Konno H, Matsuya H, Okamoto M, Sato T, Tanaka Y, Yokoyama K, Kataoka T, Nagai K, Wasserman H H, Ohkuma S
Laboratory of Biochemistry, Department of Molecular and Cell Biology, Faculty of Pharmaceutical Sciences, Kanazawa University, Kanazawa, Ishikawa, 920-0934, Japan.
J Biochem. 1998 Sep;124(3):547-56. doi: 10.1093/oxfordjournals.jbchem.a022147.
Prodigiosin, metacycloprodigiosin, and prodigiosin 25-C all inhibited the acidification activity of submitochondrial and bacterial (Escherichia coli) F-ATPases (FoF1-ATPases) strongly (IC50 = 20-30 and 24-30 pmol/mg protein, respectively), without affecting significantly the ATP hydrolysis activity. Their effect on the acidification activity was rapid and reversible, showing non-competitive apparent Ki values of the order of nM to sub-nM. However, unlike FCCP (an ordinary uncoupler of oxidative phosphorylation), they showed no protonophoric activity, as demonstrated by the absence of acceleration of ATP hydrolysis. Prodigiosins also inhibited the acidification of proteoliposomes reconstituted from phospholipids and purified F-ATPase of E. coli, suggesting that their acidification-inhibitory effect is not due to the inhibition of anion channels. They did not, however, inhibit the ATP-dependent formation of membrane potential of F-ATPase vesicles. Furthermore, they inhibited and quickly reversed acidification by F-ATPase only in the presence of chloride, and not in the presence of gluconate anion. Finally, they induced swelling of liposomes and submitochondrial particles in isotonic solution of ammonium chloride but not ammonium gluconate, suggesting that intravesicular entry of Cl- is promoted by prodigiosins. These results suggest that prodigiosins uncouple F-ATPases through promotion of H+/Cl- symport (or OH-/Cl- exchange) across vesicular membranes.
灵菌红素、间型灵菌红素和灵菌红素25-C均能强烈抑制亚线粒体和细菌（大肠杆菌）F-ATP酶（F₀F₁-ATP酶）的酸化活性（IC₅₀分别为20 - 30和24 - 30 pmol/mg蛋白），且对ATP水解活性无显著影响。它们对酸化活性的作用迅速且可逆，表观Ki值呈非竞争性，在纳摩尔至亚纳摩尔范围内。然而，与FCCP（一种普通的氧化磷酸化解偶联剂）不同，它们没有质子载体活性，这可通过ATP水解未加速得以证明。灵菌红素还能抑制由磷脂和纯化的大肠杆菌F-ATP酶重构的蛋白脂质体的酸化，这表明它们的酸化抑制作用并非由于阴离子通道的抑制。然而，它们并不抑制F-ATP酶囊泡的ATP依赖性膜电位形成。此外，它们仅在存在氯离子的情况下抑制并迅速逆转F-ATP酶引起的酸化，而在存在葡萄糖酸根阴离子时则无此作用。最后，它们在氯化铵等渗溶液中而非葡萄糖酸铵中诱导脂质体和亚线粒体颗粒肿胀，这表明灵菌红素促进了氯离子进入囊泡内部。这些结果表明，灵菌红素通过促进跨囊泡膜的H⁺/Cl⁻同向转运（或OH⁻/Cl⁻交换）使F-ATP酶解偶联。
