Surface charge on thylakoid membranes: regulation of photosynthetic electron transfer in cyanobacteria

✍ Scribed by Eugene L. Barsky; Michael V. Gusev; Nelly V. Kazennova; Vitaly D. Samuilov

• Publisher: Springer
• Year: 1984
• Tongue: English
• Weight: 479 KB
• Volume: 138
• Category: Article
• ISSN: 0302-8933
• DOI: 10.1007/bf00425407

✦ Synopsis

The establishment of the steady-state rate of photosynthetic O2 evolution by cells of Anabaena variabilis and other cyanobacteria was found to be preceded by a lag-phase the duration of which depended on the time of cell preincubation in the dark. Electron acceptors (benzoquinone, N,N,N',N'-tetramethyl-p-phenylenediamine, 2,3,5,6-tetramethyl-p-phenylenediamine or 2,6-dichlorophenolindophenol) abolished the lag-phase as well as the inhibitory effect of cyanide on electron transfer. Mono-, diand trivalent cations added to the cell suspension markedly reduced the lag-phase. As cation concentrations were increased, acceleration and subsequent deceleration of the O2 evolution rate were observed. The efficient concentrations of cations decreased as their valency increased. The lag-phase and the rate of photosynthetic O2 evolution by the blue-green algae are suggested to depend on the value of the membrane surface charge governing the electrostatic interaction between unidentified membrane-bound redox components. The combination of valinomycin and nigericin as well as gramicidin D enhanced the duration of the lagphase by deenergization of thylakoid membrane.