1qb3

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spinqualitylabelsall models 1qb3, resolution 3.Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

CRYSTAL STRUCTURE OF THE CELL CYCLE REGULATORY PROTEIN CKS1

Overview

BACKGROUND: The Saccharomyces cerevisiae protein Cks1 (cyclin-dependent, kinase subunit 1) is essential for cell-cycle progression. The biological, function of Cks1 can be modulated by a switch between two distinct, molecular assemblies: the single domain fold, which results from the, closing of a beta-hinge motif, and the intersubunit beta-strand, interchanged dimer, which arises from the opening of the beta-hinge motif., The crystal structure of a cyclin-dependent kinase (Cdk) in complex with, the human Cks homolog CksHs1 single-domain fold revealed the importance of, conserved hydrophobic residues and charged residues within the beta-hinge, motif. RESULTS: The 3.0 A resolution Cks1 structure reveals the strict, structural conservation of the Cks alpha/beta-core fold and the beta-hinge, motif. The beta hinge identified in the Cks1 structure includes a novel, pivot and exposes a cluster of conserved tyrosine residues that are, involved in Cdk binding but are sequestered in the beta-interchanged Cks, homolog suc1 dimer structure. This Cks1 structure confirms the, conservation of the Cks anion-binding site, which interacts with sidechain, residues from the C-terminal alpha helix of another subunit in the, crystal. CONCLUSIONS: The Cks1 structure exemplifies the conservation of, the beta-interchanged dimer and the anion-binding site in evolutionarily, distant yeast and human Cks homologs. Mutational analyses including in, vivo rescue of CKS1 disruption support the dual functional roles of the, beta-hinge residue Glu94, which participates in Cdk binding, and of the, anion-binding pocket that is located 22 A away and on an opposite face to, Glu94. The Cks1 structure suggests a biological role for the, beta-interchanged dimer and the anion-binding site in targeting Cdks to, specific phosphoproteins during cell-cycle progression.

About this Structure

1QB3 is a Single protein structure of sequence from Saccharomyces cerevisiae. Full crystallographic information is available from OCA.

Reference

Crystal structure and mutational analysis of the Saccharomyces cerevisiae cell cycle regulatory protein Cks1: implications for domain swapping, anion binding and protein interactions., Bourne Y, Watson MH, Arvai AS, Bernstein SL, Reed SI, Tainer JA, Structure. 2000 Aug 15;8(8):841-50. PMID:10997903

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