title: NMR analysis of the binding mode of two fungal endo-β-1,4-mannanases from GH5 and GH26 families.
abstract: 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.
authors.affiliation: Department of Chemical Sciences, Università di Napoli Federico II, Complesso Universitario Monte S. Angelo, Via Cintia 4, I-80126, Naples, Italy. silipo@unina.it roberta.marchetti@unina.it.
authors.forename: Roberta
authors.initials: R
authors.lastname: Marchetti
authors.affiliation: INRA, UMR1163 BBF, 13009 Marseille, France.
authors.forename: Jean-Guy
authors.initials: JG
authors.lastname: Berrin
authors.affiliation: INRA, UMR1163 BBF, 13009 Marseille, France.
authors.forename: Marie
authors.initials: M
authors.lastname: Couturier
authors.affiliation: Department of Chemical Sciences, Università di Napoli Federico II, Complesso Universitario Monte S. Angelo, Via Cintia 4, I-80126, Naples, Italy. silipo@unina.it roberta.marchetti@unina.it and The Karachi Institute of Biotechnology and Genetic Engineering (KIBGE) University of Karachi, Karachi 75270, Pakistan.
authors.forename: Shah Ali
authors.initials: SA
authors.lastname: Ul Qader
authors.affiliation: Department of Chemical Sciences, Università di Napoli Federico II, Complesso Universitario Monte S. Angelo, Via Cintia 4, I-80126, Naples, Italy. silipo@unina.it roberta.marchetti@unina.it.
authors.forename: Antonio
authors.initials: A
authors.lastname: Molinaro
authors.affiliation: Department of Chemical Sciences, Università di Napoli Federico II, Complesso Universitario Monte S. Angelo, Via Cintia 4, I-80126, Naples, Italy. silipo@unina.it roberta.marchetti@unina.it.
authors.forename: Alba
authors.initials: A
authors.lastname: Silipo
mesh_terms: D001665:Binding Sites; D002236:Carbohydrate Conformation; D009682:Magnetic Resonance Spectroscopy; D008361:Mannosidases / Q000737:chemistry* / Q000145:classification* / Q000378:metabolism; D008958:Models, Molecular; D048468:Podospora / Q000201:enzymology
chemical_list: D008361:Mannosidases; C041867:endo-1,4-beta-D-mannanase