Optimization of microbial specificity in cyclic peptides by modulation of hydrophobicity within a defined structural framework
Optimization of microbial specificity in cyclic peptides by modulation of hydrophobicity within a defined structural framework
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DOI：
10.1074/jbc.m107825200
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发表时间：
2002-01-04
影响因子：
4.8
通讯作者：
Hodges, RS
中科院分区：
文献类型：
--
作者：
Kondejewski, LH;Lee, DL;Hodges, RS
在本研究中，我们利用类似物GS14 K4（环状（VKLd-K-Vd-YPL KVKLd-YP，其中d表示D-氨基酸））的结构框架来检查疏水性在微生物活性和特异性中的作用。GS14 K4的疏水性通过分子疏水位点中的残基置换而系统地改变，以产生一系列比母体化合物疏水性更小或更大的类似物。圆二色谱和反相高效液相色谱分析表明，分子的结构相似，只有不同的整体疏水性。发现GS14 K4的疏水性是溶血活性的中点，更多的疏水类似物表现出增加的溶血活性，而更少的疏水类似物表现出降低的溶血活性。对于抗微生物活性，对革兰氏阳性和革兰氏阴性微生物的疏水性要求之间存在差异。GS14 K4的疏水性足以使其对革兰氏阴性微生物和酵母的活性达到最大，随着疏水性的增加，活性没有进一步增加。对于革兰氏阳性微生物，在所测试的六种微生物中的三种中观察到活性随着疏水性的增加而显著增加。治疗指数（计算为肽对微生物相对于人红细胞的特异性的量度）用于定义治疗窗的边界，在该边界内存在每种微生物的最佳肽疏水性。发现革兰氏阴性微生物的治疗窗口处于比革兰氏阳性微生物更低的疏水性水平，尽管后者的限制更可变。我们的研究结果表明，本发明的环肽的活性和特异性之间的平衡可以通过疏水性的系统调节来优化每种微生物。
In the present study we have utilized the structural framework of the analog GS14K4 (cyclo(VKLd-K-Vd-YPL KVKLd-YP, where d denotes a D-amino acid)), to examine the role of hydrophobicity in microbial activity and specificity. The hydrophobicity of GS14K4 was systematically altered by residue replacements in the hydrophobic sites of the molecule to produce a series of analogs that were either less or more hydrophobic than the parent compound. Circular dichroism spectroscopy and reversed-phase high performance liquid chromatography analysis showed that the molecules were structurally similar and only differed in overall hydrophobicity. The hydrophobicity of GS14K4 was found to be the midpoint for hemolytic activity, with more hydrophobic analogs exhibiting increased hemolytic activity and less hydrophobic analogs showing decreased hemolytic activity. For antimicrobial activity there were differences between the hydrophobicity requirements against Gram-positive and Gram-negative microorganisms. The hydrophobicity of GS14K4 was sufficient for maximum activity against Gram-negative microorganisms and yeast, with no further increases in activity occurring with increasing hydrophobicity. With Gram-positive microorganisms significant increases in activity with increasing hydrophobicity were seen in three of the six microorganisms tested. A therapeutic index (calculated as a measure of specificity of the peptides for the microorganisms over human erythrocytes) served to define the boundaries of a therapeutic window within which lay the optimum peptide hydrophobicity for each microorganism. The therapeutic window was found to be at a lower hydrophobicity level for Gram-negative microorganisms than for Gram-positive microorganisms, although the limits were more variable for the latter. Our results show that the balance between activity and specificity in the present cyclic peptides can be optimized for each microorganism by systematic modulation of hydrophobicity.