title: [Role of the α-helical domains in the functioning of ATP-dependent Lon protease of Escherichia coli].
abstract: Homooligomeric ATP-dependent LonA proteases are bifunctional enzymes belonging to the superfamily of AAA+ proteins. Their subunits are formed by five successively connected domains: N-terminal (N), α-helical (HI(CC)), nucleotide binding (NB), the second α-helical (H) and proteolytic (P). The presence of the inserted HI(CC) domain defines the uniqueness of LonA proteases among AAA+ proteins. The role of α-helical domains in the LonA protease functioning is investigated on the example of E. coli Lon protease (Ec-Lon). A comparative study of properties of the intact Ec-Lon and its mutants of Lon-R164A and Lon-R542A with the substitutions of arginine residues located in similar positions in the HI(CC) and H domains is carried out. The H domain is shown to play a crucial role for the ATP hydrolysis and enzyme binding to the target protein. HI(CC) domain does not have a fundamental significance for the catalytic properties of the enzyme. However, it affects the functioning of Lon ATPase and peptidase sites and is involved in maintaining the enzyme stability. The participation of HI(CC) domain in formation of the spatial structures of LonA proteases and/or formation of their complexes with DNA is suggested.
authors.forename: A G
authors.initials: AG
authors.lastname: Andrianova
authors.forename: A M
authors.initials: AM
authors.lastname: Kudzhaev
authors.forename: O V
authors.initials: OV
authors.lastname: Serova
authors.forename: N I
authors.initials: NI
authors.lastname: Dergousova
authors.forename: T V
authors.initials: TV
authors.lastname: Rotanova
mesh_terms: D049069:ATP-Dependent Proteases / Q000737:chemistry*; D000255:Adenosine Triphosphate / Q000737:chemistry; D000595:Amino Acid Sequence; D004268:DNA-Binding Proteins / Q000737:chemistry; D004926:Escherichia coli / Q000201:enzymology*; D029968:Escherichia coli Proteins / Q000737:chemistry*; D006868:Hydrolysis; D016297:Mutagenesis, Site-Directed; D049070:Protease La / Q000737:chemistry*; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary
chemical_list: D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D000255:Adenosine Triphosphate; D049069:ATP-Dependent Proteases; C483567:Lon protein, E coli; D049070:Protease La