Exploring the Molecular Basis for Substrate Affinity and Structural Stability in Bacterial GH39 beta-Xylosidases

Author(s)

de Morais, Mariana Abrahao Bueno ^[1] ; Polo, Carla Cristina ^[2] ; Domingues, Mariane Noronha ^[1] ; Persinoti, Gabriela Felix ^[1] ; Pirolla, Renan Augusto Siqueira ^[1] ; de Souza, Flavio Henrique Moreira ^[1] ; Correa, Jessica Batista de Lima ^[1] ; dos Santos, Camila Ramos ^[1] ; Murakami, Mario Tyago ^[1]

Affiliation

^[1] Brazilian Ctr Res Energy & Mat, Brazilian Biorenewables Natl Lab, Campinas - Brazil

^[2] Brazilian Ctr Res Energy & Mat, Brazilian Synchrotron Light Lab, Campinas - Brazil

• Document type: Journal article
• Source: FRONTIERS IN BIOENGINEERING AND BIOTECHNOLOGY; v. 8, MAY 15 2020.
• Web of Science Citations: 0

Abstract

The glycoside hydrolase family 39 (GH39) is a functionally expanding family with limited understanding about the molecular basis for substrate specificity and extremophilicity. In this work, we demonstrate the key role of the positive-subsite region in modulating substrate affinity and how the lack of a C-terminal extension impacts on oligomerization and structural stability of some GH39 members. The crystallographic and SAXS structures of a new GH39 member from the phytopathogen Xanthomonas citri support the importance of an extended C-terminal to promote oligomerization as a molecular strategy to enhance thermal stability. Comparative structural analysis along with site-directed mutagenesis showed that two residues located at the positive-subsite region, Lys166 and Asp167, are critical to substrate affinity and catalytic performance, by inducing local changes in the active site for substrate binding. These findings expand the molecular understanding of the mechanisms involved in substrate recognition and structural stability of the GH39 family, which might be instrumental for biological insights, rational enzyme engineering and utilization in biorefineries. (AU)

• FAPESP's process: 16/19995-0 - Analysis of structural ánd functional diversity of GH43 enzymes from Xanthomonas axonopodis PV. citri: biological implications ánd potential biotechnological applications
• Grantee: Mariana Abrahão Bueno de Morais
• Support type: Scholarships in Brazil - Post-Doctorate
• FAPESP's process: 13/24622-0 - Elucidation of “The mechanistic basis of family GH62 present ín organisms specialized ín “The degradation of plant biomass
• Grantee: Flavio Henrique Moreira de Souza
• Support type: Scholarships in Brazil - Post-Doctorate
• 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 type: Research Projects - Thematic Grants