Protein translocon at the Arabidopsis outer chloroplast membrane

被引:51
作者
Hiltbrunner, A [1 ]
Bauer, J [1 ]
Alvarez-Huerta, M [1 ]
Kessler, F [1 ]
机构
[1] Swiss Fed Inst Technol, Inst Plant Sci, Plant Physiol & Biochem Grp, CH-8092 Zurich, Switzerland
来源
BIOCHEMISTRY AND CELL BIOLOGY-BIOCHIMIE ET BIOLOGIE CELLULAIRE | 2001年 / 79卷 / 05期
关键词
Arabidopsis; genetics; chloroplast; protein import;
D O I
10.1139/bcb-79-5-629
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Chloroplasts are organelles essential for the photoautotrophic growth of plants. Their biogenesis from undifferentiated proplastids is triggered by light and requires the import of hundreds of different precursor proteins from the cytoplasm. Cleavable N-terminal transit sequences target the precursors to the chloroplast where translocon complexes at the outer (Toc complex) and inner (Tic complex) envelope membranes enable their import. In pea, the Toc complex is trimeric consisting of two surface-exposed GTP-binding proteins (Toc159 and Toc34) involved in precursor recognition and Toc75 forming an aequeous protein-conducting channel. Completion of the Arabidopsis genome has revealed an unexpected complexity of predicted components of the Toc complex in this plant model organism: four genes encode homologs of Toc159, two encode homologs of Toc34, but only one encodes a likely functional homolog of Toc75. The availability of the genomic sequence data and powerful molecular genetic techniques in Arabidopsis set the stage to unravel the mechanisms of chloroplast protein import in unprecedented depth.
引用
收藏
页码:629 / 635
页数:7
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