Download MendeleySubstrate recognition by a bifunctional GH30-7 xylanase B from Talaromyces cellulolyticus.
Nakamichi, Y., Watanabe, M., Matsushika, A., Inoue, H.(2020) FEBS Open Bio 10: 1180-1189
- PubMed: 32359208
- DOI: https://doi.org/10.1002/2211-5463.12873
- Primary Citation of Related Structures:
6KRL, 6KRN - PubMed 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 2 2 -(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 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.
Organizational Affiliation:
Research Institute for Sustainable Chemistry, National Institute of Advanced Industrial Science and Technology (AIST), Higashi-Hiroshima, Japan.
