Background: Enterococcus faecalis is a significant nosocomial pathogen which is able to survive in diverse environments and resist killing with antimicrobial therapies. The expression of cell membrane proteins play an important role in how bacteria respond to environmental stress. As such, the capacity to identify and study membrane protein expression is critical to our understanding of how specific proteins influence bacterial survival.  Here we describe a combined approach to identify membrane proteins of E. faecalis ATCC V583 using membranes fractionated by either 1D-SDS-PAGE or membrane shaving, coupled with LC-ESI mass spectrometry.

Results: Two hundred and two membrane-associated proteins were identified which represents approximately 24 percent of the predicted membrane-associated proteome. 170 were isolated using 1D-SDS-PAGE and 68 with membrane shaving, with 36 proteins being common to both techniques. Ninety seven percent of the proteins identified by membrane shaving were membrane associated with the majority being integral membrane proteins (89%). The majority of proteins identified with known physiology are involved with transportation across the membrane.

Conclusion: The combined 1D-SDS-PAGE and membrane shaving approach has produced the greatest number of membrane proteins identified from E. faecalis to date.