The reaction of hydrogen atoms with methionine residues: A model of reductive radical stress causing tandem protein-lipid damage.
The occurrence of tandem damage, due to reductive radical stress involving proteins and lipids, is shown by using a biomimetic model. It is made of unsaturated lipid vesicle suspensions in phosphate buffer in the presence of methionine, either as a single amino acid or as part of a protein such as RNase A, which contains four methionine residues. The radical process starts with the formation of H(.) atoms by reaction of solvated electrons with dihydrogen phosphate anions, which selectively attack the thioether function of methionine. The modification of methionine to alpha-aminobutyric acid is accompanied by the formation of thiyl radicals, which in turn cause the isomerization of the cis fatty acid residues to the trans isomers. The relationship between methionine modification and lipid damage and some details of the reductive radical stress obtained by proteomic analysis of irradiated RNase A are presented.
Ferreri
Carla
C
ISOF, Consiglio Nazionale delle Ricerche, Via P. Gobetti 101, 40129 Bologna, Italy. cferreri@isof.cnr.it
Manco
Immacolata
I
Faraone-Mennella
M Rosaria
MR
Torreggiani
Armida
A
Tamba
Maurizio
M
Manara
Sonia
S
Chatgilialoglu
Chryssostomos
C
D032701:Biomimetics; D005609:Free Radicals / Q000737:chemistry; D006859:Hydrogen / Q000737:chemistry* / Q000378:metabolism; D007536:Isomerism; D008055:Lipids / Q000737:chemistry*; D008715:Methionine / Q000737:chemistry*; D008954:Models, Biological; D010084:Oxidation-Reduction; D012259:Ribonuclease, Pancreatic / Q000737:chemistry* / Q000378:metabolism*; D013059:Spectrum Analysis, Raman
D005609:Free Radicals; D008055:Lipids; D006859:Hydrogen; D008715:Methionine; D012259:Ribonuclease, Pancreatic