Targeting signals for a bacterial Sec-independent export system direct plant thylakoid import by the delta pH pathway.
Preproteins targeted to the Sec-independent protein transport systems of plant thylakoids and of bacteria both have unusual transfer peptides bearing a consensus twin-arginine motif. Possible mechanistic similarity between the two Sec-independent transport pathways was investigated by assessing the ability of bacterial twin-arginine transfer peptides to direct thylakoid import. High efficiency import was observed. This process was demonstrated to occur specifically via the Sec-independent deltapH pathway and to depend on an intact twin-arginine motif on the transfer peptide. These results provide strong evidence for the operation of mechanistically related Sec-independent protein transport pathways in chloroplasts and bacteria.
Centre for Metalloprotein Spectroscopy and Biology, University of East Anglia, Norwich, UK.
M
M
Wexler
E G
EG
Bogsch
R B
RB
Klösgen
T
T
Palmer
C
C
Robinson
B C
BC
Berks
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000378:metabolism*; D001692:Biological Transport; D006863:Hydrogen-Ion Concentration; D007425:Intracellular Membranes / Q000378:metabolism; D008969:Molecular Sequence Data; D010944:Plants / Q000378:metabolism*; D015398:Signal Transduction
D001426:Bacterial Proteins