Maurer Carlo, Panahandeh Sascha, Moser Michael, Müller Matthias
Institut für Biochemie und Molekularbiologie, ZBMZ, Universität Freiburg, Freiburg, Germany.
FEBS Lett. 2009 Sep 3;583(17):2849-53. doi: 10.1016/j.febslet.2009.07.038. Epub 2009 Jul 23.
The twin-arginine translocation (Tat) machinery is able to transport fully folded proteins across bacterial and thylakoidal membranes. Previous in vivo and in vitro studies indicated that the model Tat substrate TorA-PhoA acquires Tat-competence only if its four cysteines form disulfide bonds. We now show that removal of the last 33 amino acids of PhoA, although not affecting the formation of disulfide bonds, converts TorA-PhoA into a poor Tat substrate. This finding suggests that even incomplete folding of a substrate can interfere with transport by the Tat translocase of Escherichia coli.
双精氨酸转运（Tat）机制能够将完全折叠的蛋白质转运穿过细菌和类囊体膜。先前的体内和体外研究表明，模型Tat底物TorA-PhoA只有在其四个半胱氨酸形成二硫键时才获得Tat转运能力。我们现在表明，去除PhoA的最后33个氨基酸，虽然不影响二硫键的形成，但会将TorA-PhoA转化为一种低效的Tat底物。这一发现表明，即使底物的折叠不完全也会干扰大肠杆菌Tat转位酶的转运。
