Topology and structure of an engineered human cohesin complex bound to Pds5B.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 27549742.
- Also identified by DOI 10.1038/ncomms12523 and PMC identifier 4996973.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The cohesin subunits Smc1, Smc3 and Scc1 form large tripartite rings which mediate sister chromatid cohesion and chromatin structure. These are thought to entrap DNA with the help of the associated proteins SA1/2 and Pds5A/B. Structural information is available for parts of cohesin, but analyses of entire cohesin complexes are limited by their flexibility. Here we generated a more rigid 'bonsai' cohesin by truncating the coiled coils of Smc1 and Smc3 and used single-particle electron microscopy, chemical crosslinking-mass spectrometry and in silico modelling to generate three-dimensional models of cohesin bound to Pds5B. The HEAT-repeat protein Pds5B forms a curved structure around the nucleotide-binding domains of Smc1 and Smc3 and bridges the Smc3-Scc1 and SA1-Scc1 interfaces. These results indicate that Pds5B forms an integral part of the cohesin ring by contacting all other cohesin subunits, a property that may reflect the complex role of Pds5 proteins in controlling cohesin-DNA interactions.
Medical subject headings
- Cell Cycle Proteins
- Chromosomal Proteins, Non-Histone
- DNA-Binding Proteins
- Multiprotein Complexes
- Protein Engineering
- Transcription Factors