Detection of the KdpD-Usp chimeras. E. coli strain LMG194 was transformed with the pBD plasmids encoding the different KdpD-Usp chimeras or the empty vector pBAD18 (vector control). Overproduction of the indicated proteins was achieved by addition of 0.2% (w/v) arabinose. Cells were harvested in the mid-logarithmic growth phase, disrupted by addition of SDS-sample buffer , and subjected to a 10% SDS-gel. The KdpD chimeras were detected by immunoblotting with polyclonal antibodies against KdpD.