Distinct quaternary structures of the AAA+ Lon protease control substrate degradation
Year: 2013
Type: article
Abstract: Lon is an ATPase associated with cellular activities (AAA+) protease that controls cell division in response to stress and also degrades misfolded and damaged proteins. Subunits of Lon are known to assemble into ring-shaped homohexamers that enclose an internal degradation chamber. Here, we demonstrate that hexamers of Escherichia coli Lon also interact to form a dodecamer at physiological protein concentrations. Electron microscopy of this dodecamer reveals a prolate structure with the protease chambers at the distal ends and a matrix of N domains forming an equatorial hexamer-hexamer interface, with portals of ∼45 Å providing access to the enzyme lumen. Compared with hexamers, Lon dodecamers are much less active in degrading large substrates but equally active in degrading small substrates. Our results support a unique gating mechanism that allows the repertoire of Lon substrates to be tuned by its assembly state.
Authors: Ellen F. Vieux, Matthew L. Wohlever, James Z. Chen, Robert T. Sauer, Tania A. Baker
Language: English
Topic: Heat shock proteins research
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W2099111412