title: Domain structure of separase and its binding to securin as determined by EM.
abstract: After the degradation of its inhibitor securin, separase initiates chromosome segregation during the metaphase-to-anaphase transition by cleaving cohesin. Here we present a density map at a resolution of 25 A of negatively stained separase-securin complex. Based on labeling data and sequence analysis, we propose a model for the structure of separase, consisting of 26 ARM repeats, an unstructured region of 280 residues and two caspase-like domains, with securin binding to the ARM repeats.
authors.affiliation: Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, Massachusetts 02115, USA.
authors.forename: Hector
authors.initials: H
authors.lastname: Viadiu
authors.forename: Olaf
authors.initials: O
authors.lastname: Stemmann
authors.forename: Marc W
authors.initials: MW
authors.lastname: Kirschner
authors.forename: Thomas
authors.initials: T
authors.lastname: Walz
mesh_terms: D018797:Cell Cycle Proteins / Q000737:chemistry* / Q000378:metabolism* / Q000648:ultrastructure; D010450:Endopeptidases / Q000737:chemistry* / Q000378:metabolism* / Q000648:ultrastructure; D006801:Humans; D008854:Microscopy, Electron; D008958:Models, Molecular; D009363:Neoplasm Proteins / Q000737:chemistry* / Q000378:metabolism* / Q000648:ultrastructure; D011487:Protein Conformation; D017510:Protein Folding; D064249:Securin; D064247:Separase
chemical_list: D018797:Cell Cycle Proteins; D009363:Neoplasm Proteins; D064249:Securin; C578002:pituitary tumor-transforming protein 1, human; D010450:Endopeptidases; C577987:ESPL1 protein, human; D064247:Separase