Antimicrobial and Membrane Disrupting Activities of a Peptide Derived from the Human Cathelicidin Antimicrobial Peptide LL37
Antimicrobial and Membrane Disrupting Activities of a Peptide Derived from the Human Cathelicidin Antimicrobial Peptide LL37
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DOI：
10.1016/j.bpj.2009.09.060
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发表时间：
2010-01-20
影响因子：
3.4
通讯作者：
Ramamoorthy, Ayyalusamy
中科院分区：
文献类型：
--
作者：
Thennarasu, Sathiah;Tan, Anmin;Ramamoorthy, Ayyalusamy
一个21个残基的多肽片段LL7-27(RKSKEKIGKEFKRIVQRIKDF)，对应于唯一的人类肠道抗菌素抗菌肽LL37的7-27残基，被证明对微生物(特别是革兰氏阳性菌)有很强的活性，但对红细胞没有活性。通过差示扫描量热法、荧光、圆二色谱和核磁共振实验对LL7-27的结构、膜取向和靶膜选择性进行了表征。苯胺-8-磺酸摄取试验表明，LL37和LL7-27诱导的大肠杆菌外膜扰动有两种不同的模式。圆二色谱结果表明，与LL37不同，在LL7-27中，构象转变是由脂质特异性相互作用介导的。当它与阴离子(但不是两性离子)小泡结合时，它折叠成a螺旋构象，并且也不会导致染料从两性离子脂质小泡中渗出。差示扫描量热分析表明，LL7-27与DMPC/DMPG(3：1)脂质体完全结合，但在DMPC脂质体中出现富肽和贫肽结构域。对机械排列的脂质双层的N-15核磁共振实验表明，像全长肽LL37一样，肽LL7-27定位在靠近双层表面的位置，表明该肽的作用机制是地毯式的。从含有LL7-27的POPC/POPG(3：1)双层膜获得的P-31核磁共振谱显示，脂双层结构被严重破坏，这与多肽诱导POPC/POPG(3：1)囊泡渗出染料的能力一致。胆固醇被证明可以抑制多肽诱导的脂质双层结构的紊乱。这些结果解释了细菌对LL7-27的敏感性和红细胞对LL7-27的耐药性，并可能对膜选择治疗药物的设计有一定的指导意义。
A 21-residue peptide segment, LL7-27 (RKSKEKIGKEFKRIVQRIKDF), corresponding to residues 7-27 of the only human cathelicidin antimicrobial peptide, LL37, is shown to exhibit potent activity against microbes (particularly Gram-positive bacteria) but not against erythrocytes. The structure, membrane orientation, and target membrane selectivity of LL7-27 are characterized by differential scanning calorimetry, fluorescence, circular dichroism, and NMR experiments. An anilinonaphthalene-8-sulfonic acid uptake assay reveals two distinct modes of Escherichia coli outer membrane perturbation elicited by LL37 and LL7-27. The circular dichroism results show that conformational transitions are mediated by lipid-specific interactions in the case of LL7-27, unlike LL37. It folds into an a-helical conformation upon binding to anionic (but not zwitterionic) vesicles, and also does not induce dye leakage from zwitterionic lipid vesicles. Differential scanning calorimetry thermograms show that LL7-27 is completely integrated with DMPC/DMPG (3:1) liposomes, but induces peptide-rich and peptide-poor domains in DMPC liposomes. N-15 NMR experiments on mechanically aligned lipid bilayers suggest that, like the full-length peptide LL37, the peptide LL7-27 is oriented close to the bilayer surface, indicating a carpet-type mechanism of action for the peptide. P-31 NMR spectra obtained from POPC/POPG (3:1) bilayers containing LL7-27 show substantial disruption of the lipid bilayer structure and agree with the peptide's ability to induce dye leakage from POPC/POPG (3:1) vesicles. Cholesterol is shown to suppress peptide-induced disorder in the lipid bilayer structure. These results explain the susceptibility of bacteria and the resistance of erythrocytes to LL7-27, and may have implications for the design of membrane-selective therapeutic agents.