Peptide-Lipid Huge Toroidal Pore, a New Antimicrobial Mechanism Mediated by a Lactococcal Bacteriocin, Lacticin Q
Peptide-Lipid Huge Toroidal Pore, a New Antimicrobial Mechanism Mediated by a Lactococcal Bacteriocin, Lacticin Q
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DOI：
10.1128/aac.00209-09
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发表时间：
2009-05
影响因子：
4.9
通讯作者：
F. Yoneyama;Y. Imura;K. Ohno;T. Zendo;J. Nakayama;K. Matsuzaki;K. Sonomoto
中科院分区：
文献类型：
--
作者：
F. Yoneyama;Y. Imura;K. Ohno;T. Zendo;J. Nakayama;K. Matsuzaki;K. Sonomoto
摘要 Lacticin Q 是由乳酸乳球菌 QU 5 产生的一种成孔细菌素，其抗菌活性在纳摩尔范围内。 Lactin Q 诱导钙黄绿素从带负电荷的脂质体中泄漏。然而，通过光散射没有观察到脂质体的形态变化。与钙黄绿素渗漏相伴，乳酸菌素 Q 在最初与膜结合后 2 秒内就从脂质体的外叶转移到内叶。 Lactin Q 也会诱导脂质翻转。这些结果表明，乳酸菌Q的抗菌机制可以用环形孔模型来描述。这是首次报道革兰氏阳性菌的细菌素形成环形孔。乳酸菌 Q 从脂质体中泄漏出直径为 4.6 nm 的荧光标记葡聚糖。此外，乳酸菌 Q 还会导致活细菌细胞中小蛋白质的泄漏，例如绿色荧光蛋白。目前还没有其他关于具有蛋白质渗漏特性的抗菌肽的报道。所提出的乳酸菌Q的孔形成模型如下：（i）与外膜小叶快速结合； (ii) 形成至少 4.6 nm 的孔，导致蛋白质泄漏和脂质翻转； (iii) 乳酸素 Q 分子从外膜小叶迁移至内膜小叶。因此，我们将乳酸菌 Q 抗菌机制中的新型孔模型称为“巨大环形孔”。
ABSTRACT Lacticin Q is a pore-forming bacteriocin produced by Lactococcus lactis QU 5, and its antimicrobial activity is in the nanomolar range. Lacticin Q induced calcein leakage from negatively charged liposomes. However, no morphological changes in the liposomes were observed by light scattering. Concomitantly with the calcein leakage, lacticin Q was found to translocate from the outer to the inner leaflet of the liposomes, after it initially bound to the membrane within 2 s. Lacticin Q also induced lipid flip-flop. These results reveal that the antimicrobial mechanism of lacticin Q can be described by the toroidal pore model. This is the first report of a bacteriocin of gram-positive bacteria that forms a toroidal pore. From liposomes, lacticin Q leaked fluorescence-labeled dextran with a diameter of 4.6 nm. In addition, lacticin Q caused the leakage of small proteins, such as the green fluorescent protein, from live bacterial cells. There are no other reports of antimicrobial peptides that exhibit protein leakage properties. The proposed pore formation model of lacticin Q is as follows: (i) quick binding to outer membrane leaflets; (ii) the formation of at least 4.6-nm pores, causing protein leakage with lipid flip-flop; and (iii) the migration of lacticin Q molecules from the outer to the inner membrane leaflets. Consequently, we termed the novel pore model in the antimicrobial mechanism of lacticin Q a “huge toroidal pore.”