Restoration of respiratory electron-transport reactions in quinone-depleted particle preparations from Anacystis nidulans.
Electron transport from H2, NADPH, NADH and succinate to O2 or ferricytochrome c in respiratory particles isolated from Anacystis nidulans in which hydrogenase had been induced was abolished after extraction of the membranes with n-pentane; oxidation of ascorbate plus NNN'N'-tetramethyl-p-phenylenediamine remained unaffected. Incorporation of authentic ubiquinone-10, plastoquinone-9, menaquinone-7 and phylloquinone (in order of increasing efficiency) restored the electron-transport reactions. ATP-dependent reversed electron flow from NNN'N'-tetramethyl-p-phenylenediamine to NADP+ or, via the membrane-bound hydrogenase, to H+ was likewise abolished by pentane extraction and restored by incorporation of phylloquinone. Participation of the incorporated quinones in the respiratory electron-transport reactions of reconstituted particles was confirmed by measuring the degree of steady-state reduction of the quinones. Isolation and identification of the quinones present in native Anacystis membranes yielded mainly plastoquinone-9 and phylloquinone; neither menaquinone nor alpha-tocopherolquinone could be detected. Together with the results from reconstitution experiments this suggests that phylloquinone might function as the main respiratory quinone in Anacystis nidulans.
D002462:Cell Membrane / Q000378:metabolism; D000458:Cyanobacteria / Q000187:drug effects / Q000378:metabolism*; D003991:Dibromothymoquinone / Q000494:pharmacology; D004579:Electron Transport / Q000187:drug effects; D007700:Kinetics; D009249:NADP / Q000378:metabolism; D009285:Naphthoquinones / Q000494:pharmacology; D010101:Oxygen Consumption / Q000187:drug effects; D011809:Quinones / Q000378:metabolism*; D013772:Tetramethylphenylenediamine / Q000494:pharmacology; D014466:Ultraviolet Rays; D014812:Vitamin K / Q000494:pharmacology
D009285:Naphthoquinones; D011809:Quinones; D014812:Vitamin K; D003991:Dibromothymoquinone; D009249:NADP; D013772:Tetramethylphenylenediamine; C005134:juglone