SecA homolog in protein transport within chloroplasts: evidence for endosymbiont-derived sorting.
The SecA protein is an essential, azide-sensitive component of the bacterial protein translocation machinery. A SecA protein homolog (CPSecA) now identified in pea chloroplasts was purified to homogeneity. CPSecA supported protein transport into thylakoids, the chloroplast internal membrane network, in an azide-sensitive fashion. Only one of three pathways for protein transport into thylakoids uses the CPSecA mechanism. The use of a bacteria-homologous mechanism in intrachloroplast protein transport provides evidence for conservative sorting of proteins within chloroplasts.
Plant Molecular and Cellular Biology Program, University of Florida, Gainesville 32611.
J
J
Yuan
R
R
Henry
M
M
McCaffery
K
K
Cline
D000251:Adenosine Triphosphatases / Q000378:metabolism; D001386:Azides / Q000494:pharmacology; D001426:Bacterial Proteins / Q000378:metabolism; D001483:Base Sequence; D001692:Biological Transport / Q000187:drug effects; D002352:Carrier Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D060365:Chloroplast Proteins; D002736:Chloroplasts / Q000378:metabolism*; D029968:Escherichia coli Proteins; D007425:Intracellular Membranes / Q000378:metabolism; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D008969:Molecular Sequence Data; D018532:Pisum sativum; D045322:Photosynthetic Reaction Center Complex Proteins / Q000378:metabolism*; D045332:Photosystem II Protein Complex; D010940:Plant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D010970:Plastocyanin / Q000378:metabolism*; D000069816:SEC Translocation Channels; D000081416:SecA Proteins; D019810:Sodium Azide; D013559:Symbiosis
D001386:Azides; D001426:Bacterial Proteins; D002352:Carrier Proteins; D060365:Chloroplast Proteins; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D010940:Plant Proteins; D000069816:SEC Translocation Channels; C064388:oxygen-evolving complex, 33 kDa protein; D010970:Plastocyanin; D019810:Sodium Azide; D000251:Adenosine Triphosphatases; D000081416:SecA Proteins