1h7c

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Revision as of 15:07, 12 November 2007

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spinqualitylabelsall models 1h7c, resolution 1.8Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

HUMAN TUBULIN CHAPERONE COFACTOR A

Overview

alpha and beta-Tubulin fold in a series of chaperone-assisted steps. At, least five protein cofactors are involved in the post-chaperonin tubulin, folding pathway and required to maintain the supply of tubulin; some of, them also participate in microtubule dynamics. The first tubulin chaperone, identified in the tubulin folding pathway was cofactor A (CoA). Here we, describe the three-dimensional structure of human CoA at 1.7 A resolution, determined by multiwavelength anomalous diffraction (MAD). The structure, is a monomer with a rod-like shape and consists of a three-alpha-helix, bundle, or coiled coil, with the second helix kinked by a proline break, offering a convex surface at one face of the protein. The helices are, connected by short turns, one of them, between alpha2 and alpha3, including a 3(10)-helix. Peptide mapping analysis and competition, experiments with peptides show that CoA interacts with beta-tubulin via, the three alpha-helical regions but not with the rod-end loops. The main, interaction occurs with the middle kinked alpha2 helix, at the convex face, of the rod. Strong 3D structural homology is found with the Hsp70, chaperone cofactor BAG domain, suggesting that these proteins define a, family of cofactors of simple compact architecture. Further structural, homology is found with alpha-spectrin/alpha-actinin repeats, all are rods, of identical length of ten helical turns. We propose to call these, three-helix bundles alpha ten modules.

About this Structure

1H7C is a Single protein structure of sequence from Homo sapiens with SO4 and ACY as ligands. Full crystallographic information is available from OCA.

Reference

Three-dimensional structure of human tubulin chaperone cofactor A., Guasch A, Aloria K, Perez R, Avila J, Zabala JC, Coll M, J Mol Biol. 2002 May 10;318(4):1139-49. PMID:12054808

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