THE CYTOPLASMIC DNA-BINDING PROTEIN TRAM BINDS TO THE INNER MEMBRANE-PROTEIN TRAD IN-VITRO

The cytoplasmic protein TraM is one of four essential gene products of the F factor which are involved in DNA transfer after mating pair for mation. TraM binds to three specific sites within the oriT region. Bes ides regulation of its own synthesis, the precise function of TraM dur ing conjugation is not yet known. In the present work, the affinity of TraM to TraD was studied in vitro by an overlay assay and by affinity chromatography. Whether the interaction between TraM and TraD causes a transient or permanent anchoring of the F factor to the site of tran sfer is discussed, A 35-kDa host membrane protein of yet unknown funct ion also shows affinity to TraM and may be involved in this anchoring process as well.