title: Differential arrangements of conserved building blocks among homologs of the Rad50/Mre11 DNA repair protein complex.
abstract: Structural maintenance of chromosomes (SMC) proteins have diverse cellular functions including chromosome segregation, condensation and DNA repair. They are grouped based on a conserved set of distinct structural motifs. All SMC proteins are predicted to have a bipartite ATPase domain that is separated by a long region predicted to form a coiled coil. Recent structural data on a variety of SMC proteins shows them to be arranged as long intramolecular coiled coils with a globular ATPase at one end. SMC proteins function in pairs as heterodimers or as homodimers often in complexes with other proteins. We expect the arrangement of the SMC protein domains in complex assemblies to have important implications for their diverse functions. We used scanning force microscopy imaging to determine the architecture of human, Saccharomyces cerevisiae, and Pyrococcus furiosus Rad50/Mre11, Escherichia coli SbcCD, and S.cerevisiae SMC1/SMC3 cohesin SMC complexes. Two distinct architectural arrangements are described, based on the way their components were connected. The eukaryotic complexes were similar to each other and differed from their prokaryotic and archaeal homologs. These similarities and differences are discussed with respect to their diverse mechanistic roles in chromosome metabolism.
authors.affiliation: Department of Cell Biology and Genetics, Erasmus MC, P.O. Box 1738, 3000 DR Rotterdam, The Netherlands.
authors.forename: Martijn
authors.initials: M
authors.lastname: de Jager
authors.forename: Kelly M
authors.initials: KM
authors.lastname: Trujillo
authors.forename: Patrick
authors.initials: P
authors.lastname: Sung
authors.forename: Karl-Peter
authors.initials: KP
authors.lastname: Hopfner
authors.forename: James P
authors.initials: JP
authors.lastname: Carney
authors.forename: John A
authors.initials: JA
authors.lastname: Tainer
authors.forename: John C
authors.initials: JC
authors.lastname: Connelly
authors.forename: David R F
authors.initials: DR
authors.lastname: Leach
authors.forename: Roland
authors.initials: R
authors.lastname: Kanaar
authors.forename: Claire
authors.initials: C
authors.lastname: Wyman
mesh_terms: D000595:Amino Acid Sequence; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity
chemical_list: D004268:DNA-Binding Proteins; C086930:RAD50 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins