title: Protein substrates and heat shock reduce the DNA-binding ability of Escherichia coli Lon protease.
abstract: Interaction between the fusion protein MBP-Lon, formed by maltose-binding protein and Lon protease, and the plasmid pBR322 was studied to clarify the DNA-binding behavior of the Lon protease. Since the MBP-Lon fusion protein that was bound to the plasmid was strongly adsorbed by amylose resin, complex formation and dissociation were determined by quantifying the unadsorbed plasmid using agarose gel electrophoresis. The autolysis of MBP-Lon fusion protein was suppressed when the protein was bound to the plasmid. The plasmid was completely dissociated from MBP-Lon fusion protein by the addition of the protein substrates of Lon protease (i.e. alpha-casein and denatured bovine serum albumin). In addition, at high temperatures, MBP-Lon fusion protein lost its plasmid-binding ability, although it fully retained ATP-dependent protease activity. These results suggest that Lon protease loses DNA-binding ability when cells are exposed to abnormal conditions and the amount of damaged proteins increases. On the other hand, DNA probably plays an important role in controlling the Lon protease activity in cells under normal conditions by entrapping the enzyme.
authors.affiliation: Department of Applied Chemistry, Faculty of Engineering, Kyushu Institute of Technology, Kitakyushu, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Sonezaki
authors.forename: K
authors.initials: K
authors.lastname: Okita
authors.forename: T
authors.initials: T
authors.lastname: Oba
authors.forename: Y
authors.initials: Y
authors.lastname: Ishii
authors.forename: A
authors.initials: A
authors.lastname: Kondo
authors.forename: Y
authors.initials: Y
authors.lastname: Kato
mesh_terms: D018528:ATP-Binding Cassette Transporters; D049069:ATP-Dependent Proteases; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001667:Binding, Competitive; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D002364:Caseins / Q000494:pharmacology*; D002417:Cattle; D004269:DNA, Bacterial / Q000378:metabolism*; D004587:Electrophoresis, Agar Gel; D004789:Enzyme Activation; D004926:Escherichia coli / Q000201:enzymology*; D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D006358:Hot Temperature; D058619:Maltose-Binding Proteins; D009004:Monosaccharide Transport Proteins; D010957:Plasmids / Q000235:genetics; D049070:Protease La; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012697:Serine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D012710:Serum Albumin, Bovine / Q000494:pharmacology*
chemical_list: D018528:ATP-Binding Cassette Transporters; D002352:Carrier Proteins; D002364:Caseins; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins; D058619:Maltose-Binding Proteins; D009004:Monosaccharide Transport Proteins; D011993:Recombinant Fusion Proteins; C461599:maltose transport system, E coli; D012710:Serum Albumin, Bovine; D000255:Adenosine Triphosphate; D049069:ATP-Dependent Proteases; D012697:Serine Endopeptidases; C483567:Lon protein, E coli; D049070:Protease La