Rapid topology mapping of Escherichia coli inner-membrane proteins by prediction and PhoA/GFP fusion analysis

We present an approach that allows rapid determination of the topology of Escherichia coli inner-membrane proteins by a combination of topology prediction and limited fusion-protein analysis. We derive new topology models for 12 inner-membrane proteins: MarC, PstA, TatC, YaeL, YcbM, YddQ, YdgE, YedZ, YgjV, YiaB, YigG, and YnfA. We estimate that our approach should make it possible to arrive at highly reliable topology models for roughly 10% of the approximately 800 inner-membrane proteins thought to exist in E. coli.