Characterization of an exo-β-1,3-D-galactanase from Streptomyces avermitilis NBRC14893 acting on arabinogalactan-proteins
Characterization of an exo-β-1,3-D-galactanase from Streptomyces avermitilis NBRC14893 acting on arabinogalactan-proteins
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DOI：
10.1271/bbb.60365
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发表时间：
2006-11-01
影响因子：
1.6
通讯作者：
Kaneko, Satoshi
中科院分区：
文献类型：
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作者：
Ichinose, Hitomi;Kotake, Toshihisa;Kaneko, Satoshi
从阿维链霉菌NBRC14893中分离到一个属于糖苷水解酶家族43(GH43)的基因。该基因编码一个由N-端的GH43模块和C-端的13族碳水化合物结合模块组成的模块化蛋白。在大肠杆菌中表达了与GH43模块对应的基因，并对基因产物进行了鉴定。该重组酶仅对底物非还原末端的两个D-半乳糖基残基的β-1，3-键进行了特异性的水解。对水解物的分析表明，该酶以外切方式由β-1，3-D-半乳糖生成半乳糖。当该酶催化阿拉伯半乳糖蛋白的水解时，该酶与半乳糖一起产生低聚糖，这表明该酶能够容纳β-1，6-连接的D-半乳糖侧链。这些性质与以前报道的其他外β-1，3-D-半乳糖苷酶相同。因此，我们得出结论，该分离基因确实编码外β-1，3-D-半乳糖苷酶。这是首次从放线菌中分离到外β-1，3-D-半乳糖苷酶。
A gene belonging to glycoside hydrolase family 43 (GH43) was isolated from Streptomyces avermitilis NBRC14893. The gene encodes a modular protein consisting of N-terminal GH43 module and a family 13 carbohydrate-binding module at the C-terminus. The gene corresponding to the GH43 module was expressed in Escherichia coli, and the gene product was characterized. The recombinant enzyme specifically hydrolyzed only beta-1,3-linkage Of two D-galactosyl residues at non-reducing ends of the substrates. The analysis of the hydrolysis products indicated that the enzyme produced galactose from beta-1,3-D-galactan in an exoacting manner. When the enzyme catalyze hydrolysis of the arabinogalactan-protein, the enzyme produced oligosaccharides together with, galactose, suggesting that the enzyme is able to accommodate beta-1,6-linked D-galactosyl side chains. These properties are the same as the other previously reported exo-beta-1,3-D-galactanases. Therefore, we concluded the isolated gene certainly encodes an exo-beta-1,3-D-galactanase. This is the first report of exo-beta-1,3-D-galactanase from actinomycetes.