Abstract
Sister chromatids are held together by the multisubunit cohesin complex, which contains two SMC (Smc1 and Smc3) and two non-SMC (Scc1 and Scc3) proteins. The crystal structure of a bacterial SMC "hinge" region along with EM studies and biochemical experiments on yeast Smc1 and Smc3 proteins show that SMC protamers fold up individually into rod-shaped molecules. A 45 nm long intramolecular coiled coil separates the hinge region from the ATPase-containing "head" domain. Smc1 and Smc3 bind to each other via heterotypic interactions between their hinges to form a V-shaped heterodimer. The two heads of the V-shaped dimer are connected by different ends of the cleavable Scc1 subunit. Cohesin therefore forms a large proteinaceous loop within which sister chromatids might be entrapped after DNA replication.
Publication types
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Comparative Study
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Research Support, Non-U.S. Gov't
MeSH terms
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Adenosine Triphosphatases / chemistry
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Bacterial Proteins / chemistry
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Cell Cycle Proteins / chemistry*
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Chondroitin Sulfate Proteoglycans*
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Chromatids / metabolism
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Chromosomal Proteins, Non-Histone / chemistry*
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Cohesins
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DNA Replication
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Dimerization
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Eukaryotic Cells / metabolism
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Fungal Proteins / chemistry*
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Macromolecular Substances
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Models, Biological
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Models, Molecular
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Nuclear Proteins / chemistry*
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Phosphoproteins
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Prokaryotic Cells / metabolism
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Protein Binding
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Protein Conformation
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Protein Interaction Mapping
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Protein Structure, Tertiary
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Protein Subunits
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Recombinant Fusion Proteins / chemistry
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Saccharomyces cerevisiae Proteins / chemistry*
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Structure-Activity Relationship
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Thermotoga maritima / chemistry
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X-Ray Diffraction
Substances
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Bacterial Proteins
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Cell Cycle Proteins
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Chondroitin Sulfate Proteoglycans
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Chromosomal Proteins, Non-Histone
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Fungal Proteins
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MCD1 protein, S cerevisiae
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Macromolecular Substances
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Nuclear Proteins
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Phosphoproteins
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Protein Subunits
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Recombinant Fusion Proteins
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SMC3 protein, S cerevisiae
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Saccharomyces cerevisiae Proteins
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structural maintenance of chromosome protein 1
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Adenosine Triphosphatases