4W8B

Crystal structure of XEG5B, a GH5 xyloglucan-specific beta-1,4-glucanase from ruminal metagenomic library, in complex with XXLG

Summary for 4W8B

• Entry DOI: 10.2210/pdb4w8b/pdb
• Related: 4W84 4W85 4W86 4W87 4W88 4W89 4W8A
• Descriptor: Exo-xyloglucanase, alpha-D-xylopyranose-(1-6)-beta-D-glucopyranose-(1-4)-[alpha-D-xylopyranose-(1-6)]beta-D-glucopyranose-(1-4)-[beta-D-galactopyranose-(1-2)-alpha-D-xylopyranose-(1-6)]beta-D-glucopyranose-(1-4)-alpha-D-glucopyranose, alpha-D-xylopyranose-(1-6)-beta-D-glucopyranose-(1-4)-[alpha-D-xylopyranose-(1-6)]beta-D-glucopyranose-(1-4)-beta-D-glucopyranose, ... (6 entities in total)
• Functional Keywords: glycoside hydrolase, cell wall degrading enzyme, gh5 family, hydrolase
• Biological source: uncultured bacterium
• Total number of polymer chains: 1
• Total formula weight: 45147.95

Authors

Santos, C.R.,Cordeiro, R.L.,Wong, D.W.S.,Murakami, M.T. (deposition date: 2014-08-22, release date: 2015-03-11, Last modification date: 2023-12-27)

Primary citation

Dos Santos, C.R.,Cordeiro, R.L.,Wong, D.W.,Murakami, M.T.
Structural Basis for Xyloglucan Specificity and alpha-d-Xylp(1 6)-d-Glcp Recognition at the -1 Subsite within the GH5 Family.
Biochemistry, 54:1930-1942, 2015

PubMed Abstract: GH5 is one of the largest glycoside hydrolase families, comprising at least 20 distinct activities within a common structural scaffold. However, the molecular basis for the functional differentiation among GH5 members is still not fully understood, principally for xyloglucan specificity. In this work, we elucidated the crystal structures of two novel GH5 xyloglucanases (XEGs) retrieved from a rumen microflora metagenomic library, in the native state and in complex with xyloglucan-derived oligosaccharides. These results provided insights into the structural determinants that differentiate GH5 XEGs from parental cellulases and a new mode of action within the GH5 family related to structural adaptations in the -1 subsite. The oligosaccharide found in the XEG5A complex, permitted the mapping, for the first time, of the positive subsites of a GH5 XEG, revealing the importance of the pocket-like topology of the +1 subsite in conferring the ability of some GH5 enzymes to attack xyloglucan. Complementarily, the XEG5B complex covered the negative subsites, completing the subsite mapping of GH5 XEGs at high resolution. Interestingly, XEG5B is, to date, the only GH5 member able to cleave XXXG into XX and XG, and in the light of these results, we propose that a modification in the -1 subsite enables the accommodation of a xylosyl side chain at this position. The stereochemical compatibility of the -1 subsite with a xylosyl moiety was also reported for other structurally nonrelated XEGs belonging to the GH74 family, indicating it to be an essential attribute for this mode of action.

PubMed: 25714929
DOI: 10.1021/acs.biochem.5b00011

Experimental method

X-RAY DIFFRACTION (1.15 Å)