6hq8 | pdb_00006hq8

Bacterial beta-1,3-oligosaccharide phosphorylase from GH149 with laminarihexaose bound at a surface site

spinqualitylabelsall models 6hq8, resolution 2.25Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6hq8 is a 2 chain structure. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: BCN, BGC, CL, EDO, SO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed Glycoside phosphorylases (GPs) with specificity for beta-(1 --> 3)-gluco-oligosaccharides are potential candidate biocatalysts for oligosaccharide synthesis. GPs with this linkage specificity are found in two families thus far-glycoside hydrolase family 94 (GH94) and the recently discovered glycoside hydrolase family 149 (GH149). Previously, we reported a crystallographic study of a GH94 laminaribiose phosphorylase with specificity for disaccharides, providing insight into the enzyme's ability to recognize its' sugar substrate/product. In contrast to GH94, characterized GH149 enzymes were shown to have more flexible chain length specificity, with preference for substrate/product with higher degree of polymerization. In order to advance understanding of the specificity of GH149 enzymes, we herein solved X-ray crystallographic structures of GH149 enzyme Pro_7066 in the absence of substrate and in complex with laminarihexaose (G6). The overall domain organization of Pro_7066 is very similar to that of GH94 family enzymes. However, two additional domains flanking its catalytic domain were found only in the GH149 enzyme. Unexpectedly, the G6 complex structure revealed an oligosaccharide surface binding site remote from the catalytic site, which, we suggest, may be associated with substrate targeting. As such, this study reports the first structure of a GH149 phosphorylase enzyme acting on beta-(1 --> 3)-gluco-oligosaccharides and identifies structural elements that may be involved in defining the specificity of the GH149 enzymes. The structure of a GH149 beta-(1 --> 3) glucan phosphorylase reveals a new surface oligosaccharide binding site and additional domains that are absent in the disaccharide-specific GH94 glucose-beta-(1 --> 3)-glucose (laminaribiose) phosphorylase.,Kuhaudomlarp S, Stevenson CEM, Lawson DM, Field RA Proteins. 2019 May 27. doi: 10.1002/prot.25745. PMID:31134667 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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