Insights into the oxidative degradation of cellulose by a copper metalloenzyme that exploits biomass components
Insights into the oxidative degradation of cellulose by a copper metalloenzyme that exploits biomass components
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DOI：
10.1073/pnas.1105776108
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发表时间：
2011-09-13
影响因子：
11.1
通讯作者：
Walton, Paul H.
中科院分区：
文献类型：
--
作者：
Quinlan, R. Jason;Sweeney, Matt D.;Walton, Paul H.
柑橘类植物生物质的酶促降解是21世纪世纪的主要工业挑战之一。因此，存在发现促进多糖降解的新途径的持续动力。也许最有前途的方法涉及“纤维素酶增强因子”的应用，例如来自糖苷水解酶（CAZy）GH 61家族的那些。在这里，我们表明，GH 61酶是一个独特的铜依赖性氧化酶家族。我们证明，铜是需要GH 61的最大活性和纤维糊精和氧化纤维糊精产品的形成GH 61的增强在小分子氧化还原活性辅因子，如抗坏血酸和没食子酸的存在下。通过使用电子顺磁共振光谱和单晶X-射线衍射，GH 61的活性位点被揭示含有II型铜，并且独特地，在铜的配位球中的甲基化组氨酸，从而提供了生物无机酶催化的创新范例。
The enzymatic degradation of recalcitrant plant biomass is one of the key industrial challenges of the 21st century. Accordingly, there is a continuing drive to discover new routes to promote polysaccharide degradation. Perhaps the most promising approach involves the application of "cellulase-enhancing factors," such as those from the glycoside hydrolase (CAZy) GH61 family. Here we show that GH61 enzymes are a unique family of copper-dependent oxidases. We demonstrate that copper is needed for GH61 maximal activity and that the formation of cellodextrin and oxidized cellodextrin products by GH61 is enhanced in the presence of small molecule redox-active cofactors such as ascorbate and gallate. By using electron paramagnetic resonance spectroscopy and single-crystal X-ray diffraction, the active site of GH61 is revealed to contain a type II copper and, uniquely, a methylated histidine in the copper's coordination sphere, thus providing an innovative paradigm in bioinorganic enzymatic catalysis.