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Roles of the N domain of the AAA + Lon protease in substrate recognition, allosteric regulation and chaperone activity
Author(s) -
Wohlever Matthew L.,
Baker Tania A.,
Sauer Robert T.
Publication year - 2014
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.12444
Subject(s) - degron , protease , allosteric regulation , biology , proteolysis , atp hydrolysis , chaperone (clinical) , biochemistry , proteases , microbiology and biotechnology , mutant , walker motifs , plasma protein binding , enzyme , ubiquitin , ubiquitin ligase , atpase , medicine , pathology , gene
Summary Degron binding regulates the activities of the AAA + Lon protease in addition to targeting proteins for degradation. The sul20 degron from the cell‐division inhibitor SulA is shown here to bind to the N domain of E scherichia coli Lon , and the recognition site is identified by cross‐linking and scanning for mutations that prevent sul20‐peptide binding. These N ‐domain mutations limit the rates of proteolysis of model sul20‐tagged substrates and ATP hydrolysis by an allosteric mechanism. Lon inactivation of SulA in vivo requires binding to the N domain and robust ATP hydrolysis but does not require degradation or translocation into the proteolytic chamber. Lon ‐mediated relief of proteotoxic stress and protein aggregation in vivo can also occur without degradation but is not dependent on robust ATP hydrolysis. In combination, these results demonstrate that Lon can function as a protease or a chaperone and reveal that some of its ATP ‐dependent biological activities do not require translocation.