2nxq
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(New page: 200px<br /><applet load="2nxq" size="450" color="white" frame="true" align="right" spinBox="true" caption="2nxq, resolution 2.400Å" /> '''Crystal structure o...)
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Revision as of 10:51, 21 November 2007
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Crystal structure of calcium binding protein 1 from Entamoeba histolytica: a novel arrangement of EF hand motifs
Overview
Calcium plays a pivotal role in the pathogenesis of amoebiasis, a major, disease caused by Entamoeba histolytica. Several EF-hand containing, calcium-binding proteins (CaBPs) have been identified from E. histolytica., Even though these proteins have very high sequence similarity, they bind, to different target proteins in a Ca(2+) dependent manner, leading to, different functional pathways (Yadava et al., Mol Biochem Parasito, 1997;84:69-82; Chakrabarty et al., J Biol Chem 2004;279:12898-12908) The, crystal structure of the Entamoeba histolytica calcium binding protein-1, (EhCaBP1) has been determined at 2.4 A resolution. The crystals were grown, using MPD as precipitant and they belong to P6(3) space group with unit, cell parameters of a = 95.25 A, b = 95.25 A, c = 64.99 A. Only two out of, the four expected EF hand motifs could be modeled into the electron, density map and the final model refined to R factor of 25.6% and Free_R of, 28%. Unlike CaM, the first two EF hand motifs in EhCaBP1 are connected by, a long helix and form a dumbbell shaped structure. Owing to domain, swapping oligomerization three EhCaBP1 molecules interact in a head to, tail manner to form a triangular trimer. This arrangement allows the, EF-hand motif of one molecule to interact with that of an adjacent, molecule to form a two EF-hand domain similar to that seen in the, N-terminal domain of the NMR structure of CaBP1, calmodulin and troponin, C. The oligomeric state of EhCaBP1 results in reduced flexibility between, domains and may be responsible for the more limited set of targets, recognized by EhCaBP1. Proteins 2007. (c) 2007 Wiley-Liss, Inc.
About this Structure
2NXQ is a Single protein structure of sequence from Entamoeba histolytica with CA and ACT as ligands. Full crystallographic information is available from OCA.
Reference
Crystal structure of calcium binding protein-1 from Entamoeba histolytica: A novel arrangement of EF hand motifs., Kumar S, Padhan N, Alam N, Gourinath S, Proteins. 2007 Jun 6;68(4):990-998. PMID:17554780
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