^ Niki H, Jaffé A, Imamura R, Ogura T, Hiraga S (1991)."Characterization of a prokaryotic SMC protein involved in chromosome partitioning". ^ Britton RA, Lin DC, Grossman AD (1998).elegans dosage compensation through association with the X chromosome". "DPY-27:a chromosome condensation protein homolog that regulates C. ^ Chuang PT, Albertson DG, Meyer BJ (1994)."Novel meiosis-specific isoform of mammalian SMC1". ^ Revenkova E, Eijpe M, Heyting C, Gross B, Jessberger R (2001)."A novel SMC protein complex in Schizosaccharomyces pombe contains the Rad18 DNA repair protein". "Differential contributions of condensin I and condensin II to mitotic chromosome architecture in vertebrate cells". ^ Ono T, Losada A, Hirano M, Myers MP, Neuwald AF, Hirano T (2003)."Condensins, chromosome condensation complex containing XCAP-C, XCAP-E and a Xenopus homolog of the Drosophila Barren protein". ^ Hirano T, Kobayashi R, Hirano M (1997)."Identification of Xenopus SMC protein complexes required for sister chromatid cohesion". ^ Losada A, Hirano M, Hirano T (1998)."A direct link between sister chromatid cohesion and chromosome condensation revealed through the analysis of MCD1 in S. ^ Guacci V, Koshland D, Strunnikov A (1998)."Cohesins: chromosomal proteins that prevent premature separation of sister chromatids". ^ Michaelis C, Ciosk R, Nasmyth K (1997)."Rings, bracelet or snaps: fashionable alternatives for Smc complexes". ^ Huang CE, Milutinovich M, Koshland D (2005)."The structure and function of SMC and kleisin complexes". "Dynamic molecular linkers of the genome: the first decade of SMC proteins". The following human genes encode SMC proteins: It is thought that the cycle of ATP binding and hydrolysis modulates the cycle of closing and opening of the V-shaped molecule, but the detailed mechanisms of action of SMC proteins remain to be determined. The ATP-binding domain of SMC proteins is structurally related to that of ABC transporters, a large family of transmembrane proteins that actively transport small molecules across cellular membranes. Such long "antiparallel" coiled-coils are very rare, and found only among SMC proteins (and its relatives such as Rad50). The length of the coiled-coil arms is ~50 nm long. Two protomers then dimerize through their hinge domains and assemble a V-shaped dimer. At one end of the molecule, the N-terminal and C-terminal domains together form an ATP-binding domain. To make such a unique structure, an SMC protomer is self-folded through anti-parallel coiled-coil interactions, forming a rod-shaped molecule. SMC dimers form a V-shaped molecule with two long coiled-coil arms. Walker B ATP-binding motif signature motif.They have a modular structure that is composed of the following domains: SMC proteins are 1,000-1,500 amino-acid long. Structure of SMC dimer Primary structure In a subclass of Gram-negative bacteria including Escherichia coli, a distantly related protein known as MukB plays an equivalent role. Most bacteria have a single SMC protein in individual species that forms a homodimer. SMC proteins are conserved from bacteria to humans. The nematode Caenorhabditis elegans has an SMC4-variant that has a specialized role in dosage compensation. For instance, mammals have a meiosis-specific variant of SMC1, known as SMC1β. Some organisms have variants of SMC proteins. Įach complex contains a distinct set of non-SMC regulatory subunits. A dimer composed of SMC5 and SMC6 functions as part of a yet-to-be-named complex implicated in DNA repair and checkpoint responses.Likewise, a pair of SMC2 and SMC4 acts as the core of the condensin complexes implicated in chromosome condensation.A pair of SMC1 and SMC3 constitutes the core subunits of the cohesin complexes involved in sister chromatid cohesion.Classification Eukaryotic SMCs Įukaryotes have at least six SMC proteins in individual organisms, and they form three distinct heterodimers with specialized functions:
0 kommentar(er)
