A novel relaxase homologue is involved in chromosomal DNA processing for type IV secretion in Neisseria gonorrhoeae.

ABSTRACT: The Neisseria gonorrhoeae type IV secretion system secretes chromosomal DNA that acts in natural transformation. To examine the mechanism of DNA processing for secretion, we made mutations in the putative relaxase gene traI and used nucleases to characterize the secreted DNA. The nuclease experiments demonstrated that the secreted DNA is single-stranded and blocked at the 5' end. Mutation of traI identified Tyr93 as required for DNA secretion, while substitution of Tyr201 resulted in intermediate levels of DNA secretion. TraI exhibits features of relaxases, but also has features that are absent in previously characterized relaxases, including an HD phosphohydrolase domain and an N-terminal hydrophobic region. The HD domain residue Asp120 was required for wild-type levels of DNA secretion.

SUBMITTER: Salgado-Pabon W 

PROVIDER: S-EPMC2586181 | biostudies-literature | 2007 Nov

REPOSITORIES: biostudies-literature