Interaction of the motor protein SecA and the bacterial protein translocation channel SecYEG in the absence of ATP.

ABSTRACT: Translocation of many secretory proteins through the bacterial plasma membrane is facilitated by a complex of the SecYEG channel with the motor protein SecA. The ATP-free complex is unstable in detergent, raising the question how SecA may perform several rounds of ATP hydrolysis without being released from the membrane embedded SecYEG. Here we show that dual recognition of (i) SecYEG and (ii) vicinal acidic lipids confers an apparent nanomolar affinity. High-speed atomic force microscopy visualizes the complexes between monomeric SecA and SecYEG as being stable for tens of seconds. These long-lasting events and complementary shorter ones both give rise to single ion channel openings of equal duration. Furthermore, luminescence resonance energy transfer reveals two conformations of the SecY

SUBMITTER: Winkler K 

PROVIDER: S-EPMC9418451 | biostudies-literature | 2020 Aug

REPOSITORIES: biostudies-literature