Geometry-dependent phosphodiester hydrolysis catalyzed by binuclear copper complexes.
Two isomeric binuclear ligands PBTPA and MBTPA and their copper(II) complexes were prepared and examined for hydrolysis of a model phosphodiester substrate: bis(p-nitrophenyl)phosphate. A bell-shaped pH vs rate profile, which is in agreement with one mechanism proposed for bimetallonucleases/phosphatases, was observed for the binuclear complex of copper(II) and PBTPA. At pH 8.4, a maximum rate of 1.14 x 10(-6) s(-1)--more than 10(4)-fold over uncatalyzed reactions--was achieved. However, the analogous complex of MBTPA did not show significant rate enhancement. The binuclear complex of copper(II) and PBTPA also showed 10-fold acceleration over mononuclear complex of copper(II) and tris(2-pyridylmethyl)amine (TPA) catalyzed reaction. A phage phiX174 DNA assay showed that the complex of copper(II) and PBTPA promoted supercoiled phage phiX174 DNA relaxation under both aerobic and anaerobic conditions, in contrast to the hydrolytic inactivity of the mononuclear complex of copper(II) and TPA.
Zhu
Lei
L
Department of Chemistry, New York University, New York, New York 10003, USA.
dos Santos
Osvaldo
O
Koo
Chi Wan
CW
Rybstein
Marc
M
Pape
Louise
L
Canary
James W
JW
D002384:Catalysis; D003300:Copper / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry*; D004587:Electrophoresis, Agar Gel; D006868:Hydrolysis; D007700:Kinetics; D008024:Ligands; D008958:Models, Molecular; D015394:Molecular Structure; D009596:Nitrophenols / Q000737:chemistry; D010755:Organophosphates / Q000737:chemistry*; D010727:Phosphoric Diester Hydrolases / Q000737:chemistry; D011725:Pyridines / Q000737:chemistry
D008024:Ligands; D009596:Nitrophenols; D010755:Organophosphates; D011725:Pyridines; C431843:tris(2-pyridylmethyl)amine; C002887:bis(4-nitrophenyl)phosphate; D003300:Copper; D004247:DNA; D010727:Phosphoric Diester Hydrolases