title: Ligand-selective modulation of the permeability transition pore by arginine modification. Opposing effects of p-hydroxyphenylglyoxal and phenylglyoxal.
abstract: Chemical modification of mitochondria with the arginine-specific reagents phenylglyoxal (PGO) and 2,3-butanedione (BAD) decreases the Ca(2+) sensitivity of the permeability transition pore (PTP) and stabilizes it in the closed conformation (Eriksson, O., Fontaine, E., and Bernardi, P. (1998) J. Biol. Chem. 273, 12669-12674). Unexpectedly, modification of mitochondria with the arginine-specific reagent p-hydroxyphenylglyoxal (OH-PGO) resulted instead in PTP opening. Sequential modification with OH-PGO and PGO (or BAD) revealed that the effects on the PTP depended on the order of the additions. PTP opening was observed when OH-PGO preceded, and PTP closing was observed when OH-PGO followed, the addition of PGO (or BAD). The differential effects of OH-PGO and PGO on the PTP open probability (i) were not modified by the conformation-specific ligands of the adenine nucleotide translocase bongkrekate and atractylate; and (ii) were also observed in de-energized mitochondria, indicating that the effect is exerted directly on the PTP. OH-PGO dramatically sensitized PTP opening, which was triggered by depolarization even in the presence of EGTA. These data show that arginine modification modulates the PTP conformation in a ligand-selective fashion and suggest that the effects of OH-PGO, PGO, and BAD are mediated by the same arginine residues. We analyzed the structure of the arginine adducts by matrix-assisted laser desorption ionization and time-of-flight mass spectrometry using a test peptide and N-acetylarginine. The results indicate that both OH-PGO and PGO react with arginine at a stoichiometry of 2:1 and form stable adducts that may be feasible to identify the PTP at the molecular level.
authors.affiliation: Helsinki Biophysics and Biomembrane Group, Institute of Biomedicine, University of Helsinki, FIN-00014, Helsinki, Finland.
authors.forename: Matts D
authors.initials: MD
authors.lastname: Linder
authors.forename: Sarune
authors.initials: S
authors.lastname: Morkunaite-Haimi
authors.forename: Paavo K J
authors.initials: PK
authors.lastname: Kinnunen
authors.forename: Paolo
authors.initials: P
authors.lastname: Bernardi
authors.forename: Ove
authors.initials: O
authors.lastname: Eriksson
mesh_terms: D000818:Animals; D001120:Arginine / Q000737:chemistry* / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology; D007473:Ion Channels; D008024:Ligands; D008099:Liver / Q000737:chemistry / Q000378:metabolism; D008297:Male; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D008928:Mitochondria / Q000737:chemistry / Q000187:drug effects* / Q000378:metabolism; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D015394:Molecular Structure; D010658:Phenylglyoxal / Q000737:chemistry / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D004791:Enzyme Inhibitors; D007473:Ion Channels; D008024:Ligands; D008565:Membrane Proteins; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D001120:Arginine; D010658:Phenylglyoxal; D002118:Calcium