8IDQ

Crystal structure of reducing-end xylose-releasing exoxylanase in GH30 from Talaromyces cellulolyticus with xylose

Summary for 8IDQ

• Entry DOI: 10.2210/pdb8idq/pdb
• Related: 8IDP
• Descriptor: Reducing-end xylose-releasing exoxylanase Xyn30A, beta-D-xylopyranose, CHLORIDE ION, ... (12 entities in total)
• Functional Keywords: hydrolase
• Biological source: Talaromyces pinophilus
• Total number of polymer chains: 4
• Total formula weight: 220359.58

Authors

Nakamichi, Y.,Watanabe, M.,Fujii, T.,Inoue, H.,Morita, T. (deposition date: 2023-02-14, release date: 2023-05-17, Last modification date: 2024-10-16)

Primary citation

Nakamichi, Y.,Watanabe, M.,Fujii, T.,Inoue, H.,Morita, T.
Crystal structure of reducing-end xylose-releasing exoxylanase in subfamily 7 of glycoside hydrolase family 30.
Proteins, 91:1341-1350, 2023

PubMed Abstract: TcXyn30A from Talaromyces cellulolyticus, which belongs to subfamily 7 of the glycoside hydrolase family 30 (GH30-7), releases xylose from the reducing end of xylan and xylooligosaccharides (XOSs), the so-called reducing-end xylose-releasing exoxylanase (ReX). In this study, the crystal structures of TcXyn30A with and without xylose at subsite +1 (the binding site of the xylose residue at the reducing end) were determined. This is the first report on the structure of ReX in the family GH30-7. TcXyn30A forms a dimer. The complex structure of TcXyn30A with xylose revealed that subsite +1 is located at the dimer interface. TcXyn30A recognizes xylose at subsite +1 composed of amino acid residues from each monomer and blocks substrate binding to subsite +2 by dimer formation. Thus, the dimeric conformation is responsible for ReX activity. The structural comparison between TcXyn30A and the homologous enzyme indicated that subsite -2 is composed of assembled three stacked Trp residues, Trp49, Trp333, and Trp334, allowing TcXyn30A to accommodate xylan and any branched XOSs decorated with a substitution such as α-1,2-linked 4-O-methyl-d-glucuronic acid or α-1,2- and/or -1,3-linked L-arabinofuranose. These findings provide an insight into the structural determinants for ReX activity of TcXyn30A.

PubMed: 37144255
DOI: 10.1002/prot.26505

Experimental method

X-RAY DIFFRACTION (1.7 Å)