Phophorylmimetic study.

<p>A CipB reporter strain in the Δ<i>comE</i> deletion background was transformed with plasmids carrying the coding sequence of the natural <i>comE</i> (ComE nat.), the coding sequence of <i>comE</i> under the control of the strong lactococcal P23 promoter (P23-ComE), or the mutant genes ComE D60E (mimicking stable phorphorylation) and ComE D60A (no phosphorylation possible). A strain transformed with the empty vector (pIB166) was used as negative control. All strains were grown in THBY and fluorescence microscopy was performed 1 h after addition of CSP. Overlays of phase contrast and green fluorescence microscopic images are shown. The right column shows the un-induced controls.