8DO6

The structure of S. epidermidis Cas10-Csm bound to target RNA

Summary for 8DO6

• Entry DOI: 10.2210/pdb8do6/pdb
• EMDB information: 27593
• Descriptor: CRISPR system Cms endoribonuclease Csm3, crRNA, Target RNA, ... (6 entities in total)
• Functional Keywords: crispr, cas10, type iii, csm, rna binding protein, rna binding protein-rna complex, rna binding protein/rna
• Biological source: Staphylococcus epidermidis RP62A; More
• Total number of polymer chains: 9
• Total formula weight: 205217.08

Authors

Paraan, M.,Stagg, S.M.,Dunkle, J.A. (deposition date: 2022-07-12, release date: 2023-06-21, Last modification date: 2024-06-12)

Primary citation

Paraan, M.,Nasef, M.,Chou-Zheng, L.,Khweis, S.A.,Schoeffler, A.J.,Hatoum-Aslan, A.,Stagg, S.M.,Dunkle, J.A.
The structure of a Type III-A CRISPR-Cas effector complex reveals conserved and idiosyncratic contacts to target RNA and crRNA among Type III-A systems.
Plos One, 18:e0287461-e0287461, 2023

PubMed Abstract: Type III CRISPR-Cas systems employ multiprotein effector complexes bound to small CRISPR RNAs (crRNAs) to detect foreign RNA transcripts and elicit a complex immune response that leads to the destruction of invading RNA and DNA. Type III systems are among the most widespread in nature, and emerging interest in harnessing these systems for biotechnology applications highlights the need for detailed structural analyses of representatives from diverse organisms. We performed cryo-EM reconstructions of the Type III-A Cas10-Csm effector complex from S. epidermidis bound to an intact, cognate target RNA and identified two oligomeric states, a 276 kDa complex and a 318 kDa complex. 3.1 Å density for the well-ordered 276 kDa complex allowed construction of atomic models for the Csm2, Csm3, Csm4 and Csm5 subunits within the complex along with the crRNA and target RNA. We also collected small-angle X-ray scattering data which was consistent with the 276 kDa Cas10-Csm architecture we identified. Detailed comparisons between the S. epidermidis Cas10-Csm structure and the well-resolved bacterial (S. thermophilus) and archaeal (T. onnurineus) Cas10-Csm structures reveal differences in how the complexes interact with target RNA and crRNA which are likely to have functional ramifications. These structural comparisons shed light on the unique features of Type III-A systems from diverse organisms and will assist in improving biotechnologies derived from Type III-A effector complexes.

PubMed: 37352230
DOI: 10.1371/journal.pone.0287461

Experimental method

ELECTRON MICROSCOPY (3.1 Å)