Veerman Enno C I, Valentijn-Benz Marianne, Nazmi Kamran, Ruissen Anita L A, Walgreen-Weterings Els, van Marle Jan, Doust Alexander B, van't Hof Wim, Bolscher Jan G M, Amerongen Arie V Nieuw
Department of Oral Biochemistry, Academic Centre for Dentistry Amsterdam, Vrije Universiteit and Universiteit van Amsterdam, 1081 BT Amsterdam, The Netherlands.
J Biol Chem. 2007 Jun 29;282(26):18831-41. doi: 10.1074/jbc.M610555200. Epub 2007 May 7.
Inhibitors of the energy metabolism, such as sodium azide and valinomycin, render yeast cells completely resistant against the killing action of a number of cationic antimicrobial peptides, including the salivary antimicrobial peptide Histatin 5. In this study the Histatin 5-mediated killing of the opportunistic yeast Candida albicans was used as a model system to comprehensively investigate the molecular basis underlying this phenomenon. Using confocal and electron microscopy it was demonstrated that the energy poison azide reversibly blocked the entry of Histatin 5 at the level of the yeast cell wall. Azide treatment hardly induced depolarization of the yeast cell membrane potential, excluding it as a cause of the lowered sensitivity. In contrast, the diminished sensitivity to Histatin 5 of energy-depleted C. albicans was restored by increasing the fluidity of the membrane using the membrane fluidizer benzyl alcohol. Furthermore, rigidification of the membrane by incubation at low temperature or in the presence of the membrane rigidifier Me(2)SO increased the resistance against Histatin 5, while not affecting the energy charge of the cell. In line, azide induced alterations in the physical state of the interior of the lipid bilayer. These data demonstrate that changes in the physical state of the membrane underlie the increased resistance to antimicrobial peptides.
能量代谢抑制剂，如叠氮化钠和缬氨霉素，可使酵母细胞对多种阳离子抗菌肽（包括唾液抗菌肽组蛋白5）的杀伤作用产生完全抗性。在本研究中，以组蛋白5介导的对机会性酵母白色念珠菌的杀伤作用作为模型系统，全面研究这一现象背后的分子基础。利用共聚焦显微镜和电子显微镜证明，能量毒物叠氮化钠在酵母细胞壁水平可逆地阻断组蛋白5的进入。叠氮化钠处理几乎不会诱导酵母细胞膜电位去极化，排除其作为敏感性降低原因的可能性。相反，通过使用膜流化剂苯甲醇增加膜的流动性，可恢复能量耗尽的白色念珠菌对组蛋白5降低的敏感性。此外，在低温下孵育或在膜硬化剂二甲基亚砜存在下使膜硬化，可增加对组蛋白5的抗性，同时不影响细胞的能量状态。同样，叠氮化钠诱导脂质双层内部物理状态的改变。这些数据表明，膜物理状态的变化是对抗菌肽抗性增加的基础。
