58 ABSTRACTS pa MODELING COPPER-DNA INTERACTIONS. Jose-Luis Sagripanti and LeRoy Schroeder,Q@ce of Science and Technology, CDRH, FDA, Rockville, MD 20857 This work presents data generated by computer assisted modelling of the three- dimensional interaction between copper and DNA. The computer program, Polygraf was used on a Personal IRIS 4D-25 workstation to create, display and minimize the energy of Cu(II)- and Cu(I)-DNA complexes. Possible models were ranked considering the number and geometry of coordination sites, as well as energy and molecular distortion resulting from the interactions of copper and nearby atoms. Among all bases, the interaction of copper with sites involving guanosine was favored. Comparison of the models allows us to propose a strain driven mechanism of reaction between copper and guanosine consistent with in vitro data on DNA damage mediated by copper and copper-DNA binding. p41 KINETICS OF ELECTRON-TRANSFER BETWEEN CYTOCHROME c AND MULTICOPPER OXIDASES. Take&i S&Q& College of Liberal Arts and Sciences, Kanazawa University, Kanazawa, Ishikawa 920, Japan Rate constants have been detetined for the electron-transfer (ET) reactions between reduced horse heart cytochrome c and resting RIurs vernkiferu lactase as a function of pH, ionic strength, and temperature. The second-order rate constants and activation parameters, AHSand AS* for the oxidation of reduced q&chrome c were determined. The rate constants increased with decreasing buffer concentration, indicating that the ET is realized by the electrostatic interaction (ZAZB = - 0.45) between the basic proteins. From the increase of the mte of EI’ with decreasing pH, the driving forces of the reaction were discussed. One hexametaphosphate accelerated the ET rate. The reaction of ascorbate oxidase is in progress. p42 SYNTHESES, STRUCTURES AND PROPERTIES OF COPPER(I) AND COFPER(I1) COMPLEXES OF THE NEW BINUCLEATING LIGAND 1,3=BIS[BIS (2-PYRIDYLMETHYL) AMINO] BENZENE. &&fried S&&&K, Carol Creutz and David Szalda Chemistry Department, Brookhaven National Laboratory*, Upton NY 11973 We describe the synthesis of L, [Cu2L](PF6)2, [cU2L(co)2](p&)2 and [Cu2L](ClC4)4. The complexes are characterized by crystal structums, electro- chemistry, UV/vis-spectroscopy and chemical behavior. The Cu(II) ions in [Cu2L](C104)4 are bridged by a perchlorate ion in the solid state. No hydroxylation of the benzene ring is observed after reaction of the copper(I) complex with oxygen..The binding constant for the reaction of carbon monoxide with [Cu2L](pF6)2 was measured by cyclic VOkaUUnetry. *This research was carried out at Brookhaven National Laboratory under contract DE-AC02-76CHOOO16 with the U.S. Department of Energy and supported by its Division of Chemical Sciences, Office of Basic Energy Sciences.

Kinetics of electron-transfer between cytochrome c and multicopper oxidases

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Page 1: Kinetics of electron-transfer between cytochrome c and multicopper oxidases

58 ABSTRACTS

pa MODELING COPPER-DNA INTERACTIONS. Jose-Luis Sagripanti and LeRoy Schroeder,Q@ce of Science and Technology, CDRH, FDA, Rockville, MD 20857

This work presents data generated by computer assisted modelling of the three- dimensional interaction between copper and DNA. The computer program, Polygraf was used on a Personal IRIS 4D-25 workstation to create, display and minimize the energy of Cu(II)- and Cu(I)-DNA complexes. Possible models were ranked considering the number and geometry of coordination sites, as well as energy and molecular distortion resulting from the interactions of copper and nearby atoms. Among all bases, the interaction of copper with sites involving guanosine was favored. Comparison of the models allows us to propose a strain driven mechanism of reaction between copper and guanosine consistent with in vitro data on DNA damage mediated by copper and copper-DNA binding.

p41 KINETICS OF ELECTRON-TRANSFER BETWEEN CYTOCHROME c AND MULTICOPPER OXIDASES.

Take&i S&Q& College of Liberal Arts and Sciences, Kanazawa University, Kanazawa, Ishikawa 920, Japan

Rate constants have been detetined for the electron-transfer (ET) reactions between reduced horse heart cytochrome c and resting RIurs vernkiferu lactase as a function of pH, ionic strength, and temperature. The second-order rate constants and activation parameters, AHS and AS* for the oxidation of reduced q&chrome c were determined. The rate constants increased with decreasing buffer concentration, indicating that the ET is realized by the electrostatic interaction (ZAZB = - 0.45) between the basic proteins. From the increase of the mte of EI’ with decreasing pH, the driving forces of the reaction were discussed. One hexametaphosphate accelerated the ET rate. The reaction of ascorbate oxidase is in progress.

p42 SYNTHESES, STRUCTURES AND PROPERTIES OF COPPER(I) AND COFPER(I1) COMPLEXES OF THE NEW

BINUCLEATING LIGAND 1,3=BIS[BIS (2-PYRIDYLMETHYL) AMINO] BENZENE. &&fried S&&&K, Carol Creutz and David Szalda Chemistry Department, Brookhaven National Laboratory*, Upton NY 11973 We describe the synthesis of L, [Cu2L](PF6)2, [cU2L(co)2](p&)2 and [Cu2L](ClC4)4. The complexes are characterized by crystal structums, electro- chemistry, UV/vis-spectroscopy and chemical behavior. The Cu(II) ions in [Cu2L](C104)4 are bridged by a perchlorate ion in the solid state. No hydroxylation of the benzene ring is observed after reaction of the copper(I) complex with oxygen..The binding constant for the reaction of carbon monoxide with [Cu2L](pF6)2 was measured by cyclic VOkaUUnetry.

*This research was carried out at Brookhaven National Laboratory under contract DE-AC02-76CHOOO16 with the U.S. Department of Energy and supported by its Division of Chemical Sciences, Office of Basic Energy Sciences.