title: Conformational changes of arginine kinase induced by photochemical release of nucleotides from caged nucleotides--an infrared difference-spectroscopy investigation.
abstract: The conformations of arginine kinase (AK) in AK x Mg x ADP, AK x Mg x ATP, AK x Mg x ADP x NO3-, AK x Mg x ADP x Arg and AK x Mg x ADP x NO3- x Arg complexes were investigated by measuring their reaction-induced infrared difference spectra (RIDS). The photochemical release of ATP from ATP[Et(PhNO2)] and of ADP from ADP[Et(PhNO2)] produced distinct RIDS of AK complexes, suggesting that binding of ADP and ATP promoted different structural alterations of the enzyme active-site. Small infrared changes in the amide-I region were observed, indicating that about 5-10 amino acid residues were involved in the nucleotide-binding site. These infrared changes were due to the structural alteration of the peptide backbone caused by the nucleotide-binding and to the coupling effects between the nucleotide-binding site and the other substrate (Arg or NO3-)-binding site. ATP binding to AK (as well as ADP-binding to AK in the presence of NO3-) induced protonation of a carboxylate group of Asp or Glu, as evidenced by the appearance of the 1733-cm(-1) band, which was not observed with the AK x Mg x ADP, AK x Mg x ADP x Arg and AK x Mg x ADP x NO3- x Arg complexes. The RIDS of the AK x Mg x ADP x NO3- x Arg complex showed new infrared bands at 1622 cm(-1) (negative) and at 1613 cm(-1) (positive), which were not seen in the RIDS of other complexes (without NO3- or/and Arg). In the transition-state-analog complex of AK, no protonation of the carboxylate residue (Asp or Glu) was observed, and the binding site of NO3- or the gamma-phosphate group of nucleotide was altered.
authors.affiliation: Université Claude Bernard Lyon I, CNRS UPRESA 5013 Laboratoire de Physico Chimie Biologique, France.
authors.forename: C
authors.initials: C
authors.lastname: Raimbault
authors.forename: F
authors.initials: F
authors.lastname: Besson
authors.forename: R
authors.initials: R
authors.lastname: Buchet
mesh_terms: D000244:Adenosine Diphosphate / Q000031:analogs & derivatives / Q000528:radiation effects; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000528:radiation effects; D000595:Amino Acid Sequence; D000818:Animals; D001122:Arginine Kinase / Q000737:chemistry* / Q000235:genetics; D001665:Binding Sites / Q000235:genetics; D066298:In Vitro Techniques; D008274:Magnesium; D008969:Molecular Sequence Data; D008121:Nephropidae / Q000201:enzymology / Q000235:genetics; D009566:Nitrates; D009578:Nitrobenzenes / Q000528:radiation effects; D010777:Photochemistry; D011487:Protein Conformation
chemical_list: D009566:Nitrates; D009578:Nitrobenzenes; C101520:P(2)-(1-(2-nitrophenyl)ethyl) ADP; D000244:Adenosine Diphosphate; C029273:P(3)-1-(2-nitro)phenylethyladenosine 5'-triphosphate; D000255:Adenosine Triphosphate; C031618:sodium nitrate; D001122:Arginine Kinase; D008274:Magnesium