"
Team:Paris/Addressing overview exportsystem
From 2009.igem.org
(→Overview) |
(→A. Export system) |
||
| Line 17: | Line 17: | ||
===A. Export system=== | ===A. Export system=== | ||
| - | In this | + | Introduction |
| + | |||
| + | The Tat (twin-arginine translocation) system is a bacterial protein export pathway with the remarkable ability to transport folded proteins across the cytoplasmic membrane. Preproteins are directed to the Tat pathway by signal peptides that bear a characteristic sequence motif, which includes consecutive arginine residues. | ||
| + | The most remarkable characteristic of the Tat pathway is that it apparently functions to transport folded proteins of variable dimensions across the cytoplasmic membrane, a feat that must be achieved without rendering the membrane freely permeable to protons and other ions. | ||
| + | In most cases, the substrates of this pathway are proteins that bind one of a range of cofactors in the cytoplasm and are thus folded before export. Some cofactorless proteins may also be transported by the Tat pathway, probably because they either require cytoplasmic factors for folding or fold too rapidly or tightly for transport by the Sec apparatus. | ||
| + | Recent work has shown that the bacterial Tat system is very closely related to the DeltapH-dependent protein import pathway of the plant chloroplast thylakoid membrane. The bacterial and plant systems do, however, differ in the treatment of precursors before the transport step because, in contrast to well-characterized delta pH-dependent pathway precursors, bacterial Tat substrates has to be co-ordinates with cofactor insertion. | ||
Revision as of 16:21, 11 October 2009
iGEM > Paris > Adressing > Export & ClyA > Export systems
A. Export system
Introduction
The Tat (twin-arginine translocation) system is a bacterial protein export pathway with the remarkable ability to transport folded proteins across the cytoplasmic membrane. Preproteins are directed to the Tat pathway by signal peptides that bear a characteristic sequence motif, which includes consecutive arginine residues. The most remarkable characteristic of the Tat pathway is that it apparently functions to transport folded proteins of variable dimensions across the cytoplasmic membrane, a feat that must be achieved without rendering the membrane freely permeable to protons and other ions. In most cases, the substrates of this pathway are proteins that bind one of a range of cofactors in the cytoplasm and are thus folded before export. Some cofactorless proteins may also be transported by the Tat pathway, probably because they either require cytoplasmic factors for folding or fold too rapidly or tightly for transport by the Sec apparatus.
Recent work has shown that the bacterial Tat system is very closely related to the DeltapH-dependent protein import pathway of the plant chloroplast thylakoid membrane. The bacterial and plant systems do, however, differ in the treatment of precursors before the transport step because, in contrast to well-characterized delta pH-dependent pathway precursors, bacterial Tat substrates has to be co-ordinates with cofactor insertion.
