Biology; Chemistry and chemical biology; Chemical and biological engineering; Biomedical engineering
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Conformational Flexibility of Heparinases from PL12 family: Crystal Structure and Substrate Specificity of Heparinase III from Bacteroides thetaiotaomicron, T. S. Ulaganathan, R. Shi, D. Yao, Y. Li, M.-L. Garron, M. Cherney, R.-X. Gu, D. P. Tieleman, E. Sterner, G. Li, L. Li, R. J. Linhardt, M. Cygler, Glycobiology, 27, 176–187, 2017.
Glycosaminoglycans (GAGs) are linear polysaccharides comprised of disaccharide repeat units, a hexuronic acid, glucuronic acid or iduronic acid, linked to a hexosamine, N-acetylglucosamine (GlcNAc) or N-acetylgalactosamine. GAGs undergo further modification such as epimerization and sulfation. These polysaccharides are abundant in the extracellular matrix and connective tissues. GAGs function in stabilization of the fibrillar extracellular matrix, control of hydration, regulation of tissue, organism development by controlling cell cycle, cell behavior and differentiation. Niche adapted bacteria express enzymes called polysaccharide lyases (PL), which degrade GAGs for their nutrient content. PL have been classified into 24 sequence-related families. Comparison of 3D structures of the prototypic members of these families allowed identification of distant evolutionary relationships between lyases that were unrecognized at the sequence level, and identified occurrences of convergent evolution. We have characterized structurally and enzymatically heparinase III from Bacteroides thetaiotaomicron (BtHepIII; gene BT4657), which is classified within the PL12 family. BtHepIII is a 72.5 kDa protein. We present the X-ray structures of two crystal forms of BtHepIII at resolution 1.8 and 2.4 Å. BtHepIII contains two domains, the N-terminal α-helical domain forming a toroid and the C-terminal β-sheet domain. Comparison with recently determined structures of two other heparinases from the same PL12 family allowed us to identify structural flexibility in the arrangement of the domains indicating open–close movement. Based on comparison with other GAG lyases, we identified Tyr301 as the main catalytic residue and confirmed this by site-directed mutagenesis. We have characterized substrate preference of BtHepIII toward sulfate-poor heparan sulfate substrate.;
Glycobiology, 27, 176–187; Note : if this item contains full text it may be a preprint, author manuscript, or a Gold OA copy that permits redistribution with a license such as CC BY. The final version is available through the publisher’s platform.
The Linhardt Research Labs.; The Shirley Ann Jackson, Ph.D. Center for Biotechnology and Interdisciplinary Studies (CBIS);
The Linhardt Research Labs Online Collection; Rensselaer Polytechnic Institute, Troy, NY; https://harc.rpi.edu/;