Marchetti Roberta, Berrin Jean-Guy, Couturier Marie, Ul Qader Shah Ali, Molinaro Antonio, Silipo Alba
Department of Chemical Sciences, Università di Napoli Federico II, Complesso Universitario Monte S. Angelo, Via Cintia 4, I-80126, Naples, Italy.
INRA, UMR1163 BBF, 13009 Marseille, France.
Org Biomol Chem. 2016 Jan 7;14(1):314-22. doi: 10.1039/c5ob01851j.
The enzymatic digestion of the main components of lignocellulosic biomass, including plant cell wall mannans, constitutes a fundamental step in the renewable biofuel production, with great potential benefit in the industrial field. Despite several reports of X-ray structures of glycoside hydrolases, how polysaccharides are specifically recognized and accommodated in the enzymes binding site still remains a pivotal matter of research. Within this frame, NMR spectroscopic techniques provide key binding information, complementing and/or enhancing the structural view by X-ray crystallography. Here we provide deep insights into the binding mode of two endo-β-1,4 mannanases from the coprophilous ascomycete Podospora anserina, PaMan26A and PaMan5A, involved in the hydrolysis of plant cell wall mannans and heteromannans. The investigation at a molecular level of the interaction between the wild-type enzymes and inactive mutants with manno-oligosaccharides, revealed a different mode of action among the two glycoside hydrolases most likely due to the presence of the additional and peculiar -4 subsite in the PaMan26A binding pocket.
木质纤维素生物质主要成分（包括植物细胞壁甘露聚糖）的酶促消化是可再生生物燃料生产的一个基本步骤，在工业领域具有巨大的潜在益处。尽管已有多篇关于糖苷水解酶X射线结构的报道，但多糖如何在酶的结合位点被特异性识别和容纳仍是一个关键的研究问题。在此框架内，核磁共振光谱技术提供了关键的结合信息，补充和/或增强了X射线晶体学的结构观点。在这里，我们深入了解了来自粪生子囊菌Podospora anserina的两种内切-β-1,4甘露聚糖酶PaMan26A和PaMan5A的结合模式，它们参与植物细胞壁甘露聚糖和杂甘露聚糖的水解。对野生型酶与甘露寡糖的无活性突变体之间相互作用的分子水平研究表明，这两种糖苷水解酶的作用模式不同，这很可能是由于PaMan26A结合口袋中存在额外且特殊的-4亚位点。
