A SecY homolog in Arabidopsis thaliana. Sequence of a full-length cDNA clone and import of the precursor protein into chloroplasts.
Proteins are translocated across the thylakoid membrane by two distinct pathways in higher plant chloroplasts, one of which is related to prokaryotic Sec-dependent translocation mechanisms. SecY is an essential, hydrophobic component of the membrane-bound translocase complex in bacteria, and we report here the nucleotide sequence of a full-length cDNA encoding a homolog of SecY from Arabidopsis thaliana. The predicted protein of 551 residues includes an amino-terminal extension of approximately 120 residues when compared with other SecY proteins. The deduced sequence of the mature protein, cpSecY, is 41% identical with SecY from Synechococcus and 33% identical with the Escherichia coli protein. The extension serves to target the protein into chloroplasts; transcription-translation of the cDNA yields a 58-kDa precursor protein which is imported into pea chloroplasts, processed to a product of 46 kDa, and targeted into the thylakoid membrane.
Laidler
V
V
Department of Biological Sciences, University of Warwick, Coventry, United Kingdom.
Chaddock
A M
AM
Knott
T G
TG
Walker
D
D
Robinson
C
C
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins; D001483:Base Sequence; D001692:Biological Transport; D060365:Chloroplast Proteins; D002736:Chloroplasts / Q000378:metabolism*; D003001:Cloning, Molecular; D018076:DNA, Complementary; D007425:Intracellular Membranes / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D011498:Protein Precursors / Q000378:metabolism; D000069816:SEC Translocation Channels; D017386:Sequence Homology, Amino Acid
D029681:Arabidopsis Proteins; D060365:Chloroplast Proteins; D018076:DNA, Complementary; D008565:Membrane Proteins; D010940:Plant Proteins; D011498:Protein Precursors; C000613370:SCY1 protein, Arabidopsis; D000069816:SEC Translocation Channels