Thirty-eight C-terminal amino acids of the coupling protein TraD of the F-like conjugative resistance plasmid R1 are required and sufficient to confer binding to the substrate selector protein TraM.

ABSTRACT: Coupling proteins (CPs) are present in type IV secretion systems of plant, animal, and human pathogens and are essential for DNA transfer in bacterial conjugation systems. CPs connect the DNA-processing machinery to the mating pair-forming transfer apparatus. In this report we present in vitro and in vivo data that demonstrate specific binding of CP TraD of the IncFII R1 plasmid transfer system to relaxosomal protein TraM. With overlay assays and enzyme-linked immunosorbent assays we showed that a truncated version of TraD, termed TraD11 (DeltaN155), interacted strongly with TraM. The apparent TraD11-TraM association constant was determined to be 2.6 x 10(7) liters/mol. Electrophoretic mobility shift assays showed that this variant of TraD also strongly bound to TraM when it was in complex

SUBMITTER: Beranek A 

PROVIDER: S-EPMC522193 | biostudies-literature | 2004 Oct

REPOSITORIES: biostudies-literature