PDBsum entry 1qb3

Cell cycle

PDB id: 1qb3

Contents

Protein chains

113 a.a. *

119 a.a. *

Waters ×24

* Residue conservation analysis

PDB id:

1qb3

Name:

Cell cycle

Title:

Crystal structure of the cell cycle regulatory protein cks1

Structure:

Cyclin-dependent kinases regulatory subunit. Chain: a, b, c. Engineered: yes

Source:

Saccharomyces cerevisiae. Baker's yeast. Organism_taxid: 4932. Expressed in: escherichia coli. Expression_system_taxid: 562.

Biol. unit:

Dimer (from PDB file)

Resolution:

3.00Å R-factor: 0.216 R-free: 0.291

Authors:

Y.Bourne,M.H.Watson,A.S.Arvai,S.L.Bernstein,S.I.Reed,J.A.Tainer

Key ref:

Y.Bourne et al. (2000). Crystal structure and mutational analysis of the Saccharomyces cerevisiae cell cycle regulatory protein Cks1: implications for domain swapping, anion binding and protein interactions. Structure, 8, 841-850. PubMed id: 10997903 DOI: 10.1016/S0969-2126(00)00175-1

Date:

30-Apr-99 Release date: 31-Aug-00

Protein chains

P20486  (CKS1_YEAST) -  Cyclin-dependent kinases regulatory subunit from Saccharomyces cerevisiae (strain ATCC 204508 / S288c)

Seq: 150 a.a.

Struc: 113 a.a.

Protein chain

P20486  (CKS1_YEAST) -  Cyclin-dependent kinases regulatory subunit from Saccharomyces cerevisiae (strain ATCC 204508 / S288c)

Seq: 150 a.a.

Struc: 119 a.a.

DOI no: 10.1016/S0969-2126(00)00175-1

Structure 8:841-850 (2000)

PubMed id: 10997903

Crystal structure and mutational analysis of the Saccharomyces cerevisiae cell cycle regulatory protein Cks1: implications for domain swapping, anion binding and protein interactions.

Y.Bourne, M.H.Watson, A.S.Arvai, S.L.Bernstein, S.I.Reed, J.A.Tainer.

ABSTRACT

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.

Selected figure(s)

Figure 4.
Figure 4. Cks1 anion-binding site and glutamine tail. (a) Glu106 and Tyr107 residues (magenta bonds and polar atoms colored spheres) within the C-terminal helix a3 (not present in other Cks structures) bind to the five invariant residues (Arg33, Arg42, Arg102, Ser82 and Trp85, orange bonds) forming the anion-binding site located at the dimer interface of two b-interchanged Cks1 dimers (yellow and blue subunits). In addition, Arg111 in helix a3 stacks against Tyr30 in b1 (green bonds in this interdimer interface). (b) Electron-density map and model for the ordered position of the glutamine tail. Stereo pair of the 3 Å resolution 2F[o]-F[c] electron-density maps, contoured at 1.2s, showing the first four glutamine residues, Gln118-Gln121, out of the 16 present in the Cks1 glutamine tail.

The above figure is reprinted by permission from Cell Press: Structure (2000, 8, 841-850) copyright 2000.

Figure was selected by an automated process.