Abstract
Antimycin A causes a biphasic suppression of the light-induced membrane potential generation in Rhodospirillum rubrum and Rhodopseudomonas sphaeroides chromatophores incubated anaerobically. The first phase is observed at low antibiotic concentrations and is apparently due to its action as a cyclic electron transfer inhibitor. The second phase is manifested at concentrations which are greater than 1–2 μM and is due to uncoupling that may be connected with an antibiotic-induced dissipation of the electrochemical H + gradient across the chromatophore membrane. The inhibitory effect of anti-mycin added at low concentrations under aerobic conditions is removed by succinate to a large extent. It is expected that the electrogenic cyclic redox chain in the bacterial chromatophores incubated under conditions of continuous illumination may function at two regimes: (1) as a complete chain involving all the redox components, and (2) as a shortened chain involving only the P-870 photoreaction center, ubiquinone and cytochrome c 2.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have