Identification of two GTP-binding proteins in the chloroplast protein import machinery.
Two of four proteins that associated with translocation intermediates during protein import across the outer chloroplast envelope membrane were identified as guanosine triphosphate (GTP)-binding proteins. Both proteins are integral membrane proteins of the outer chloroplast membrane, and both are partially exposed on the chloroplast surface where they were accessible to thermolysin digestion. Engagement of the outer membrane's import machinery by an import substrate was inhibited by slowly hydrolyzable or non-hydrolyzable GTP analogs. Thus, these GTP-binding proteins may function in protein import into chloroplasts.
Kessler
F
F
Laboratory of Cell Biology, Howard Hughes Medical Institute, Rockefeller University, New York, NY 10021.
Blobel
G
G
Patel
H A
HA
Schnell
D J
DJ
D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D001483:Base Sequence; D001692:Biological Transport; D002736:Chloroplasts / Q000737:chemistry / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000378:metabolism; D007425:Intracellular Membranes / Q000737:chemistry / Q000378:metabolism*; D008565:Membrane Proteins / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D020559:Monomeric GTP-Binding Proteins; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism*; D016415:Sequence Alignment
D008565:Membrane Proteins; D010940:Plant Proteins; C090341:IAP35 protein, Pisum sativum; D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate; D019204:GTP-Binding Proteins; D020559:Monomeric GTP-Binding Proteins