Matsumori Nobuaki, Tahara Kazuaki, Yamamoto Hiroko, Morooka Atsushi, Doi Mototsugu, Oishi Tohru, Murata Michio
Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
J Am Chem Soc. 2009 Aug 26;131(33):11855-60. doi: 10.1021/ja9033473.
Although amphotericin B (AmB) is thought to exert its antifungal activity by forming transmembrane ion-permeable self-assemblies together with ergosterol, no previous study has directly proven AmB-ergosterol interaction. To establish the interaction, we measured (2)H NMR using deuterium-labeled sterols and AmB. The (2)H NMR spectra of deuterated ergosterol in palmitoyloleoylphosphatidylcholine (POPC) bilayers showed that fast axial diffusion of erogosterol was almost completely inhibited by the coexistence of AmB. Conversely, cholesterol mobility in POPC membrane was essentially unchanged with or without AmB. These results unequivocally demonstrate that ergosterol has significant interaction with AmB in POPC bilayers. In addition, we examined the mobility of AmB using deuterium-labeled AmB, and found that, although AmB is almost immobilized in sterol-free and cholesterol-containing POPC membranes, a certain ratio of AmB molecules acquires mobility in the presence of ergosterol. The similar mobility of AmB and ergosterol in POPC bilayers confirmed the idea of the direct intermolecular interaction between ergosterol and AmB.
尽管两性霉素B（AmB）被认为是通过与麦角固醇一起形成跨膜离子通透自组装体来发挥其抗真菌活性，但此前尚无研究直接证明AmB与麦角固醇的相互作用。为了确定这种相互作用，我们使用氘标记的固醇和AmB测量了2H NMR。棕榈酰油酰磷脂酰胆碱（POPC）双层中氘代麦角固醇的2H NMR光谱表明，AmB的共存几乎完全抑制了麦角固醇的快速轴向扩散。相反，无论有无AmB，POPC膜中胆固醇的流动性基本不变。这些结果明确表明，在POPC双层中麦角固醇与AmB存在显著相互作用。此外，我们使用氘标记的AmB研究了AmB的流动性，发现尽管AmB在不含固醇和含胆固醇的POPC膜中几乎固定不动，但在存在麦角固醇的情况下，一定比例的AmB分子获得了流动性。POPC双层中AmB和麦角固醇相似的流动性证实了麦角固醇与AmB之间直接分子间相互作用的观点。
