Poly-L-lysine activates both peptide and ATP hydrolysis by the ATP-dependent HslVU protease in Escherichia coli.
Hs1VU in E. coli is a new type of ATP-dependent protease composed of two heat shock proteins, the HslU ATPase and the HslV peptidase related to certain beta-type subunits of the 20S proteasome. Here we show that the ATP-dependent hydrolysis of N-carbobenzoxy-Gly-Gly-Leu-7-amido-4-methylcoumarin by the HslVU protease can be markedly stimulated by poly-L-lysine, that is known to activate the casein-degrading activity of the 20S proteasome. However, poly-L-lysine showed little or no effect on the peptidase activity of HslV itself. Instead, it stimulated the hydrolysis of ATP by HslU several-fold. Histone that could stimulate the ATPase activity of HslU also increased the rate of the ATP-dependent peptide hydrolysis by HslV, although to a much lesser extent than by poly-L-lysine. Thus, the poly-L-lysine-mediated increase in the ATPase activity of HslU appears to be responsible for the dramatic activation of the ATP-dependent peptide hydrolysis by HslV. These results suggest that, in the reconstituted HslVU complex, the peptide hydrolysis by HslV occurs in a tightly coupled process with the cleavage of ATP by HslU.
Yoo
S J
SJ
Department of Molecular Biology, College of Natural Sciences, Seoul National University, Korea.
Seol
J H
JH
Kang
M S
MS
Chung
C H
CH
D049069:ATP-Dependent Proteases; D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism*; D010450:Endopeptidases / Q000378:metabolism*; D004789:Enzyme Activation; D004926:Escherichia coli / Q000201:enzymology*; D006360:Heat-Shock Proteins; D006868:Hydrolysis; D011107:Polylysine / Q000378:metabolism*; D011485:Protein Binding; D012697:Serine Endopeptidases
D006360:Heat-Shock Proteins; D011107:Polylysine; D000255:Adenosine Triphosphate; D010450:Endopeptidases; D049069:ATP-Dependent Proteases; D012697:Serine Endopeptidases; D000251:Adenosine Triphosphatases