title: Characterization of EstB, a novel cold-active and organic solvent-tolerant esterase from marine microorganism Alcanivorax dieselolei B-5(T).
abstract: A novel esterase gene, estB, was cloned from the marine microorganism Alcanivorax dieselolei B-5(T) and overexpressed in E. coli DE3 (BL21). The expressed protein EstB with a predicted molecular weight of 45.1 kDa had a distinct catalytic triad (Ser(211)-Trp(353)-Gln(385)) and the classical consensus motif conserved in most lipases and esterases Gly(209)-X-Ser(211)-X-Gly(213). EstB showed very low similarity to any known proteins and displayed the highest similarity to the hypothetical protein (46%) from Rhodococcus jostii RHA1. EstB showed the optimal activity around pH 8.5 and 20 °C and was identified to be extremely cold-adaptative retaining more than 95% activity between 0 and 10 °C. The values of kinetic parameters on p-NP caproate (K m, K cat and K cat/K m) were 0.15 mM, 0.54 × 10(3) s(-1) and 3.6 × 10(3) s(-1) mM(-1), respectively. In addition, EstB showed remarkable stability in several studied organic solvents and detergents of high concentrations with the retention of more than 70% activity after treatment for 30 min. The cold activity and its tolerance towards organic solvents made it a promising biocatalyst for industrial applications under extreme conditions.
authors: State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China.
authors: Shanshan
authors: S
authors: Zhang
authors: Guojie
authors: G
authors: Wu
authors: Zhixiang
authors: Z
authors: Liu
authors: Zongze
authors: Z
authors: Shao
authors: Ziduo
authors: Z
authors: Liu
mesh_terms: D000222:Adaptation, Physiological; D053521:Alcanivoraceae / Q000201:enzymology* / Q000235:genetics; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D003080:Cold Temperature; D004950:Esterases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary
chemical_list: D001426:Bacterial Proteins; D004950:Esterases