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, People's Republic of China.
authors: Yidan
authors: Y
authors: Su
authors: Jian
authors: J
authors: Tian
authors: Ping
authors: P
authors: Wang
authors: Xiaoyu
authors: X
authors: Chu
authors: Guoan
authors: G
authors: Liu
authors: Ningfeng
authors: N
authors: Wu
authors: Yunliu
authors: Y
authors: Fan
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D004795:Enzyme Stability; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D006867:Hydrolases / Q000235:genetics / Q000378:metabolism*; D007306:Insecticides / Q000378:metabolism; D007700:Kinetics; D008743:Methyl Parathion / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D042041:Ochrobactrum / Q000201:enzymology* / Q000235:genetics; D010957:Plasmids; D011487:Protein Conformation; D015202:Protein Engineering / Q000379:methods*; D044205:Pseudomonas pseudoalcaligenes / Q000201:enzymology* / Q000235:genetics; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D055672:Static Electricity; D013696:Temperature; D014169:Transformation, Bacterial
chemical_list: D001426:Bacterial Proteins; D007306:Insecticides; D011994:Recombinant Proteins; D008743:Methyl Parathion; D006867:Hydrolases