title: Structure of Csm2 elucidates the relationship between small subunits of CRISPR-Cas effector complexes.
abstract: Type I and type III CRISPR-Cas effector complexes share similar architecture and have homologous key subunits. However, the relationship between the so-called small subunits of these complexes remains a contentious issue. Here, it is shown that the recently solved structure of Thermotoga maritima Csm2 represents a dimer with the extensive structure swapping between monomers. Unswapping the structure generates a compact globular monomer which shares similar structure and surface properties with Cmr5, the small subunit of a related Cmr complex. Detailed analysis of available structures of small subunits reveals that they all have a common fold suggesting their common origin.
authors.affiliation: Institute of Biotechnology, Vilnius University, Lithuania.
authors.forename: Česlovas
authors.initials: Č
authors.lastname: Venclovas
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism; D064130:CRISPR-Associated Proteins / Q000737:chemistry* / Q000378:metabolism*; D064113:CRISPR-Cas Systems; D008958:Models, Molecular; D055503:Protein Multimerization; D017433:Protein Structure, Secondary; D020124:Thermotoga maritima / Q000737:chemistry / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D064130:CRISPR-Associated Proteins
keywords: CRISPR-Cas; Csm2; protein fold; protein homology; small subunits; structural similarity