Targeting determinants and proposed evolutionary basis for the Sec and the Delta pH protein transport systems in chloroplast thylakoid membranes.

ABSTRACT: Transport of proteins to the thylakoid lumen is accomplished by two precursor-specific pathways, the Sec and the unique Delta pH transport systems. Pathway selection is specified by transient lumen-targeting domains (LTDs) on precursor proteins. Here, chimeric and mutant LTDs were used to identify elements responsible for targeting specificity. The results showed that: (a) minimal signal peptide motifs consisting of charged N, hydrophobic H, and cleavage C domains were both necessary and sufficient for pathway-specific targeting; (b) exclusive targeting to the Delta pH pathway requires a twin arginine in the N domain and an H domain that is incompatible with the Sec pathway; (c) exclusive targeting to the Sec pathway is achieved by an N domain that lacks the twin arginine, although the twi

SUBMITTER: Henry R 

PROVIDER: S-EPMC2132503 | biostudies-literature | 1997 Feb

REPOSITORIES: biostudies-literature