The replication initiator of the cholera pathogen's second chromosome shows structural similarity to plasmid initiators.

ABSTRACT: The conserved DnaA-oriC system is used to initiate replication of primary chromosomes throughout the bacterial kingdom; however, bacteria with multipartite genomes evolved distinct systems to initiate replication of secondary chromosomes. In the cholera pathogen, Vibrio cholerae, and in related species, secondary chromosome replication requires the RctB initiator protein. Here, we show that RctB consists of four domains. The structure of its central two domains resembles that of several plasmid replication initiators. RctB contains at least three DNA binding winged-helix-turn-helix motifs, and mutations within any of these severely compromise biological activity. In the structure, RctB adopts a head-to-head dimeric configuration that likely reflects the arrangement in solution. Therefore,

SUBMITTER: Orlova N 

PROVIDER: S-EPMC5397143 | biostudies-literature | 2017 Apr

REPOSITORIES: biostudies-literature