Middle HEAT-repeat binding domain found in Saccharomyces cerevisiae sister chromatid cohesion protein 1 (ScScc1p) and similar proteins
ScScc1p, also called Mcd1, or Rhc21, or Pds3, is a cleavable component of the cohesin complex involved in chromosome cohesion during the cell cycle. The cohesin complex is required for the cohesion of sister chromatids after DNA replication. The cohesin complex apparently forms a large proteinaceous ring within which sister chromatids can be trapped. At the metaphase-anaphase transition, ScScc1p is cleaved by ESP1 and dissociates from chromatin, allowing sister chromatids to segregate. This model corresponds to HEAT-repeat binding domain of ScScc1p in the middle region, which consists of short helices and two long extended segments. It is responsible for the binding of the budding yeast cohesin HEAT-repeat subunit Scc3. The Scc3-Scc1 subcomplex engages double-stranded DNA through a conserved, positively charged surface, and plays a central role in the recruitment of cohesin complexes to chromosomes and therefore for cohesin to faithfully execute its functions during cell division.
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