title: Crystal structure of the yeast inner kinetochore subunit Cep3p.
abstract: 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.
authors.affiliation: Jack and Eileen Connors Laboratory of Structural Biology, Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: John J
authors.initials: JJ
authors.lastname: Bellizzi
authors.forename: Peter K
authors.initials: PK
authors.lastname: Sorger
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Harrison
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002503:Centromere / Q000378:metabolism; D018360:Crystallography, X-Ray; D004271:DNA, Fungal / Q000737:chemistry / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D018386:Kinetochores / Q000737:chemistry*; D008954:Models, Biological; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000737:chemistry* / Q000378:metabolism; D011487:Protein Conformation; D021122:Protein Subunits / Q000737:chemistry / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: C092348:CEP3 protein, S cerevisiae; D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D021122:Protein Subunits; D029701:Saccharomyces cerevisiae Proteins