Cell envelope proteins in bacteria are typically difficult to characterize due to their low abundance, poor solubility, and the problematic isolation of pure surface fraction with only minimal contamination. Here we describe a method for cell membrane fractionation followed by mass spectrometry-based proteomics to analyze and determine protein abundance in bacterial membranes.
Keywords: Cell fractionation; Gel-free; Gram-negative cell envelope; Membrane proteins; MudPIT; Outer membrane.