title: Identification and Characterization of a New Alkaline SGNH Hydrolase from a Thermophilic Bacterium Bacillus sp. K91.
abstract: est19 is a gene from Bacillus sp. K91 that encodes a new esterase. A comparison of the amino acid sequence showed that Est19 has typical Ser-Gly-Asn-His (SGNH) family motifs and could be grouped into the SGNH hydrolase family. The Est19 protein was functionally cloned, and expressed and purified from Escherichia coli BL21(DE3). The enzyme activity was optimal at 60°C and pH 9.0, and displayed esterase activity towards esters with short-chain acyl esters (C₂-C₆). A structural model of Est19 was constructed using phospholipase A1 from Streptomyces albidoflavus NA297 as a template. The structure showed an α/β-hydrolase fold and indicated the presence of the typical catalytic triad Ser49-Asp227-His230, which were further investigated by site-directed mutagenesis. To the best of our knowledge, Est19 is a new member of the SGNH hydrolase family identified from thermophiles, which may be applicable in the industrial production of semisynthetic β-lactam antibiotics after modification.
authors.affiliation: Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Yunnan Normal University, Kunming 650500, P.R. China.
authors.forename: Tingting
authors.initials: T
authors.lastname: Yu
authors.affiliation: Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Yunnan Normal University, Kunming 650500, P.R. China.
authors.forename: Junmei
authors.initials: J
authors.lastname: Ding
authors.affiliation: Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Yunnan Normal University, Kunming 650500, P.R. China.
authors.forename: Qingxia
authors.initials: Q
authors.lastname: Zheng
authors.affiliation: Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Yunnan Normal University, Kunming 650500, P.R. China.
authors.forename: Nanyu
authors.initials: N
authors.lastname: Han
authors.affiliation: Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Yunnan Normal University, Kunming 650500, P.R. China.
authors.forename: Jialin
authors.initials: J
authors.lastname: Yu
authors.affiliation: Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Yunnan Normal University, Kunming 650500, P.R. China.
authors.forename: Yunjuan
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Yunnan Normal University, Kunming 650500, P.R. China.
authors.forename: Junjun
authors.initials: J
authors.lastname: Li
authors.affiliation: Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Yunnan Normal University, Kunming 650500, P.R. China.
authors.forename: Yuelin
authors.initials: Y
authors.lastname: Mu
authors.affiliation: Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Yunnan Normal University, Kunming 650500, P.R. China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Wu
authors.affiliation: Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Yunnan Normal University, Kunming 650500, P.R. China.
authors.forename: Zunxi
authors.initials: Z
authors.lastname: Huang
mesh_terms: D000595:Amino Acid Sequence; D001407:Bacillus / Q000201:enzymology* / Q000235:genetics* / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D020134:Catalytic Domain; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics; D004950:Esterases / Q000235:genetics / Q000378:metabolism; D016680:Genome, Bacterial; D006863:Hydrogen-Ion Concentration; D006867:Hydrolases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D054466:Phospholipases A1 / Q000737:chemistry; D017510:Protein Folding; D013302:Streptomyces / Q000235:genetics; D013379:Substrate Specificity
chemical_list: D001426:Bacterial Proteins; D006867:Hydrolases; D004950:Esterases; D054466:Phospholipases A1
keywords: Bacillus sp. K91; SGNH hydrolase; esterase; heterologous expression; site-directed mutagenesis