CpxA (Conjugative Plasmid Expression) is the 458 amino acid protein, a bacterial inner membrane histidine protein kinase, responsible for sensing misfolded proteins in the periplasm. It is part of CpxA/CpxR two component signal transduction system, where CpxR is the cognate response regulator. In sensing bacterial envelope stress, the Cpx pathway regulates the production of a number of periplasmic folding and trafficking factors to maintain outer membrane integrity. It is also responsible for global control of virulence factor expression. Alternative name: Integral membrane sensor signal transduction histidine kinase.

Recombinant CpxA (residues 26 to 168) over-expressed as a N-terminal fusion with His(x6)-tag, which was removed prior to immunization. The antigen originates from enteropathogenic Yersinia pseudotuberculosis YPIII; B1JQV1, NCBI annotated locus tag YPK_4133.

store lyophilized/reconstituted at -20°C; once reconstituted make aliquots to avoid repeated freeze-thaw cycles. Please, remember to spin tubes briefly prior to opening them to avoid any losses that might occur from lyophilized material adhering to the cap or sides of the tubes.

Plant protein extraction buffer

Secondary antibodies

The strains were grown in LB broth until late stationary phase (absorbance at 600nm of ~1.5). To avoid interference from cross-reacting bands, aim to maximize protein separation with the region of 35 to 55 kDa. CpxA could be routinely detected from a 20 µL of sample that was derived from 1ml of pelleted bacteria resuspended in 200 µl of 1x loading buffer. Re-use of diluted working strength antibody is not recommended.