The unusual cellulose utilization system of the aerobic soil bacterium Cytophaga hutchinsonii
The unusual cellulose utilization system of the aerobic soil bacterium Cytophaga hutchinsonii
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DOI：
10.1007/s00253-017-8467-2
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发表时间：
2017-08
影响因子：
5
通讯作者：
Yongtao Zhu;M. McBride
中科院分区：
文献类型：
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作者：
Yongtao Zhu;M. McBride
纤维素分解微生物在全球碳循环中扮演着重要的角色，并进化出了不同的消化纤维素的策略。有些人“很慷慨”，从细胞外释放纤维素中的可溶性糖，以满足自己和邻居的需求。滑行土壤细菌--HutchinsoniiCytophaga hutchinsoni显示出一种更“自私”的策略。它使用与细胞相关的纤维素酶来消化结晶纤维素，并在细胞外释放很少的可溶性糖。Fc的作用机制。胡萝卜纤维素的利用仍然知之甚少。在这篇综述中，我们讨论了C的新奇方面。HUTCHINSONIICAL纤维素分解系统。最近开发的基因操作工具使识别所涉及的蛋白质成为可能。胡麻纤维的利用。这些包括周质和细胞表面的内切葡聚糖酶和新的纤维素结合蛋白。最近发现的IX型分泌系统是利用纤维素所必需的，似乎可以将一些纤维素酶和其他蛋白质输送到细胞表面。利用纤维素需要周质内切葡聚糖酶，这是不寻常的，这表明在进一步消化之前，必须通过外膜输入纤维低聚物。在许多其他纤维素分解细菌中扮演重要角色的纤维生物水解酶或其他预测的过程性纤维素酶似乎没有出现。哈钦森。细胞OFC。它们附着在纤维素纤维上并沿着纤维滑动，这可能会让它们找到最容易受到攻击的地方。足球俱乐部的模特儿。总结了近年来的研究进展，提出了胡麻纤维素的利用途径。
Cellulolytic microorganisms play important roles in global carbon cycling and have evolved diverse strategies to digest cellulose. Some are ‘generous,’ releasing soluble sugars from cellulose extracellularly to feed both themselves and their neighbors. The gliding soil bacteriumCytophaga hutchinsoniiexhibits a more ‘selfish’ strategy. It digests crystalline cellulose using cell-associated cellulases and releases little soluble sugar outside of the cell. The mechanism ofC. hutchinsoniicellulose utilization is still poorly understood. In this review, we discuss novel aspects of theC. hutchinsoniicellulolytic system. Recently developed genetic manipulation tools allowed the identification of proteins involved inC. hutchinsoniicellulose utilization. These include periplasmic and cell-surface endoglucanases and novel cellulose-binding proteins. The recently discovered type IX secretion system is needed for cellulose utilization and appears to deliver some of the cellulolytic enzymes and other proteins to the cell surface. The requirement for periplasmic endoglucanases for cellulose utilization is unusual and suggests that cello-oligomers must be imported across the outer membrane before being further digested. Cellobiohydrolases or other predicted processive cellulases that play important roles in many other cellulolytic bacteria appear to be absent inC. hutchinsonii. Cells ofC. hutchinsoniiattach to and glide along cellulose fibers, which may allow them to find sites most amenable to attack. A model ofC. hutchinsoniicellulose utilization summarizing recent progress is proposed.