Transferred nuclear Overhauser effect spectroscopy study of a peptide from the PapG pilus subunit bound by the Escherichia coli PapD chaperone

Abstract

Interaction of the Escherichia coli PapD chaperone with the synthetic peptide PapG308-314 (Thr–Met–Val–Leu–Ser–Phe–Pro), corresponding to the seven C-terminal residues of the PapG pilus subunit, was studied by transferred nuclear Overhauser effect (TRNOE) spectroscopy. The observation of cross-peaks corresponding to either intraresidue or sequential C αH/NH and C βH/NH TRNOEs and the absence of sequential NH i/NH i+1 TRNOEs indicate that the peptide binds to PapD in an extended conformation. In addition, line-broadening effects gave information of the peptide's mode of interaction with PapD. These observations were in excellent agreement with a recent crystal structure of a PapG peptide complexed with PapD.