2hyu
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Human Annexin A2 with heparin tetrasaccharide bound
OverviewOverview
Annexin A2 and heparin bind to one another with high affinity and in a, calcium-dependent manner, an interaction that may play a role in mediating, fibrinolysis. In this study, three heparin-derived oligosaccharides of, different lengths were co-crystallized with annexin A2 to elucidate the, structural basis of the interaction. Crystal structures were obtained at, high resolution for uncomplexed annexin A2 and three complexes of heparin, oligosaccharides bound to annexin A2. The common heparin-binding site is, situated at the convex face of domain IV of annexin A2. At this site, annexin A2 binds up to five sugar residues from the nonreducing end of the, oligosaccharide. Unlike most heparin-binding consensus patterns, heparin, binding at this site does not rely on arrays of basic residues; instead, main-chain and side-chain nitrogen atoms and two calcium ions play, important roles in the binding. Especially significant is a novel, calcium-binding site that forms upon heparin binding. Two sugar residues, of the heparin derivatives provide oxygen ligands for this calcium ion., Comparison of all four structures shows that heparin binding does not, elicit a significant conformational change in annexin A2. Finally, surface, plasmon resonance measurements were made for binding interactions between, annexin A2 and heparin polysaccharide in solution at pH 7.4 or 5.0. The, combined data provide a clear basis for the calcium dependence of heparin, binding to annexin A2.
About this StructureAbout this Structure
2HYU is a Single protein structure of sequence from Homo sapiens with as ligand. Full crystallographic information is available from OCA.
ReferenceReference
Crystallographic analysis of calcium-dependent heparin binding to annexin A2., Shao C, Zhang F, Kemp MM, Linhardt RJ, Waisman DM, Head JF, Seaton BA, J Biol Chem. 2006 Oct 20;281(42):31689-95. Epub 2006 Aug 1. PMID:16882661
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