Protein and DNA effectors control the TraI conjugative helicase of plasmid R1.

ABSTRACT: The mechanisms controlling progression of conjugative DNA processing from a preinitiation stage of specific plasmid strand cleavage at the transfer origin to a stage competent for unwinding the DNA strand destined for transfer remain obscure. Linear heteroduplex substrates containing double-stranded DNA binding sites for plasmid R1 relaxosome proteins and various regions of open duplex for TraI helicase loading were constructed to model putative intermediate structures in the initiation pathway. The activity of TraI was compared in steady-state multiple turnover experiments that measured the net production of unwound DNA as well as transesterase-catalyzed cleavage at nic. Helicase efficiency was enhanced by the relaxosome components TraM and integration host factor. The magnitude of stimul

SUBMITTER: Sut MV 

PROVIDER: S-EPMC2772500 | biostudies-literature | 2009 Nov

REPOSITORIES: biostudies-literature