Structure of a CRISPR-associated protein Cas2 from Desulfovibrio vulgaris.

ABSTRACT: 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 ?????? ferredoxin fold (amino acids 1-78) to which is appended a C-terminal segment (amino acids 79-102) that includes a short 3(10)-helix and a fifth ?-strand. The ?5 strands align with the ?4 strands of the opposite protomers, resulting in two five-stranded antiparallel ?-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.

SUBMITTER: Samai P 

PROVIDER: S-EPMC2998353 | biostudies-literature | 2010 Dec

REPOSITORIES: biostudies-literature