Endo-fucoidan hydrolases from glycoside hydrolase family 107 (GH107) display structural and mechanistic similarities to α-l-fucosidases from GH29.

Autor:	Vickers C; From the Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia 8W 3P6, Canada., Liu F; the Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada, and., Abe K; From the Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia 8W 3P6, Canada., Salama-Alber O; From the Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia 8W 3P6, Canada., Jenkins M; From the Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia 8W 3P6, Canada., Springate CMK; ARC Medical Devices Inc., Richmond, British Columbia V6X 2T4, Canada., Burke JE; From the Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia 8W 3P6, Canada., Withers SG; the Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada, and., Boraston AB; From the Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia 8W 3P6, Canada,. Electronic address: boraston@uvic.ca.
Jazyk:	angličtina
Zdroj:	The Journal of biological chemistry [J Biol Chem] 2018 Nov 23; Vol. 293 (47), pp. 18296-18308. Date of Electronic Publication: 2018 Oct 03.
DOI:	10.1074/jbc.RA118.005134
Abstrakt:	Fucoidans are chemically complex and highly heterogeneous sulfated marine fucans from brown macro algae. Possessing a variety of physicochemical and biological activities, fucoidans are used as gelling and thickening agents in the food industry and have anticoagulant, antiviral, antitumor, antibacterial, and immune activities. Although fucoidan-depolymerizing enzymes have been identified, the molecular basis of their activity on these chemically complex polysaccharides remains largely uninvestigated. In this study, we focused on three glycoside hydrolase family 107 (GH107) enzymes: MfFcnA and two newly identified members, P5AFcnA and P19DFcnA, from a bacterial species of the genus Psychromonas Using carbohydrate-PAGE, we show that P5AFcnA and P19DFcnA are active on fucoidans that differ from those depolymerized by MfFcnA, revealing differential substrate specificity within the GH107 family. Using a combination of X-ray crystallography and NMR analyses, we further show that GH107 family enzymes share features of their structures and catalytic mechanisms with GH29 α-l-fucosidases. However, we found that GH107 enzymes have the distinction of utilizing a histidine side chain as the proposed acid/base catalyst in its retaining mechanism. Further interpretation of the structural data indicated that the active-site architectures within this family are highly variable, likely reflecting the specificity of GH107 enzymes for different fucoidan substructures. Together, these findings begin to illuminate the molecular details underpinning the biological processing of fucoidans. (© 2018 Vickers et al.)
Databáze:	MEDLINE
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