7XZ3

Crystal structure of the Type I-B CRISPR-associated protein, Csh2 from Thermobaculum terrenum

Summary for 7XZ3

• Entry DOI: 10.2210/pdb7xz3/pdb
• Descriptor: CRISPR-associated protein, Csh2 family (2 entities in total)
• Functional Keywords: rna binding protein, transferase
• Biological source: Thermobaculum terrenum
• Total number of polymer chains: 2
• Total formula weight: 73380.11

Authors

Seo, P.W.,Gu, D.H.,Park, S.Y.,Kim, J.S. (deposition date: 2022-06-02, release date: 2023-05-31, Last modification date: 2023-11-29)

Primary citation

Seo, P.W.,Gu, D.H.,Kim, J.W.,Kim, J.H.,Park, S.Y.,Kim, J.S.
Structural characterization of the type I-B CRISPR Cas7 from Thermobaculum terrenum.
Biochim Biophys Acta Proteins Proteom, 1871:140900-140900, 2023

PubMed Abstract: Clustered regularly interspaced short palindromic repeats (CRISPR) in many prokaryotes functions as an adaptive immune system against mobile genetic elements. A heterologous ribonucleoprotein silencing complex composed of CRISPR-associated (Cas) proteins and a CRISPR RNA (crRNA) neutralizes the incoming mobile genetic elements. The type I and III silencing complexes commonly include a protein-helical backbone of several copies of identical subunits, for example, Cas7 in the type I silencing complex. In this study, we structurally characterized type I-B Cas7 (Csh2 from Thermobaculum terrenum; TterCsh2). The revealed crystal structure of TterCsh2 shows a typical glove-like architecture of Cas7, which consists of a palm, a thumb, and a finger domain. Csh2 proteins have 5 conserved sequence motifs that are arranged to form a presumable crRNA-binding site in the TterCsh2 structure. This crRNA binding site of TterCsh2 is structurally and potentially comparable to those observed in helix-forming Cas7 structures in other sub-types. Analysis of the reported Cas7 structures and their sequences suggests that Cas7s can be divided into at least two sub-classes. These data will broaden our understanding on the Cascade complex of CRISPR/Cas systems.

PubMed: 36682394
DOI: 10.1016/j.bbapap.2023.140900

Experimental method

X-RAY DIFFRACTION (1.889 Å)