State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
J Microbiol Biotechnol. 2010 Apr;20(4):670-7. doi: 10.4014/jmb.0911.11019.
An alkaline pectate lyase, Bsp165PelA, was purified to homogeneity from the culture broth of alkaliphilic Bacillus sp. N16-5. The enzyme showed a specific activity as high as 1000 U/mg and had optimum activity at pH 11.5 and 50 degrees . It was composed of a single polypeptide chain with a molecular of 42 kDa deduced from SDS-PAGE, and its isoelectric point was around pH 6.0. It could efficiently depolymerize polygalacturonate and pectin. Characterization of product formation revealed unsaturated digalacturonate and trigalacturonate as the main product. The pectate lyase gene (pelA) contained an open reading frame (ORF) of 1089 bp, encoding a 36-amino acids signal peptide and a mature protein of 326 amino acids with a calculated molecular mass of 35.943 Da. The deduced amino acid sequence from the pelA ORF exhibited significant homology to those of known pectate lyases in polysaccharide lyase family 1. Some conserved active-site amino acids were found in the deduced amino acid sequence of Bsp165PelA. Ca2+ was not required for activity on pectic substrates.
从嗜碱芽孢杆菌 N16-5 的发酵液中纯化得到一种碱性果胶裂解酶，Bsp165PelA。该酶的比活高达 1000 U/mg，最适 pH 值和温度分别为 11.5 和 50 摄氏度。SDS-PAGE 结果表明，该酶由一条分子量为 42 kDa 的多肽链组成，等电点约为 pH 6.0。它可以有效地降解聚半乳糖醛酸和果胶。产物分析表明，该酶的主要产物为不饱和二糖醛酸和三糖醛酸。果胶裂解酶基因（pelA）包含一个 1089 bp 的开放阅读框（ORF），编码一个 36 个氨基酸的信号肽和一个 326 个氨基酸的成熟蛋白，预测分子量为 35.943 Da。从 pelA ORF 推导的氨基酸序列与多糖裂解酶家族 1 中已知的果胶裂解酶具有显著的同源性。在 Bsp165PelA 的推导氨基酸序列中发现了一些保守的活性位点氨基酸。该酶在果胶底物上的活性不需要 Ca2+。
