2wce
calcium-free (apo) S100A12calcium-free (apo) S100A12
Structural highlights
FunctionS10AC_HUMAN S100A12 is a calcium-, zinc- and copper-binding protein which plays a prominent role in the regulation of inflammatory processes and immune response. Its proinflammatory activity involves recruitment of leukocytes, promotion of cytokine and chemokine production, and regulation of leukocyte adhesion and migration. Acts as an alarmin or a danger associated molecular pattern (DAMP) molecule and stimulates innate immune cells via binding to receptor for advanced glycation endproducts (AGER). Binding to AGER activates the MAP-kinase and NF-kappa-B signaling pathways leading to production of proinflammatory cytokines and up-regulation of cell adhesion molecules ICAM1 and VCAM1. Acts as a monocyte and mast cell chemoattractant. Can stimulate mast cell degranulation and activation which generates chemokines, histamine and cytokines inducing further leukocyte recruitment to the sites of inflammation. Can inhibit the activity of matrix metalloproteinases; MMP2, MMP3 and MMP9 by chelating Zn(2+) from their active sites. Possesses filariacidal and filariastatic activity. Calcitermin possesses antifungal activity against C.albicans and is also active against E.coli and P.aeruginosa but not L.monocytogenes and S.aureus.[1] [2] [3] [4] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe functions of the members of the S100 family of EF-hand proteins are modulated by calcium and, in a number of cases, by zinc or copper. One such protein is S100A12, which is implicated in inflammation and host-parasite responses. Previously, we reported the structures of human S100A12 in both low (dimeric) and high (hexameric) calcium forms and, in addition, that of a complex with copper and calcium. Here we report the crystal structures of the metal-free apo form of human S100A12 at 1.77 A resolution and of the zinc complex in two crystal forms (P2(1)2(1)2(1) and F222) to 1.88 A and 1.73 A resolution, respectively. These are the first structures of a zinc-only complex of an S100 protein to be determined. The zinc complex structure shows significant differences from those of both calcium-loaded and apo-S100A12 structures, and comparisons suggest an explanation for the zinc-induced 1500-fold increase in calcium affinity. In addition, the new structures provide insight into the role of zinc-calcium interplay in the transition of S100A12 from a dimer through a tetramer to a hexamer. The role of both zinc and calcium in target binding by S100A12 during host-parasite responses is confirmed by experiments with paramyosin from the tropical parasites Onchocerca volvulus and Brugia malayi. The crystal structures of human S100A12 in apo form and in complex with zinc: new insights into S100A12 oligomerisation.,Moroz OV, Blagova EV, Wilkinson AJ, Wilson KS, Bronstein IB J Mol Biol. 2009 Aug 21;391(3):536-51. Epub 2009 Jun 6. PMID:19501594[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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