Bdellovibrio bacteriovorus synthesizes an OmpF-like outer membrane protein during both axenic and intraperiplasmic growth

Outer membrane preparations of Bdellovibrio bacteriovorus grown intraperiplasmically on Escherichia coli containing OmpF were prepared by the Triton X-100 procedure of Schnaitman (J. Bacteriol. 108:545-552, 1971). They contained a protein that migrated to almost the same position as E. coli OmpF in sodium dodecyl sulfate-acrylamide gradient gel electrophoresis and to the same position as E. coli OmpF when urea was incorporated into the gel. The mobility of this protein increased relative to that of OmpC in urea-containing gels as does E. coli OmpF. However, the same protein was also produced during axenic growth and during intraperiplasmic growth on prey lacking OmpF. The peptide profile generated by partial proteolysis of this protein showed no homology to that produced from E. coli OmpF. We conclude that B. bacteriovorus synthesizes an OmpF-like protein. Previous claims that the bdellovibrio incorporates an intact E. coli OmpF are not consistent with these observations.