Allosterically modulated molecular machines mediate many of the key processes in all forms of life. The Sec translocon, a membrane bound protein complex, is the principal route for the efficient transport of heterogeneous polypeptides across or into lipid bilayers. The bacterial translocon consists of two main parts, a cytosolic ATPase SecA and membrane channel SecYEG. Based on our group’s recent findings we propose that the Sec translocon is a novel type of stochastically coupled hybrid molecular machine, where the processive SecA steers the energy landscape of a stochastic SecYEG channel allosterically dependent on nucleotide state. We present a research project to map the full allosteric network regulating different stages of protein translocation in the Sec complex using a combination of single-molecule and in silico methods.
Fessl Tomáš Ph.D.