8chs
Human heparan sulfate N-deacetylase-N-sulfotransferase 1 in complex with calcium, 3'-phosphoadenosine-5'-phosphosulfate and nanobody nAb13 (composite map and model).
Structural highlights
FunctionNDST1_HUMAN Essential bifunctional enzyme that catalyzes both the N-deacetylation and the N-sulfation of glucosamine (GlcNAc) of the glycosaminoglycan in heparan sulfate. Modifies the GlcNAc-GlcA disaccharide repeating sugar backbone to make N-sulfated heparosan, a prerequisite substrate for later modifications in heparin biosynthesis. Plays a role in determining the extent and pattern of sulfation of heparan sulfate. Compared to other NDST enzymes, its presence is absolutely required. Participates in biosynthesis of heparan sulfate that can ultimately serve as L-selectin ligands, thereby playing a role in inflammatory response.[1] [2] Publication Abstract from PubMedHeparan sulfate (HS) polysaccharides are major constituents of the extracellular matrix, which are involved in myriad structural and signaling processes. Mature HS polysaccharides contain complex, non-templated patterns of sulfation and epimerization, which mediate interactions with diverse protein partners. Complex HS modifications form around initial clusters of glucosamine-N-sulfate (GlcNS) on nascent polysaccharide chains, but the mechanistic basis underpinning incorporation of GlcNS itself into HS remains unclear. Here, we determine cryo-electron microscopy structures of human N-deacetylase-N-sulfotransferase (NDST)1, the bifunctional enzyme primarily responsible for initial GlcNS modification of HS. Our structures reveal the architecture of both NDST1 deacetylase and sulfotransferase catalytic domains, alongside a non-catalytic N-terminal domain. The two catalytic domains of NDST1 adopt a distinct back-to-back topology that limits direct cooperativity. Binding analyses, aided by activity-modulating nanobodies, suggest that anchoring of the substrate at the sulfotransferase domain initiates the NDST1 catalytic cycle, providing a plausible mechanism for cooperativity despite spatial domain separation. Our data shed light on key determinants of NDST1 activity, and describe tools to probe NDST1 function in vitro and in vivo. Structural and mechanistic characterization of bifunctional heparan sulfate N-deacetylase-N-sulfotransferase 1.,Mycroft-West CJ, Abdelkarim S, Duyvesteyn HME, Gandhi NS, Skidmore MA, Owens RJ, Wu L Nat Commun. 2024 Feb 13;15(1):1326. doi: 10.1038/s41467-024-45419-4. PMID:38351061[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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