Evidence for the location of OprM in the Pseudomonas aeruginosa outer membrane

OprM with a Mr of 49 K is associated with the multidrug resistance of Pseudomonas aeruginosa. Detergent fractionation of bacterial cells has demonstrated that OprM is located in the outer membrane from which it sediments with the other major outer membrane proteins. In this study we have determined the location of OprM as the P. aeruginosa outer membrane. Western immunoblots of cell fractions, obtained by sucrose density gradient centrifugation of whole cell lysates, were probed with an OprM-specific murine polyclonal antiserum.