Degradation parameters of Lon AAA+ protease

Range Table - link
Organism Bacteria Escherichia coli
Reference Gur E, Sauer RT. Degrons in protein substrates program the speed and operating efficiency of the AAA+ Lon proteolytic machine. Proc Natl Acad Sci U S A. 2009 Nov 3 106(44):18503-8. doi: 10.1073/pnas.0910392106. p.18504 table 1PubMed ID19841274
Primary Source See ref 9 beneath table
Method p.18503 left column bottom paragraph:"Here, [investigators] show that degradation tags play unanticipated and highly active roles in programming the operation of the Lon machine. Swapping one degradation tag for another can substantially change the speed and energetic efficiency at which Lon degrades otherwise identical proteins. [They] present evidence that degron binding controls Lon proteolysis by altering the equilibrium distribution of distinct enzyme conformations with very different proteolytic activities."
Comments p.18503 right column bottom paragraph to p.18504 left column top paragraph:"Table 1 lists kinetic parameters for Lon degradation of peptides corresponding to the ß20 and sul20C sequences. Vmax for the sul20C peptide was much faster than for the ß20 peptide, even though both substrates were the same length and degradation of both peptides required ATP hydrolysis. Hence, the ability of different tags to control rates of Lon degradation appears to be an inherent property of the tag sequence itself. KM for Lon degradation of the sul20C peptide was approximately 10-fold higher than for sul20C-tagged unfolded titin or native titin (Table 1). This observation could be explained by the high Vmax for the peptide substrate (KM = KD + Vmax/kassn) or if there were a few additional stabilizing contacts between the unfolded or native titin substrates and Lon." Degron=a specific sequence of amino acids in a protein that directs the starting place of degradation [wikipedia].
Entered by Uri M
ID 111876