Substrate recognition by a bifunctional GH30-7 xylanase B from Talaromyces cellulolyticus.

ABSTRACT: Xylanase B, a member of subfamily 7 of the GH30 (glycoside hydrolase family 30) from Talaromyces cellulolyticus (TcXyn30B), is a bifunctional enzyme with glucuronoxylanase and xylobiohydrolase activities. In the present study, crystal structures of the native enzyme and the enzyme-product complex of TcXyn30B expressed in Pichia pastoris were determined at resolutions of 1.60 and 1.65 Å, respectively. The enzyme complexed with 2² -(4-O-methyl-α-d-glucuronyl)-xylobiose (U^4m2 X) revealed that TcXyn30B strictly recognizes both the C-6 carboxyl group and the 4-O-methyl group of the 4-O-methyl-α-d-glucuronyl side chain by the conserved residues in GH30-7 endoxylanases. The crystal structure and site-directed mutagenesis indicated that Asn-93 on the β2-α2-loop interacts with

SUBMITTER: Nakamichi Y 

PROVIDER: S-EPMC7262913 | biostudies-literature | 2020 Jun

REPOSITORIES: biostudies-literature