title: Hydrolytic cleavage of double-strand DNA by the water-soluble dicobalt(III) complexes of 1,4,7-triazacyclononane-N-acetate.
abstract: Three water-soluble dicobalt(III) complexes, [Co(2)L(2)(micro-OH)(2)](ClO(4))(2).5H(2)O (1), [Co(2)L(2)(micro-OH)(2)](ClO(4))(2).CH(3)OH.H(2)O(2); [Co(2)L(2)(micro-OH)(2)](ClO(4))(2).4H(2)O(3) (L=1,4,7-triazacyclononane-N-acetate monoanion), were prepared to serve as nuclease mimics. The complexes were characterized by X-ray, IR and UV-vis spectroscopy as well as ESI-MS. Three complexes exhibit similar structures, just with different solvent molecules. The electrospray mass spectrum of 1 in solution indicates that dinuclear ion [Co(2)L(2)(micro-OH)(2)-H(+)] (+) (4) is the active species. In the absence of any reducing agent, the complexes cleave plasmid pBR322 DNA was performed and its hydrolytic mechanism was demonstrated with radical scavengers, anaerobic reaction and T4 ligase. The kinetic aspects of DNA cleavage under pseudo- or true-Michaelis-Menten conditions are also detailed, kinetic parameters (k(cat), K(M)) were calculated to be 3.57 h(-1), 6.92 x 10(-4)M; 0.28 h(-1), 1.9 x 10(-5)M for 4, respectively.
authors.affiliation: Department of Chemistry, Nankai University, Tianjin 300071, PR China.
authors.forename: Jing
authors.initials: J
authors.lastname: Qian
authors.forename: Xiaofang
authors.initials: X
authors.lastname: Ma
authors.forename: Jinlei
authors.initials: J
authors.lastname: Tian
authors.forename: Wen
authors.initials: W
authors.lastname: Gu
authors.forename: Jing
authors.initials: J
authors.lastname: Shang
authors.forename: Xin
authors.initials: X
authors.lastname: Liu
authors.forename: Shiping
authors.initials: S
authors.lastname: Yan
mesh_terms: D001372:Aza Compounds / Q000737:chemistry*; D003035:Cobalt / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry*; D053837:DNA Cleavage; D008958:Models, Molecular; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: C499747:1,4,7-trimethyl-1,4,7-triazacyclononane; D001372:Aza Compounds; D003035:Cobalt; D004247:DNA