3cs1 | pdb_00003cs1

Flagellar Calcium-binding Protein (FCaBP) from T. cruzi

spinqualitylabelsall models 3cs1, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3cs1 is a 1 chain structure with sequence from Trypanosoma cruzi. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. NonStd Res: CSX Gene: FCABP (Trypanosoma cruzi) Resources: FirstGlance, OCA, RCSB, PDBsum 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 PubMed The flagellar calcium-binding protein (FCaBP) of the protozoan Trypanosoma cruzi is targeted to the flagellar membrane where it regulates flagellar function and assembly. As a first step toward understanding the Ca(2+)-induced conformational changes important for membrane-targeting, we report here the x-ray crystal structure of FCaBP in the Ca(2+)-free state determined at 2.2A resolution. The first 17 residues from the N terminus appear unstructured and solvent-exposed. Residues implicated in membrane targeting (Lys-19, Lys-22, and Lys-25) are flanked by an exposed N-terminal helix (residues 26-37), forming a patch of positive charge on the protein surface that may interact electrostatically with flagellar membrane targets. The four EF-hands in FCaBP each adopt a "closed conformation" similar to that seen in Ca(2+)-free calmodulin. The overall fold of FCaBP is closest to that of grancalcin and other members of the penta EF-hand superfamily. Unlike the dimeric penta EF-hand proteins, FCaBP lacks a fifth EF-hand and is monomeric. The unstructured N-terminal region of FCaBP suggests that its covalently attached myristoyl group at the N terminus may be solvent-exposed, in contrast to the highly sequestered myristoyl group seen in recoverin and GCAP1. NMR analysis demonstrates that the myristoyl group attached to FCaBP is indeed solvent-exposed in both the Ca(2+)-free and Ca(2+)-bound states, and myristoylation has no effect on protein structure and folding stability. We propose that exposed acyl groups at the N terminus may anchor FCaBP to the flagellar membrane and that Ca(2+)-induced conformational changes may control its binding to membrane-bound protein targets. Structural insights into membrane targeting by the flagellar calcium-binding protein (FCaBP), a myristoylated and palmitoylated calcium sensor in Trypanosoma cruzi.,Wingard JN, Ladner J, Vanarotti M, Fisher AJ, Robinson H, Buchanan KT, Engman DM, Ames JB J Biol Chem. 2008 Aug 22;283(34):23388-96. Epub 2008 Jun 17. PMID:18559337 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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