20211011 Chang CI paper photo

Molecular basis for ATPase-powered substrate translocation by the Lon AAA+ protease

Molecular basis for ATPase-powered substrate translocation by the Lon AAA+ protease

Journal of Biological Chemistry. 2021 Oct; 297(4), 101239.
doi: 10.1016/j.jbc.2021.101239

閱讀文章

Li S, Hsieh KY, Su SC, Pintilie GD, Zhang K, Chang CI

摘要

The Lon AAA+ (adenosine triphosphatases associated with diverse cellular activities) protease (LonA) converts ATP-fuelled conformational changes into sufficient mechanical force to drive translocation of a substrate into a hexameric proteolytic chamber. To understand the structural basis for the substrate translocation process, we determined the cryo-electron microscopy (cryo-EM) structure of Meiothermus taiwanensis LonA (MtaLonA) in a substrate-engaged state at 3.6 Å resolution. Our data indicate that substrate interactions are mediated by the dual pore-loops of the ATPase domains, organized in spiral staircase arrangement from four consecutive protomers in different ATP-binding and hydrolysis states. However, a closed AAA+ ring is maintained by two disengaged ADP-bound protomers transiting between the lowest and highest position. This structure reveals a processive rotary translocation mechanism mediated by LonA-specific nucleotide-dependent allosteric coordination among the ATPase domains, which is induced by substrate binding.