Traffic Jams Reduce Hydrolytic Efficiency of Cellulase on Cellulose Surface
Traffic Jams Reduce Hydrolytic Efficiency of Cellulase on Cellulose Surface
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DOI：
10.1126/science.1208386
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发表时间：
2011-09-02
期刊：
影响因子：
56.9
通讯作者：
Samejima, Masahiro
中科院分区：
文献类型：
--
作者：
Igarashi, Kiyohiko;Uchihashi, Takayuki;Samejima, Masahiro
深入了解纤维素生物质的糖化机理可以提高生物燃料开发的效率。我们在这里报告的实时可视化的结晶纤维素降解的纤维素酶通过使用先进版本的高速原子力显微镜。观察到里氏木霉纤维二糖水解酶I（TrCel7A）分子沿结晶纤维素表面单向沿着滑动，但在一点处表现出类似于交通堵塞的集体停顿。通过氨处理改变纤维素的结晶多晶型形式增加了结晶表面上可接近泳道的表观数量，从而增加了移动纤维素酶分子的数量。同时或分别用T. reesei纤维二糖水解酶II（TrCel6A）导致表面上移动的酶分子的比例显著增加。在两种酶的协同作用下，纤维素被完全降解。
A deeper mechanistic understanding of the saccharification of cellulosic biomass could enhance the efficiency of biofuels development. We report here the real-time visualization of crystalline cellulose degradation by individual cellulase enzymes through use of an advanced version of high-speed atomic force microscopy. Trichoderma reesei cellobiohydrolase I (TrCel7A) molecules were observed to slide unidirectionally along the crystalline cellulose surface but at one point exhibited collective halting analogous to a traffic jam. Changing the crystalline polymorphic form of cellulose by means of an ammonia treatment increased the apparent number of accessible lanes on the crystalline surface and consequently the number of moving cellulase molecules. Treatment of this bulky crystalline cellulose simultaneously or separately with T. reesei cellobiohydrolase II (TrCel6A) resulted in a remarkable increase in the proportion of mobile enzyme molecules on the surface. Cellulose was completely degraded by the synergistic action between the two enzymes.