Molecular identification of Sphingomonas sp. A1 alginate lyase (A1-IV') as a member of novel polysaccharide lyase family 15 and implications in alginate lyase evolution |
| |
Authors: | Hashimoto Wataru Miyake Osamu Ochiai Akihito Murata Kousaku |
| |
Affiliation: | Laboratory of Basic and Applied Molecular Biotechnology, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011, Japan. |
| |
Abstract: | Sphingomonas sp. A1 (strain A1) produces three endotypes (A1-I 65 kDa], A1-II 25 kDa], and A1-III 40 kDa]) and an exotype (A1-IV 86 kDa]) alginate lyases in cytoplasm. These four enzymes cooperatively depolymerize alginate into constituent monosaccharides. In addition to the genes for these lyases, novel genes encoding hypothetical proteins homologous with A1-IV were found in the genomes of many bacteria including strain A1. One such protein, A1-IV' (90 kDa) of strain A1, was overexpressed in Escherichia coli cells, purified, and characterized. A1-IV' catalyzed the cleavage of glycosidic bonds in alginate through a beta-elimination reaction and released unsaturated di- and trisaccharides as main products, thus indicating that the enzyme is an endotype alginate lyase. A1-IV', which differed from A1-IV in some enzymatic properties, was not expressed in strain A1, suggesting that A1-IV' has no significant role in alginate metabolism. A1-IV' and other A1-IV homologs facilitate the creation of novel polysaccharide lyase family 15 based on their primary structures, implying the evolution route of alginate lyases in family PL-15. |
| |
Keywords: | |
本文献已被 PubMed 等数据库收录! |
|