Kieler Wirkstoff-Zentrum am IFM-GEOMAR, Am Kiel Kanal 44, D-24106 Kiel, Germany.
Microbiol Res. 2012 May 20;167(5):262-9. doi: 10.1016/j.micres.2011.11.001. Epub 2011 Dec 7.
This is the first description of a functional chitinase gene within the crenarchaeotes. Here we report of the heterologues expression of the ORF BAB65950 from Sulfolobus tokodaii in E. coli. The resulting protein degraded chitin and was hence classified as chitinase (EC 3.2.4.14). The protein characterization revealed a specific activity of 75 mU/mg using colloidal chitin as substrate. The optimal activity of the enzyme was measured at pH 2.5 and 70°C, respectively. A dimeric enzyme configuration is proposed. According to amino acid sequence similarities chitinases are attributed to the two glycoside hydrolase families 18 and 19. The derived amino acid sequence of the S. tokodaii gene differed from sequences of these two glycoside hydrolase families. However, within a phylogenetic tree of protein sequences, the crenarchaeal sequence of S. tokodaii clustered in close proximity to members of the glycoside hydrolase family 18.
这是在泉古菌门中首次对功能性几丁质酶基因的描述。本文报道了从嗜热硫磺酸菌中异源表达的 ORF BAB65950。所得蛋白可降解几丁质，因此被归类为几丁质酶（EC 3.2.4.14）。该蛋白的特性分析显示，以胶体几丁质为底物时，其比活为 75 mU/mg。该酶的最适活性分别在 pH 2.5 和 70°C 下进行测量。提出了一种二聚体酶构象。根据氨基酸序列相似性，几丁质酶被归入糖苷水解酶家族 18 和 19。嗜热硫磺酸菌基因的推导氨基酸序列与这两个糖苷水解酶家族的序列不同。然而，在蛋白序列的系统发育树中，泉古菌的序列与糖苷水解酶家族 18 的成员紧密聚类。
