title: ScII: an abundant chromosome scaffold protein is a member of a family of putative ATPases with an unusual predicted tertiary structure.
abstract: Here, we describe the cloning and characterization of ScII, the second most abundant protein after topoisomerase II, of the chromosome scaffold fraction to be identified. ScII is structurally related to a protein, Smc1p, previously found to be required for accurate chromosome segregation in Saccharomyces cerevisiae. ScII and the other members of the emerging family of SMC1-like proteins are likely to be novel ATPases, with NTP-binding A and B sites separated by two lengthy regions predicted to form an alpha-helical coiled-coil. Analysis of the ScII B site predicted that ScII might use ATP by a mechanism similar to the bacterial recN DNA repair and recombination enzyme. ScII is a mitosis-specific scaffold protein that colocalizes with topoisomerase II in mitotic chromosomes. However, ScII appears not to be associated with the interphase nuclear matrix. ScII might thus play a role in mitotic processes such as chromosome condensation or sister chromatid disjunction, both of which have been previously shown to involve topoisomerase II.
authors.affiliation: Department of Cell Biology and Anatomy, Johns Hopkins School of Medicine, Baltimore, Maryland 21205.
authors.forename: N
authors.initials: N
authors.lastname: Saitoh
authors.forename: I G
authors.initials: IG
authors.lastname: Goldberg
authors.forename: E R
authors.initials: ER
authors.lastname: Wood
authors.forename: W C
authors.initials: WC
authors.lastname: Earnshaw
mesh_terms: D000251:Adenosine Triphosphatases / Q000032:analysis / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D030161:Avian Proteins; D001483:Base Sequence; D001665:Binding Sites; D018797:Cell Cycle Proteins; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D002642:Chick Embryo; D002645:Chickens; D002842:Chromatids / Q000737:chemistry; D002868:Chromosomal Proteins, Non-Histone; D002875:Chromosomes / Q000737:chemistry*; D003001:Cloning, Molecular; D004250:DNA Topoisomerases, Type II / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000032:analysis / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D005656:Fungal Proteins / Q000737:chemistry; D007399:Interphase; D008938:Mitosis; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015530:Nuclear Matrix / Q000737:chemistry; D009687:Nuclear Proteins / Q000032:analysis / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D009711:Nucleotides / Q000378:metabolism; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D012441:Saccharomyces cerevisiae / Q000737:chemistry; D000098550:Structural Maintenance of Chromosome Protein 1
chemical_list: D030161:Avian Proteins; D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D009687:Nuclear Proteins; D009711:Nucleotides; C089784:ScII protein, Gallus gallus; D000098550:Structural Maintenance of Chromosome Protein 1; D000251:Adenosine Triphosphatases; D004250:DNA Topoisomerases, Type II