Unexpected connections between type VI-B CRISPR-Cas systems, bacterial natural competence, ubiquitin signaling network and DNA modification through a distinct family of membrane proteins.

ABSTRACT: In addition to core Cas proteins, CRISPR-Cas loci often encode ancillary proteins that modulate the activity of the respective effectors in interference. Subtype VI-B1 CRISPR-Cas systems encode the Csx27 protein that down-regulates the activity of Cas13b when the type VI-B locus is expressed in Escherichia coli. We show that Csx27 belongs to an expansive family of proteins that contain four predicted transmembrane helices and are typically encoded in predicted operons with components of the bacterial natural transformation machinery, multidomain proteins that consist of components of the ubiquitin signaling system and proteins containing the ligand-binding WYL domain and a helix-turn-helix domain. The Csx27 family proteins are predicted to form membrane channels for ssDNA that might compri

SUBMITTER: Makarova KS 

PROVIDER: S-EPMC6700684 | biostudies-literature | 2019 Apr

REPOSITORIES: biostudies-literature