Publication Date:
2019
Description:
〈sec〉〈st〉Synopsis〈/st〉〈p〉〈textbox textbox-type="graphic"〉〈p〉〈inline-fig〉〈/inline-fig〉〈/p〉〈/textbox〉〈/p〉
〈p〉How AAA ATPases harness energy from ATP to promote directional translocation of polypeptides across membranes is poorly understood. Single-molecule FRET reveals that bacterial SecA uses ATP hydrolysis to push a polypeptide segment into the SecY channel, and phosphate release to slide it through the SecA-SecY complex.〈/p〉
〈p〉 〈l type="unord"〉〈li〉〈p〉SecA two-helix finger and clamp domains move upon ATP binding, hydrolysis and phosphate release.〈/p〉〈/li〉
〈li〉〈p〉ATP binding moves the two-helix finger towards the SecY channel, causing insertion of the first polypeptide segment into the channel.〈/p〉〈/li〉
〈li〉〈p〉Upon ATP hydrolysis, finger retraction and clamp domain closure around the translocating polypeptide ensure the translocation progress.〈/p〉〈/li〉
〈li〉〈p〉Clamp opening induced by phosphate release permits passive sliding of the polypeptide in either direction.〈/p〉〈/li〉〈/l〉 〈/p〉〈/sec〉
Print ISSN:
0261-4189
Electronic ISSN:
1460-2075
Topics:
Biology
,
Medicine
