Effect of lrp mutations on conjugal plasmid transfer Together , the results suggest that Lrp might act as an activator of conjugal plasmid transfer .
This magnification of the difference in the absence of fertility inhibition further supports the model that Lrp acts as an activator of pSLT plasmid transfer : a FinO-plasmid is no longer derepressed when an lrp mutation reduces traJ transcription .
When leucine was added to the MOPS culture , the level of lrp-gfp expression increased by between 1.5-and 2-fold , provided the Lrp protein was present ; leucine did not have this effect in the lrp knockout mutant .