Promotion of Efficient Saccharification of Crystalline Cellulose by Aspergillus fumigatus Swo1
Promotion of Efficient Saccharification of Crystalline Cellulose by Aspergillus fumigatus Swo1
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DOI：
10.1128/aem.02499-09
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发表时间：
2010-04-01
影响因子：
4.4
通讯作者：
Kitamoto, Katsuhiko
中科院分区：
文献类型：
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作者：
Chen, Xin-ai;Ishida, Nobuhiro;Kitamoto, Katsuhiko
Swollenin是里氏木霉的一种蛋白质，具有独特的分解纤维素物质的活性，它与Expansins具有相似的序列，Expansins是一种具有松弛作用的植物细胞壁蛋白，导致细胞壁扩大。在本研究中，我们从丝状真菌烟曲霉中克隆了一个编码类肿胀蛋白Swo1的基因，并将其命名为Afswo1。AfSwo1具有由糖结合模块家族1(CBM1)结构域和植物Expansin样结构域组成的双峰结构。利用米曲霉异源表达产生AfSwo1，利用纤维素亲和层析分离纯化。AfSwo1对羧甲基纤维素(CMC)表现出弱的内切葡聚糖酶活性，不仅与结晶纤维素Avicel结合，而且与甲壳素结合，而与木聚糖没有明显的亲和力。AfSwo1处理导致Avicel分裂成更小的颗粒，没有检测到任何可检测到的还原糖。此外，AFSwo1与纤维素酶混合物同时孵育促进了Avicel的糖化。我们的结果为利用纤维素破坏蛋白AfSwo1将结晶纤维素有效地生物转化为葡萄糖提供了一种新的方法。
Swollenin is a protein from Trichoderma reesei that has a unique activity for disrupting cellulosic materials, and it has sequence similarity to expansins, plant cell wall proteins that have a loosening effect that leads to cell wall enlargement. In this study we cloned a gene encoding a swollenin-like protein, Swo1, from the filamentous fungus Aspergillus fumigatus, and designated the gene Afswo1. AfSwo1 has a bimodular structure composed of a carbohydrate-binding module family 1 (CBM1) domain and a plant expansin-like domain. AfSwo1 was produced using Aspergillus oryzae for heterologous expression and was easily isolated by cellulose-affinity chromatography. AfSwo1 exhibited weak endoglucanase activity toward carboxymethyl cellulose (CMC) and bound not only to crystalline cellulose Avicel but also to chitin, while showing no detectable affinity to xylan. Treatment by AfSwo1 caused disruption of Avicel into smaller particles without any detectable reducing sugar. Furthermore, simultaneous incubation of AfSwo1 with a cellulase mixture facilitated saccharification of Avicel. Our results provide a novel approach for efficient bioconversion of crystalline cellulose into glucose by use of the cellulose-disrupting protein AfSwo1.