Multiple Peptide Resistance Factor (MprF)-mediated Resistance of Staphylococcus aureus against Antimicrobial Peptides Coincides with a Modulated Peptide Interaction with Artificial Membranes Comprising Lysyl-Phosphatidylglycerol
Multiple Peptide Resistance Factor (MprF)-mediated Resistance of Staphylococcus aureus against Antimicrobial Peptides Coincides with a Modulated Peptide Interaction with Artificial Membranes Comprising Lysyl-Phosphatidylglycerol
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DOI：
10.1074/jbc.m111.226886
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发表时间：
2011-05-27
影响因子：
4.8
通讯作者：
Gutsmann, Thomas
中科院分区：
文献类型：
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作者：
Andrae, Joerg;Goldmann, Torsten;Gutsmann, Thomas
对金黄色葡萄球菌的膜脂磷脂酰甘油（PG）进行修饰，通过酶转移l-赖氨酸残基导致赖氨酸-PG将PG的净电荷从-1转化为+1，并被认为赋予对阳离子抗菌肽（amp）的抗性。赖氨酸- pg的合成和转运到细菌膜的外小叶是由膜蛋白MprF完成的。因此，缺乏功能性mprF基因的突变体特别容易受到amp的作用。因此，我们的目的是阐明赖氨酸- pg是否以及在多大程度上调节各种amp的膜结合、插入和渗透。将Lysyl-PG掺入模拟金黄色葡萄球菌细胞质膜的人工脂质双层中。此外，我们测定了肽对金黄色葡萄球菌SA113临床分离株和两个缺乏功能性mprF基因突变体的活性，并通过透射电镜观察了肽诱导的细菌超微结构变化。研究的肽是：(i) NK-2，哺乳动物nk -裂解素的α -螺旋片段，（ii） arenicin-1，蛔虫α -片肽，和（iii）蜂毒蜂毒素。通过FRET光谱、傅里叶变换红外光谱和平面脂质双分子层的电测量获得的生物物理数据与肽的生物活性相关。他们强烈支持肽膜相互作用是根除金黄色葡萄球菌的先决条件的假设。然而，膜的性质，如流动性，电容和电导率的调制程度和模式是独特的每一个肽。总之，我们的数据支持并强调了赖氨酸- pg对金黄色葡萄球菌对抗菌肽耐药的重要性。
Modification of the membrane lipid phosphatidylglycerol (PG) of Staphylococcus aureus by enzymatic transfer of a L-lysine residue leading to lysyl-PG converts the net charge of PG from -1 to +1 and is thought to confer resistance to cationic antimicrobial peptides (AMPs). Lysyl-PG synthesis and translocation to the outer leaflet of the bacterial membrane are achieved by the membrane protein MprF. Consequently, mutants lacking a functional mprF gene are in particular vulnerable to the action of AMPs. Hence, we aim at elucidating whether and to which extent lysyl-PG modulates membrane binding, insertion, and permeabilization by various AMPs. Lysyl-PG was incorporated into artificial lipid bilayers, mimicking the cytoplasmic membrane of S. aureus. Moreover, we determined the activity of the peptides against a clinical isolate of S. aureus strain SA113 and two mutants lacking a functional mprF gene and visualized peptide-induced ultrastructural changes of bacteria by transmission electron microscopy. The studied peptides were: (i) NK-2, an alpha-helical fragment of mammalian NK-lysin, (ii) arenicin-1, a lugworm alpha-sheet peptide, and (iii) bee venom melittin. Biophysical data obtained by FRET spectroscopy, Fourier transform infrared spectroscopy, and electrical measurements with planar lipid bilayers were correlated with the biological activities of the peptides. They strongly support the hypothesis that peptide-membrane interactions are a prerequisite for eradication of S. aureus. However, degree and mode of modulation of membrane properties such as fluidity, capacitance, and conductivity were unique for each of the peptides. Altogether, our data support and underline the significance of lysyl-PG for S. aureus resistance to AMPs.