The mechanism by which a distinguishing arabinofuranosidase can cope with internal di-substitutions in arabinoxylans

Author(s):Show less -

dos Santos, Camila Ramos ^[1] ; de Giuseppe, Priscila Oliveira ^[1] ; Moreira de Souza, Flavio Henrique ^[1] ; Zanphorlin, Leticia Maria ^[1] ; Domingues, Mariane Noronha ^[1] ; Siqueira Pirolla, Renan Augusto ^[1] ; Honorato, Rodrigo Vargas ^[2] ; Costa Tonoli, Celisa Caldana ^[2] ; Bueno de Morais, Mariana Abrahao ^[1] ; de Matos Martins, Vanesa Peixoto ^[2] ; Fonseca, Lucas Miranda ^[1] ; Buchli, Fernanda ^[1] ; Lopes de Oliveira, Paulo Sergio ^[2] ; Gozzo, Fabio Cesar ^[3] ; Murakami, Mario Tyago ^[1]

Affiliation

^[1] Brazilian Ctr Res Energy & Mat CNPEM, Brazilian Bioethanol Sci & Technol Lab CTBE, BR-13083970 Campinas, SP - Brazil

^[2] Brazilian Ctr Res Energy & Mat CNPEM, Brazilian Biosci Natl Lab LNBio, BR-13083970 Campinas, SP - Brazil

^[3] Univ Estadual Campinas, Inst Chem, Dalton Mass Spectrometry Lab, BR-13083861 Campinas, SP - Brazil

• Document type: Journal article
• Source: BIOTECHNOLOGY FOR BIOFUELS; v. 11, AUG 11 2018.
• Web of Science Citations: 2

Abstract

Background: Arabinoxylan is an abundant polysaccharide in industrially relevant biomasses such as sugarcane, corn stover and grasses. However, the arabinofuranosyl di-substitutions that decorate the xylan backbone are recalcitrant to most known arabinofuranosidases (Abfs). Results: In this work, we identified a novel GH51 Abf (XacAbf51) that forms trimers in solution and can cope efficiently with both mono- and di-substitutions at terminal or internal xylopyranosyl units of arabinoxylan. Using mass spectrometry, the kinetic parameters of the hydrolysis of 3(3)-alpha-L-arabinofuranosyl-xylotetraose and 2(3),3(3)-di-alpha-L-arabinofuranosyl-xylotetraose by XacAbf51 were determined, demonstrating the capacity of this enzyme to cleave arabinofuranosyl linkages of internal mono- and di-substituted xylopyranosyl units. Complementation studies of fungal enzyme cocktails with XacAbf51 revealed an increase of up to 20% in the release of reducing sugars from pretreated sugarcane bagasse, showing the biotechnological potential of a generalist GH51 in biomass saccharification. To elucidate the structural basis for the recognition of internal di-substitutions, the crystal structure of XacAbf51 was determined unveiling the existence of a pocket strategically arranged near to the - 1 subsite that can accommodate a second arabinofuranosyl decoration, a feature not described for any other GH51 Abf structurally characterized so far. Conclusions: In summary, this study reports the first kinetic characterization of internal di-substitution release by a GH51 Abf, provides the structural basis for this activity and reveals a promising candidate for industrial processes involving plant cell wall depolymerization. (AU)

• FAPESP's process: 13/13309-0 - Studies of the structural and functional behavior of enzymes evolutionarily specialized in the degradation of plant biomass with potential biotechnological applications
• Grantee: Mário Tyago Murakami
• Support Opportunities: Regular Research Grants
• FAPESP's process: 14/17264-3 - New frontiers in structural proteomics: characterizing protein and protein complex structures by mass spectrometry
• Grantee: Fabio Cesar Gozzo
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 15/26982-0 - Exploring novel strategies for depolymerization of plant cell-wall polysaccharides: from structure, function and rational design of glycosyl hydrolases to biological implications and potential biotechnological applications
• Grantee: Mário Tyago Murakami
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 14/07135-1 - Multi-user equipament approved in grant 2013/13309-0: Beckman Coulter capillary electrophoresis systems with LIF detection system
• Grantee: Mário Tyago Murakami
• Support Opportunities: Multi-user Equipment Program