A novel esterase, EstCS1, was isolated from a compost metagenomics library. The EstCS1 protein, which consists of 309 amino acid residues with an anticipated molecular mass of 34 kDa, showed high amino acid sequence identities to predicted esterases and alpha/beta hydrolases (59%) from some cultured bacteria and to predicted lipases/esterases from uncultured bacteria. The phylogenetic analysis suggested that the EstCS1 belongs to the hormone-sensitive lipase family of lipolytic enzyme classification and contains a catalytic triad including Ser155-Asp255-His285. The Ser155 residue of the catalytic triad in the EstCS1 was located in the consensus active-site motif, GXSXG. Besides, a conserved HGGG motif placed in an oxyanion hole of the hormone-sensitive lipase family was discovered, too. The EstCS1 demonstrated the highest activity toward p-nitrophenyl propionate (C3) and caproate (C6) and was normally stable up to 60°C with optimal activity at 50°C. In addition, an optimal activity was observed at pH 8, and the EstCS1 possessed its stability within the pH range between 5 and 10. Interestingly, EstCS1 had an outstanding stability in up to 30% (v/v) organic solvents and activity over 50% in the presence of 50% (v/v) acetone, ethanol, dimethyl sulfoxide (DMSO), and N,N-dimethylformamide. The EstCS1 hydrolyzed sterically hindered tertiary alcohol esters of t-butyl acetate and linalyl acetate. Considering the properties, such as the moderate thermostability, stability against organic solvents, and activity toward esters of tertiary alcohols, the EstCS1 will be worthwhile to be used for organic synthesis and related industrial applications.

中文翻译：

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从堆肥元基因组文库中分离出的新型中度耐高温酯酶的表征。

从堆肥宏基因组学文库中分离出一种新型酯酶EstCS1。EstCS1蛋白由309个氨基酸残基组成，预期分子量为34 kDa，与某些培养细菌的预测酯酶和α/β水解酶（59％）以及未培养细菌的预测脂酶/酯酶具有很高的氨基酸序列同一性。菌。系统发育分析表明，EstCS1属于脂解酶分类的激素敏感脂酶家族，并包含一个催化三联体，包括Ser155-Asp255-His285。EstCS1中催化三联体的Ser155残基位于共有活性位点基序GXSXG中。另外，还发现了位于激素敏感性脂肪酶家族的氧阴离子孔中的保守的HGGG基序。EstCS1表现出对丙酸对硝基苯酯（C3）和己酸酯（C6）最高的活性，通常在高达60°C的温度下稳定，在50°C的温度下具有最佳活性。此外，在pH 8时观察到最佳活性，并且EstCS1在5至10的pH范围内具有稳定性。有趣的是，EstCS1在高达30％（v / v）的有机溶剂中具有出色的稳定性，并且在50℃以上具有活性在50％（v / v）的丙酮，乙醇，二甲基亚砜（DMSO）和N，N-二甲基甲酰胺的存在下，得到5％。EstCS1水解了乙酸叔丁酯和乙酸芳樟酯的位阻叔醇酯。考虑到中等适度的热稳定性，对有机溶剂的稳定性以及对叔醇酯的活性等特性，