N-peptide, WEYIPNV, is a heptapeptide selected from a phage library that binds the gram-negative, periplasmic chaperone protein chaperone SurA with micromolar affinity. N-peptide (WEYIPNV) recognition is conferred by the first peptidyl-prolyl isomerase (PPIase) domain of SurA and N-peptide and SurA bind to each other in a 1:1 ratio. SurA is involved in the proper folding of outer membrane porins (OMPs), which protect bacteria against toxins in the extracellular environment and novel SurA inhibitors have the potential to overcome antibiotic resistance. Rhodamine-labeled N-peptide WEYIPNV can be used for a competitive assay for inhibitors of SurA.
