title: Alkyl-substituted phenylamino derivatives of 7-nitrobenz-2-oxa-1,3-diazole as uncouplers of oxidative phosphorylation and antibacterial agents: involvement of membrane proteins in the uncoupling action.
abstract: In search for new effective uncouplers of oxidative phosphorylation, we studied 4-aryl amino derivatives of a fluorescent group 7-nitrobenz-2-oxa-1,3-diazol (NBD). In our recent work (Denisov et al., Bioelectrochemistry, 2014), NBD-conjugated alkyl amines (NBD-Cn) were shown to exhibit uncoupling activity. It was concluded that despite a pKavalue being about 10, the expected hindering of the uncoupling activity could be overcome by insertion of an alkyl chain. There is evidence in the literature that the introduction of an aryl substituent in the 4-amino NBD group shifts the pKato neutral values. Here we report the data on the properties of a number of 4-arylamino derivatives of NBD, namely, alkylphenyl-amino-NBD (Cn-phenyl-NBD) with varying alkyl chain Cn. By measuring the electrical current across planar bilayer lipid membrane, the protonophoric activity of Cn-phenyl-NBD at neutral pH grew monotonously from C1- to C6-phenyl-NBD. All of these compounds increased the respiration rate and reduced the membrane potential of isolated rat liver mitochondria. Importantly, the uncoupling action of C6- and C4-phenyl-NBD was partially reversed by glutamate, diethyl pyrocarbonate (DEPC), 6-ketocholestanol, and carboxyatractyloside, thus pointing to the involvement of membrane proteins in the uncoupling activity of Cn-phenyl-NBD in mitochondria. The pronounced recoupling effect of DEPC, an inhibitor of an aspartate-glutamate carrier (AGC), and that of its substrates for the first time highlighted AGC participation in the action of potent uncouplers on mitochondria. C6-phenyl-NBD produced strong antimicrobial effect on Bacillus subtilis, which manifested itself in cell membrane depolarization and suppression of bacterial growth at submicromolar concentrations.
authors.affiliation: Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory 1, Moscow 119991, Russia. Electronic address: antonen@genebee.msu.ru.
authors.forename: Yuri N
authors.initials: YN
authors.lastname: Antonenko
authors.affiliation: Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory 1, Moscow 119991, Russia; Faculty of Chemistry, Lomonosov Moscow State University, Leninskie Gory 1, Moscow 119991, Russia.
authors.forename: Stepan S
authors.initials: SS
authors.lastname: Denisov
authors.affiliation: Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory 1, Moscow 119991, Russia.
authors.forename: Ljudmila S
authors.initials: LS
authors.lastname: Khailova
authors.affiliation: Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory 1, Moscow 119991, Russia.
authors.forename: Pavel A
authors.initials: PA
authors.lastname: Nazarov
authors.affiliation: Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory 1, Moscow 119991, Russia.
authors.forename: Tatyana
authors.initials: T
authors.lastname: Rokitskaya
authors.affiliation: Faculty of Chemistry, Lomonosov Moscow State University, Leninskie Gory 1, Moscow 119991, Russia.
authors.forename: Vadim N
authors.initials: VN
authors.lastname: Tashlitsky
authors.affiliation: Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory 1, Moscow 119991, Russia.
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Firsov
authors.affiliation: Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory 1, Moscow 119991, Russia.
authors.forename: Galina A
authors.initials: GA
authors.lastname: Korshunova
authors.affiliation: Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory 1, Moscow 119991, Russia. Electronic address: kotova@genebee.msu.ru.
authors.forename: Elena A
authors.initials: EA
authors.lastname: Kotova
mesh_terms: D026922:Amino Acid Transport Systems, Acidic / Q000737:chemistry / Q000378:metabolism; D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D017920:Antiporters / Q000737:chemistry / Q000378:metabolism; D001412:Bacillus subtilis / Q000187:drug effects; D004047:Diethyl Pyrocarbonate / Q000737:chemistry / Q000378:metabolism; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism; D008564:Membrane Potentials / Q000187:drug effects; D008565:Membrane Proteins / Q000737:chemistry* / Q000378:metabolism; D008930:Mitochondria, Liver / Q000187:drug effects / Q000378:metabolism; D010069:Oxadiazoles / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D010085:Oxidative Phosphorylation / Q000187:drug effects*; D051381:Rats
chemical_list: C526864:7-nitrobenz-2-oxa-1,3-diazole; D026922:Amino Acid Transport Systems, Acidic; D000900:Anti-Bacterial Agents; D017920:Antiporters; D008051:Lipid Bilayers; D008565:Membrane Proteins; D010069:Oxadiazoles; C051046:aspartate-glutamate carrier; D004047:Diethyl Pyrocarbonate
keywords: Bilayer lipid membrane; Membrane potential; Mitochondria; NBD; Oxidative phosphorylation; Protonophore; Uncoupler