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Evidence for a loop mechanism of protein transport by the thylakoid Delta pH pathway
Author(s) -
Fincher Vivian,
McCaffery Michael,
Cline Kenneth
Publication year - 1998
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(98)00066-0
Subject(s) - thylakoid , twin arginine translocation pathway , chemistry , biophysics , transport protein , delta , biochemistry , membrane , biology , chloroplast , physics , gene , astronomy
The thylakoid Delta pH pathway is a protein transport system with unprecedented characteristics. To investigate its mechanism, the topology of precursor insertion was determined. A fusion protein comprising a large polypeptide domain fused to the amino terminus of pOE17 (a Delta pH pathway precursor) was efficiently processed by thylakoid membranes. The amino terminus, including the targeting peptide, remained on the cis side of the membrane. Mature OE17 was transported to the lumen. These experiments demonstrate that Delta pH directed precursors enter the thylakoid membrane in a loop, implying that the Delta pH pathway has evolved from an export‐type protein translocation system.