Dissociation of antimicrobial and hemolytic activities in cyclic peptide diastereomers by systematic alterations in amphipathicity
Dissociation of antimicrobial and hemolytic activities in cyclic peptide diastereomers by systematic alterations in amphipathicity
复制标题
DOI：
10.1074/jbc.274.19.13181
复制
发表时间：
1999-05-07
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;Jelokhani-Niaraki, M;Hodges, RS
我们研究了一系列头到尾的同源环状抗菌肽中的两亲性在描述导致高抗菌活性与低溶血活性(Le.较高的治疗指数)。GS14，Cyclo(VKLKVd-YPLKVKLd-YP)是在葛兰素S(GS)的基础上设计的，以高度两亲性的β-折叠构象存在，并作为本研究的基础化合物。合成了14个GS14的非对映异构体；每个非对映异构体在GS14的框架内都含有不同的单一对映体取代基。CD和核磁共振谱表明，所有非对映异构体的β-折叠结构在水溶液中都被破坏了；然而，所有非对映异构体在疏水环境中都表现出不同的结构诱导性。由于非对映异构体具有相同的组成、序列和固有的疏水性，因此可以根据反相高效液相色谱的保留时间对非对映异构体的两亲性进行分级，两者之间存在明显的相关性，表明高两亲性导致非对映异构体具有高的溶血活性和低的抗菌活性，后者可能是高度两亲性的多肽对革兰氏阴性微生物外膜成分亲和力增强的结果。具有最有利的治疗指数的非对映异构体具有一些最低的两亲性，尽管存在一个阈值，低于该阈值的抗菌活性会降低。最好的非对映异构体表现出比GS14低130倍的溶血活性，并极大地提高了抗菌活性，导致许多微生物的治疗指数提高了1000至10,000倍。该多肽对革兰氏阴性菌的治疗指数是GS的16-32倍，特异性显著提高。我们的研究结果表明，在限制性环状抗菌肽的设计中，高度的两亲性是不可取的，最佳的两亲性可以通过系统的对映体取代来定义。
We have investigated the role of amphipathicity in a homologous series of head-to-tail cyclic antimicrobial peptides in efforts to delineate features resulting in high antimicrobial activity coupled with low hemolytic activity (Le. a high therapeutic index). The peptide GS14, cyclo(VKLKVd-YPLKVKLd-YP), designed on the basis of gramicidin S (GS), exists in a preformed highly amphipathic beta-sheet conformation and was used as the base compound for this study. Fourteen diastereomers of GS14 were synthesized; each contained a different single enantiomeric substitution within the framework of GS14, The beta-sheet structure of all GS14 diastereomers was disrupted as determined by CD and NMR spectroscopy under aqueous conditions; however, all diastereomers exhibited differential structure inducibility in hydrophobic environments. Because the diastereomers all have the same composition, sequence, and intrinsic hydrophobicity, the amphipathicity of the diastereomers could be ranked based upon retention time from reversed-phase high performance liquid chromatography, There was a clear correlation showing that high amphipathicity resulted in high hemolytic activity and low antimicrobial activity in the diastereomers, The latter may be the result of increased affinity of highly amphipathic peptides to outer membrane components of Gram-negative microorganisms. The diastereomers possessing the most favorable therapeutic indices possessed some of the lowest amphipathicities, although there was a threshold value below which antimicrobial activity decreased. The best diastereomer exhibited 130-fold less hemolytic activity compared with GS14, as well as greatly increased antimicrobial activities, resulting in improvement in therapeutic indices of between 1,000- and 10,000 fold for a number of microorganisms. The therapeutic indices of this peptide were between 16- and 32-fold greater than GS for Gram-negative microorganisms and represents a significant improvement in specificity over GS, Our findings show that a highly amphipathic nature is not desirable in the design of constrained cyclic antimicrobial peptides and that an optimum amphipathicity can be defined by systematic enantiomeric substitutions.