title: X-ray absorption spectroscopic investigation of Fe(II)-peplomycin and peplomycin derivatives: the effect of axial ligation on Fe-pyrimidine back-bonding.
abstract: X-ray absorption spectroscopy (XAS) is used to study ferrous complexes of a bleomycin (BLM) congener, peplomycin (PEP), and two of its derivatives, iso-peplomycin (ISO) and depyruvamide peplomycin (DP), in which potential axial ligands have been perturbed and removed, respectively. Application of extended X-ray absorption fine structure analysis shows an elongation of the short-distance component of the first coordination sphere in DP and ISO relative to PEP. The XAS pre-edge intensity concomitantly decreases with increased axial perturbation. The short-distance component of PEP is correlated to the Fe-pyrimidine bond and is related to the amount of pi-back-bonding. Thus, the XAS analysis of these complexes provides structural information relevant to their differences in O2 reactivity.
authors.affiliation: Department of Chemistry, Stanford University, Stanford, California 94305, USA.
authors.forename: Erik C
authors.initials: EC
authors.lastname: Wasinger
authors.forename: Loeb
authors.initials: L
authors.lastname: Zaleski
authors.forename: Britt
authors.initials: B
authors.lastname: Hedman
authors.forename: Keith O
authors.initials: KO
authors.lastname: Hodgson
authors.forename: Edward I
authors.initials: EI
authors.lastname: Solomon
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry; D001761:Bleomycin / Q000031:analogs & derivatives* / Q000737:chemistry*; D005296:Ferrous Compounds / Q000737:chemistry; D007501:Iron / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry; D017663:Peplomycin / Q000031:analogs & derivatives / Q000737:chemistry*; D011743:Pyrimidines / Q000737:chemistry; D013057:Spectrum Analysis / Q000379:methods; D014965:X-Rays
chemical_list: D000900:Anti-Bacterial Agents; D005296:Ferrous Compounds; D011743:Pyrimidines; D001761:Bleomycin; D017663:Peplomycin; C020278:depyruvamide bleomycin; D007501:Iron; C030986:pyrimidine; D010100:Oxygen