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Model investigations for vanadium-protein interactions: vanadium(III) compounds with dipeptides and their oxovanadium(IV) analogues
- Source :
- Journal of Biological Inorganic Chemistry, J.Biol.Inorg.Chem.
- Publication Year :
- 2001
- Publisher :
- Springer Science and Business Media LLC, 2001.
-
Abstract
- The reaction of VCl(3) with 1,10-phenanthroline and a series of dipeptides (H(2)dip), having aliphatic as well as aromatic side chains, in methyl alcohol and in the presence of triethylamine affords vanadium(III) compounds of the general formula [V(III)(dip)(MeOH)(phen)]Cl. Aerial oxidation/hydrolysis of the vanadium(III) species gives their oxovanadium(IV) analogues of the general formula [V(IV)O(dip)(phen)]. X-ray crystallographic characterization of the [V(IV)O(dip)(phen)] compounds (where dip(2-)=Gly- L-Ala, Gly- L-Val and Gly- L-Phe) revealed that the vanadium atom possesses a severely distorted octahedral coordination and is ligated to a tridentate dip(2-) ligand at the N(amine) atom, the deprotonated N(peptide) atom and one of the O(carboxylate) atoms, as well as an oxo group and two phenanthroline nitrogen atoms. Circular dichroism characterization of the V(III)/V(IV)O(2+)-dipeptide compounds revealed a strong signal for the V(IV)O(2+) species in the visible range of the spectrum, with a characteristic pattern which may be exploited to identify the N(am), N(pep) and O(car) ligation of a peptide or a protein to V(IV)O(2+) center, and a weak Cotton effect of opposite sign to their vanadium(III) analogues. The visible spectra of the V(III)-dipeptide compounds revealed two d-d bands with high intensity, thus indicating that the covalency of the metal-donor atoms is significant, i.e. the vanadium d orbitals are significantly mixed with the ligand orbitals, and this is confirmed by the low values of their Racah B parameters. The high-intensity band of the V(IV)O(2+)-dipeptide compounds at approximately 460 nm implies also a strong covalency of the metal with the equatorial donor atoms and this was supported by the EPR spectra of these compounds. Moreover, the V(III)/V(IV)O(2+)-dipeptide complexes were characterized by EPR and IR spectroscopies as well as conductivity and magnetic susceptibility measurements.
- Subjects :
- Circular dichroism
Spectrophotometry, Infrared
phenylalanine
aromatic compound
ligand
Crystallography, X-Ray
Biochemistry
law.invention
chemistry.chemical_compound
Deprotonation
phenanthroline derivative
valine
law
Electrochemistry
infrared spectroscopy
Electron paramagnetic resonance
Molecular Structure
atom
Circular Dichroism
Hydrolysis
article
1,10 phenanthroline
triethylamine
unclassified drug
priority journal
hydrolysis
oxovanadium derivative
alanine
dipeptide
Cotton effect
chemical reaction
Vanadium Compounds
oxidation
Stereochemistry
ligand binding
Phenanthroline
Gossypium hirsutum
Vanadium
chemistry.chemical_element
Inorganic Chemistry
Magnetics
protein interaction
Triethylamine
methanol
Ligand
electron spin resonance
Electron Spin Resonance Spectroscopy
X ray crystallography
Crystallography
chemistry
magnetism
Spectrophotometry, Ultraviolet
measurement
proton transport
Vanadates
Peptides
glycine
Subjects
Details
- ISSN :
- 14321327 and 09498257
- Volume :
- 7
- Database :
- OpenAIRE
- Journal :
- JBIC Journal of Biological Inorganic Chemistry
- Accession number :
- edsair.doi.dedup.....9720d2f0b2fbf4a7f144d96d3bf0b84c