Crystal structure of the yeast inner kinetochore subunit Cep3p.
Publication Type:Journal Article
Source:Structure, Volume 15, Issue 11, p.1422-30 (2007)
Keywords:Amino Acid Sequence, Base Sequence, Centromere, Crystallography, X-Ray, DNA, Fungal, DNA-Binding Proteins, Kinetochores, Models, Biological, Models, Molecular, Molecular Sequence Data, Nuclear Proteins, Protein Conformation, Protein Subunits, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Sequence Alignment
<p>In budding yeast, the four-protein CBF3 complex (Skp1p-Ctf13p-Cep3p-Ndc10p) initiates kinetochore assembly by binding to the CDEIII locus of centromeric DNA. A Cep3p dimer recruits a Skp1p-Ctf13p heterodimer and contacts two sites on CDEIII. We report here the crystal structure, determined at 2.8 A resolution by multiple isomorphous replacement with anomalous scattering, of a truncated Cep3p (Cep3p [47-608]), comprising all but an N-terminal, Zn(2)Cys(6)-cluster, DNA-binding module. Cep3p has a well-ordered structure throughout essentially all of its polypeptide chain, unlike most yeast transcription factors, including those with Zn(2)Cys(6) clusters, such as Gal4p. This difference may reflect an underlying functional distinction: whereas any particular transcription factor must adapt to a variety of upstream activating sites, Cep3p scaffolds kinetochore assembly on centromeres uniformly configured on all 16 yeast chromosomes. We have, using the structure of Cep3p (47-608) and the known structures of Zn(2)Cys(6)-cluster domains, modeled the interaction of Cep3p with CDEIII.</p>