Structure of a CRISPR-associated protein Cas2 from Desulfovibrio vulgaris

• Published in: Acta crystallographica. Section F, Structural biology and crystallization communications Vol. 66; no. 12; pp. 1552 - 1556
• Main Authors: Samai, Poulami, Smith, Paul, Shuman, Stewart
• Format: Journal Article
• Language: English
• Published: 5 Abbey Square, Chester, Cheshire CH1 2HU, England International Union of Crystallography 01.12.2010
• Subjects: Amino Acid Sequence; Bacterial Proteins - chemistry; Cas2; Catalytic Domain; CRISPR-associated proteins; Crystallography, X-Ray; Desulfovibrio vulgaris; Desulfovibrio vulgaris - chemistry; Molecular Sequence Data; Phosphoric Diester Hydrolases - metabolism; Protein Multimerization; Protein Structure, Secondary; Repetitive Sequences, Amino Acid; Sequence Homology, Amino Acid; Structural Communications
• ISSN: 1744-3091; 1744-3091
• DOI: 10.1107/S1744309110039801

CRISPRs (clustered regularly interspaced short palindromic repeats) provide bacteria and archaea with RNA‐guided acquired immunity to invasive DNAs. CRISPR‐associated (Cas) proteins carry out the immune effector functions. Cas2 is a universal component of the CRISPR system. Here, a 1.35 Å resolution crystal structure of Cas2 from the bacterium Desulfovibrio vulgaris (DvuCas2) is reported. DvuCas2 is a homodimer, with each protomer consisting of an N‐terminal βαββαβ ferredoxin fold (amino acids 1–78) to which is appended a C‐terminal segment (amino acids 79–102) that includes a short 310‐helix and a fifth β‐strand. The β5 strands align with the β4 strands of the opposite protomers, resulting in two five‐stranded antiparallel β‐sheets that form a sandwich at the dimer interface. The DvuCas2 dimer is stabilized by a distinctive network of hydrophilic cross‐protomer side‐chain interactions.