title: Ni(II) and Ni(I) forms of pentaalkylamide derivatives of cofactor F430 of Methanobacterium thermoautotrophicum.
abstract: A series of pentaalkylamide forms of F430 and of its 12,13-diepimer have been generated and characterized. Carbodiimide-assisted N-hydroxysulfosuccinimide activation of all five peripheral carboxylates of the F430 macrocycle allows nucleophilic attack by a number of primary amines (RNH2, R- = CH3-, CH3CH2-, CF3CH2-, CH3(CH2)3-) generating the pentaalkylamide derivatives. The identity of each derivative has been verified by fast-atom bombardment mass spectrometry (FAB-MS). The solubility of these derivatives in aprotic organic solvents varies as the amine alkyl substituent (R-) is changed. Electrochemical measurements have shown that the Ni(II/I) reduction potentials in N,N-dimethylformamide (DMF) are approximately -1 V (Ag/AgCl). Reduction by sodium amalgam in THF generates the Ni(I) form of the F430 diepimer pentabutylamide. The visible and EPR spectra of this Ni(I) species are very similar to the corresponding spectra of Ni(I) F430M (Jaun, B. and Pfaltz, A. (1986) J. Chem. Soc. Chem. Commun. 1327-1329.).
authors.affiliation: Department of Chemistry, University of Georgia, Athens 30602.
authors.forename: C L
authors.initials: CL
authors.lastname: Hamilton
authors.forename: L
authors.initials: L
authors.lastname: Ma
authors.forename: M W
authors.initials: MW
authors.lastname: Renner
authors.forename: R A
authors.initials: RA
authors.lastname: Scott
mesh_terms: D000577:Amides / Q000138:chemical synthesis* / Q000737:chemistry; D004563:Electrochemistry; D004578:Electron Spin Resonance Spectroscopy; D019605:Euryarchaeota / Q000032:analysis*; D013058:Mass Spectrometry; D008665:Metalloporphyrins / Q000737:chemistry* / Q000302:isolation & purification; D008667:Metalloproteins / Q000737:chemistry* / Q000302:isolation & purification; D008958:Models, Molecular; D009532:Nickel / Q000737:chemistry* / Q000302:isolation & purification; D010084:Oxidation-Reduction; D012995:Solubility; D013053:Spectrophotometry
chemical_list: D000577:Amides; D008665:Metalloporphyrins; D008667:Metalloproteins; C023540:factor F430; D009532:Nickel; C057082:12,13-didehydro-F430