title: Investigation of the interaction of iron(III) complexes with dAMP by ESI-MS, MALDI-MS and potentiometric titration: insights into synthetic nuclease behavior.
abstract: We report herein the characterization by electrospray ionization (ESI) mass spectrometry (MS), matrix assisted laser desorption ionization (MALDI-MS) and potentiometric titration of three iron(III) compounds: [Fe(III)(HPClNOL)Cl2]·NO3 (1), [Cl(HPClNOL)Fe(III)-(μ-O)-Fe(III)(HPClNOL)Cl]·Cl2·H2O (2) and [(SO4)(HPClNOL)Fe(III)-(μ-O)-Fe(III)(HPClNOL)(SO4)]·6H2O (3), where HPClNOL= 1-(bis-pyridin-2-ylmethyl-amino)-3-chloropropan-2-ol). Despite the fact that the compounds have distinct structures in solid state and non-buffered solution, all compounds present similar ESI and MALDI mass spectra in a buffered medium (pH 7.0). At this pH, the species [(PClNOL)Fe(III)-(μ-O)-Fe(III)(PClNOL)](2+) (m/z 354) was observed for all the compounds under investigation. Potentiometric titration confirms a similar behavior for all compounds, indicating that the dihydroxo form [(OH)(HPClNOL)Fe(III)-(μ-O)-Fe(III)(HPClNOL)(OH)](2+) is the major species at pH 7.0, for all the compounds. The products of the interaction between compounds (1), (2) and (3) and dAMP (2'-deoxyadenosine-5'-monophosphate) in a buffered medium (pH 7.0) were identified by MALDI-MS/MS. The fragmentation data obtained by MS/MS allow one to identify the nature of the interaction between the iron(III) compounds and dAMP, revealing the direct interaction between the iron center and phosphate groups.
authors.affiliation: Laboratorio de Ciências Químicas, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, 28013-602, RJ, Brazil. chris@pq.cnpq.br.
authors.forename: Christiane
authors.initials: C
authors.lastname: Fernandes
authors.forename: Rafaela
authors.initials: R
authors.lastname: Oliveira Moreira
authors.forename: Leonardo M
authors.initials: LM
authors.lastname: Lube
authors.forename: Adolfo
authors.initials: A
authors.lastname: Horn
authors.forename: Bruno
authors.initials: B
authors.lastname: Szpoganicz
authors.forename: Stacy
authors.initials: S
authors.lastname: Sherrod
authors.forename: David H
authors.initials: DH
authors.lastname: Russell
mesh_terms: D003838:Deoxyadenine Nucleotides / Q000737:chemistry*; D005290:Ferric Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D015394:Molecular Structure; D011199:Potentiometry; D021241:Spectrometry, Mass, Electrospray Ionization; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D003838:Deoxyadenine Nucleotides; D005290:Ferric Compounds; C012873:2'-deoxy-5'-adenosine monophosphate