title: Structural basis for recognition of centromere histone variant CenH3 by the chaperone Scm3.
abstract: The centromere is a unique chromosomal locus that ensures accurate segregation of chromosomes during cell division by directing the assembly of a multiprotein complex, the kinetochore. The centromere is marked by a conserved variant of conventional histone H3 termed CenH3 or CENP-A (ref. 2). A conserved motif of CenH3, the CATD, defined by loop 1 and helix 2 of the histone fold, is necessary and sufficient for specifying centromere functions of CenH3 (refs 3, 4). The structural basis of this specification is of particular interest. Yeast Scm3 and human HJURP are conserved non-histone proteins that interact physically with the (CenH3-H4)(2) heterotetramer and are required for the deposition of CenH3 at centromeres in vivo. Here we have elucidated the structural basis for recognition of budding yeast (Saccharomyces cerevisiae) CenH3 (called Cse4) by Scm3. We solved the structure of the Cse4-binding domain (CBD) of Scm3 in complex with Cse4 and H4 in a single chain model. An α-helix and an irregular loop at the conserved amino terminus and a shorter α-helix at the carboxy terminus of Scm3(CBD) wraps around the Cse4-H4 dimer. Four Cse4-specific residues in the N-terminal region of helix 2 are sufficient for specific recognition by conserved and functionally important residues in the N-terminal helix of Scm3 through formation of a hydrophobic cluster. Scm3(CBD) induces major conformational changes and sterically occludes DNA-binding sites in the structure of Cse4 and H4. These findings have implications for the assembly and architecture of the centromeric nucleosome.
authors.affiliation: Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, Bethesda, Maryland 20892, USA.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Zhou
authors.forename: Hanqiao
authors.initials: H
authors.lastname: Feng
authors.forename: Bing-Rui
authors.initials: BR
authors.lastname: Zhou
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Ghirlando
authors.forename: Kaifeng
authors.initials: K
authors.lastname: Hu
authors.forename: Adam
authors.initials: A
authors.lastname: Zwolak
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Miller Jenkins
authors.forename: Hua
authors.initials: H
authors.lastname: Xiao
authors.forename: Nico
authors.initials: N
authors.lastname: Tjandra
authors.forename: Carl
authors.initials: C
authors.lastname: Wu
authors.forename: Yawen
authors.initials: Y
authors.lastname: Bai
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001324:Autoantigens / Q000737:chemistry / Q000378:metabolism; D001665:Binding Sites; D002503:Centromere / Q000737:chemistry* / Q000378:metabolism; D000076247:Centromere Protein A; D002868:Chromosomal Proteins, Non-Histone / Q000737:chemistry* / Q000378:metabolism*; D017124:Conserved Sequence; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism*; D006657:Histones / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D008958:Models, Molecular; D018832:Molecular Chaperones / Q000737:chemistry / Q000378:metabolism; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D009707:Nucleosomes / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D001324:Autoantigens; C000619700:CENPA protein, human; C092746:CSE4 protein, S cerevisiae; D000076247:Centromere Protein A; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; C524371:HJURP protein, human; D006657:Histones; D018832:Molecular Chaperones; D009707:Nucleosomes; D029701:Saccharomyces cerevisiae Proteins; C521684:Scm3 protein, S cerevisiae; D004247:DNA