Mechanism of high-mannose N-glycan breakdown and metabolism by Bifidobacterium longum

Author(s):Show less -

Cordeiro, Rosa L. ; Santos, Camila R. ; Domingues, Mariane N. ; Lima, Tatiani B. ; Pirolla, Renan A. S. ; Morais, Mariana A. B. ; Colombari, Felippe M. ; Miyamoto, Renan Y. ; Persinoti, Gabriela F. ; Borges, Antonio C. ; de Farias, Marcelo A. ; Stoffel, Fabiane ; Li, Chao ; Gozzo, Fabio C. ; van Heel, Marin ; Guerin, Marcelo E. ; Sundberg, Eric J. ; Wang, Lai-Xi ; Portugal, Rodrigo V. ; Giuseppe, Priscila O. ; Murakami, Mario T.

• Document type: Journal article
• Source: Nature Chemical Biology; v. N/A, p. 27-pg., 2022-11-28.

Abstract

Bifidobacteria are early colonizers of the human gut and play central roles in human health and metabolism. To thrive in this competitive niche, these bacteria evolved the capacity to use complex carbohydrates, including mammalian N-glycans. Herein, we elucidated pivotal biochemical steps involved in high-mannose N-glycan utilization by Bifidobacterium longum. After N-glycan release by an endo-beta-N-acetylglucosaminidase, the mannosyl arms are trimmed by the cooperative action of three functionally distinct glycoside hydrolase 38 (GH38) alpha-mannosidases and a specific GH125 alpha-1,6-mannosidase. High-resolution cryo-electron microscopy structures revealed that bifidobacterial GH38 alpha-mannosidases form homotetramers, with the N-terminal jelly roll domain contributing to substrate selectivity. Additionally, an alpha-glucosidase enables the processing of monoglucosylated N-glycans. Notably, the main degradation product, mannose, is isomerized into fructose before phosphorylation, an unconventional metabolic route connecting it to the bifid shunt pathway. These findings shed light on key molecular mechanisms used by bifidobacteria to use high-mannose N-glycans, a perennial carbon and energy source in the intestinal lumen. (AU)

• FAPESP's process: 16/00740-2 - Mechanistic bases of evolutionary adaptation to temperature and specificity of glycoside hydrolases belonging to novel GH5 subfamilies
• Grantee: Rosa Lorizolla Cordeiro
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• 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: 17/15340-2 - EMU: acquisition of a transmission electron microscope for single particle cryo electron microscopy - establishing a cryo electron microscopy open facility at CNPEM
• Grantee: Rodrigo Villares Portugal
• Support Opportunities: Multi-user Equipment Program