Is the function of the cdc2 kinase subunit proteins tuned by their propensities to oligomerize? Conformational states in solution of the cdc2 kinase partners p13suc1 and p9cksphy.
The cdc2 kinase subunit (cks) proteins play an essential function in the control of mitosis through their molecular complexes with the cdc2 kinase. In this work, we characterize the conformational state(s) in solution of the cks proteins p13suc1 from Schizosaccharomyces pombe and p9cksphy from Physarum polycephalum. Monomers of p13suc1 and p9cksphy were found to be markedly nonglobular, presumably with a long, nonfolded C-terminal moiety. This was in contrast to the previously published structure of p13suc1, derived from crystallographic studies on a zinc-promoted p13suc1 dimer, in which the individual p13suc1 subunits had a globular conformation. This disparity was resolved when we found that the globular p13suc1 fold undergoes a conformational transition into nonglobular monomers upon dissociation of the dimers following chelation of the zinc ions by ethylenediaminetetraacetic acid (EDTA). We also found that p13suc1, but not p9cksphy, forms stable dimers in the absence of metal ions. The topology of these EDTA-insensitive dimers likely resembles that of the human p9ckshs2 protein, characterized by beta 4 strand exchange from each nonglobular monomer.
Birck
C
C
Groupe de Cristallographie Biologique du Laboratoire de Pharmacologie et de Toxicologie Fondamentales du CNRS, Toulouse, France.
Vachette
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P
Welch
M
M
Swarén
P
P
Samama
J P
JP
D000595:Amino Acid Sequence; D000818:Animals; D016203:CDC2 Protein Kinase / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000378:metabolism*; D005656:Fungal Proteins / Q000378:metabolism*; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D008970:Molecular Weight; D016839:Physarum polycephalum; D011485:Protein Binding; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D015800:Protozoan Proteins; D011994:Recombinant Proteins; D012542:Scattering, Radiation; D012568:Schizosaccharomyces; D029702:Schizosaccharomyces pombe Proteins; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014965:X-Rays
D018797:Cell Cycle Proteins; D005656:Fungal Proteins; D046911:Macromolecular Substances; D015800:Protozoan Proteins; D011994:Recombinant Proteins; D029702:Schizosaccharomyces pombe Proteins; C051655:Suc1 protein, S pombe; C093296:cksphy protein, Physarum polycephalum; D016203:CDC2 Protein Kinase