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Publication Abstract from PubMed

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 A, respectively. The enzyme complexed with 2(2) -(4-O-methyl-alpha-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-alpha-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 beta2-alpha2-loop interacts with the non-reducing end of the xylose residue at subsite-2 and is likely to be involved in xylobiohydrolase activity. These findings provide structural insight into the mechanisms of substrate recognition of GH30-7 glucuronoxylanase and xylobiohydrolase.

Substrate recognition by a bifunctional GH30-7 xylanase B from Talaromyces cellulolyticus.,Nakamichi Y, Watanabe M, Matsushika A, Inoue H FEBS Open Bio. 2020 Jun;10(6):1180-1189. doi: 10.1002/2211-5463.12873. Epub 2020 , May 22. PMID:32359208^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.