The full precursor of the 33 kDa oxygen-evolving complex protein of wheat is exported by Escherichia coli and processed to the mature size.

A full-length cDNA encoding the precursor of the lumenal 33 kDa oxygen-evolving complex protein from wheat was inserted into a prokaryotic expression vector. Cell-free transcription-translation of this construct generates a precursor protein of the correct size. However, when expressed in Escherichia coli, the protein is quantitatively exported into the periplasm and processed to the mature size. The results indicate that the thylakoid transfer sequence of this precursor can function as an internal E. coli export signal.