Characterization of a Streptomyces rochei endoglucanase
Characterization of a Streptomyces rochei endoglucanase
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DOI：
10.1111/j.1749-6632.1996.tb40558.x
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发表时间：
1996-01-01
期刊：
影响因子：
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通讯作者：
Mastromei, G
中科院分区：
文献类型：
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作者：
Irdani, T;Perito, B;Mastromei, G
纤维素是世界上最重要的可再生资源之一。将纤维素材料生物转化为有用的产品（燃料和化学品）具有巨大的潜在经济价值，但是，尽管对纤维素酶的酶学进行了广泛的研究，但这些酶的作用模式尚未完全清楚。纤维素水解的基本模型涉及三种主要类型的酶2：内切-1，4-β-葡聚糖酶（EC 3.2。1.4）、纤维二糖水解酶（EC 3.2. 1.91）和β-葡糖苷酶（EC 3.2. 1.21）。里氏木霉被认为是最有效的纤维素降解微生物之一。2无论如何，其纤维素酶的低比活性和缺乏其他生物技术上重要的方面使得寻找新的纤维素分解微生物具有重要意义。纤维素酶基因在非纤维素分解宿主中的克隆使得单纤维素酶的高产和活性研究成为可能。大多数已知的纤维素酶被组织成一个域结构，包括催化域、非催化域和纤维素结合域。根据氨基酸序列的同源性，将它们分为若干科，并对其进化进行了研究。放线菌是参与土壤和堆肥中天然有机基质降解的微生物群落的重要组成部分，并且已经报道了几种菌株的纤维素分解活性。放线菌降解纤维素似乎比真菌降解纤维素受到的生理调节不那么严格，这可能是有利的，再加上大规模培养这些微生物的专业知识。放线菌纤维素酶的生物化学和遗传学研究主要集中在嗜热单孢菌Thermomonospora zyxwvutsrq fusca中。7.8相反，链霉菌纤维素酶的分子遗传学分析很少，尽管有几种遗传操作策略可用于该genus.We正在研究Streptomyces rochei A2，一种分泌能够降解纤维素的酶的纤维素分解放线菌。为了鉴定和分析与纤维素降解相关的基因，我们构建了一个S。rocheiA 2基因组文库中，从中我们分离到一个质粒pCSF 1，它赋予E. coli cclls.”S。罗氏A2内切葡聚糖酶
Cellulose is one of the most important renewable resources in the world. The bioconversion of cellulosic material into useful products (fuels and chemicals) has a great potential economic value, but, despite extensive studies on the enzymology of cellulases, the mode of action of these enzymes is not yet completely clear.'The basic model of cellulose hydrolysis involves three major classes of enzymes2: the endo-1, 4-P-glucanases (EC 3.2. 1.4), the cellobiohydrolases (EC 3.2. 1.91), and the p-glucosidases (EC 3.2. 1.21). The mold Trichoderma reesei is considered one of the most effective cellulose-degrading microorganisms. 2 At any rate, the low specific activity and the lack of other biotechnologically important aspects of its cellulases give importance to the search for new cellulolytic microorganism^.^ The cloning of cellulase genes in noncellulolytic hosts has allowed the hyperproduction and study of single cellulase activities. Most of the known cellulases are organized into a domain structure including catalytic, noncatalytic and cellulosebinding domains. On the basis of amino acid sequence homology, they have been classified into a number of families and their evolution~ tudied.~ Actinomycetes constitute an important part of the microbial community involved in natural organic substrate degradation in soils and composts, and cellulolytic activity has been reported in several strains.'Cellulose degradation by actinomycetes seems to be subject to less stringent physiological regulation than in fungi, h and this could be advantageous, together with the expertise available in large-scale cultivation of these microorganisms. The biochemistq and genetics of actinomycete cellulases has mainly been studied in the thermophilic species Thermomonospora zyxwvutsrq fusca. 7.8 In contrast, there has been little molecular genetic analysis of Streptomyces cellulases, although several genetic manipulation strategies for this genus are available.We arc working on Streptomyces rochei A2, a cellulolytic actinomyccte that secretes enzymes capable of degrading cellulose. In order to identify and analyze the genes involved in cellulose degradation, we constructed a S. rochei A2 genomic bank in the Escherichia coli vector pAT153 from which we isolated a plasmid, pCSF1, that conferred endoglucanase activity on E. coli cclls.'The S. rochei A2 endoglucanase