Cellobiohydrolases: Role, Mechanism, and Recent Developments
Cellobiohydrolases: Role, Mechanism, and Recent Developments
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DOI：
10.1007/978-3-319-43679-1_2
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发表时间：
2016-01-01
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影响因子：
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通讯作者：
Sivakumar, Nallusamy
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作者：
Annamalai, Neelamegam;Rajeswari, Mayavan Veeramuthu;Sivakumar, Nallusamy
纤维生物水解酶或外切葡聚糖酶是由多种细菌和真菌产生的，其催化模块属于5、6、7、9、48和74家族糖苷水解酶，它们作用于纤维素链的末端，导致葡萄糖和纤维二糖的释放。Cbh I和Cbh II分别从纤维素链的还原和非还原末端依次起作用。CBHS的催化模块是由两个可能覆盖全部或部分活性中心的表面环形成的隧道结构，证明了随着纤维素酶沿着纤维素链的推进，作用方式是以一种过程的方式进行的。CBHS能够在纤维素的结晶区积极工作，可能会将它们从Avicel的微晶结构中剥离。虽然已经提出了几种方法，但到目前为止还没有描述过测定外切葡聚糖酶的特定底物和测定方法。近年来，为了提高CBHS的活性和稳定性，人们开发了几种新的方法，如Delta序列介导的整合、SCHEMA、FoldX和“共识”序列。
Cellobiohydrolases or exoglucanases are produced by various bacteria and fungi with catalytic modules belonging to families 5, 6, 7, 9, 48, and 74 glycoside hydrolases, which act at the chains end of cellulose resulting in release of glucose as well as cellobiose. The CBH I and II works processively from reducing and nonreducing ends of the cellulose chain, respectively. The catalytic module of CBHs is the tunnel structure formed by two surface loops that may covers entirety or part of active site evidenced that the mode of action proceeds in a processive manner as cellobiohydrolase progresses along the cellulose chain. CBHs are able to work actively in the crystalline region of cellulose, probably peeling them from the microcrystalline structure of Avicel. Although several assays have been proposed, no specific substrate as well as assay method to measure exoglucanases has been described till date. In recent days, several new approaches such as delta-sequence mediated integration, SCHEMA, and FoldX and a 'consensus' sequence have been developed to improve activity and stability of CBHs.