Mapping of the signal peptide-binding domain of Escherichia coli SecA using Forster resonance energy transfer

Forster resonance energy transfer methodology was employed to map the location of the SecA signal peptide-binding domain using a collection of functional monocysteine SecA mutants and alkaline phosphatase signal peptides labeled with appropriate donor-acceptor fluorophores. The identified domain region by FRET was found to be located at a multidomain interface within the heart of SecA, surrounded by and potentially responsive to domains important for binding nucleotide, mature portions of the preprotein, and the SecYEG channel.