'Lollipop'-shaped helical structure of a hybrid antimicrobial peptide of temporin B-lipopolysaccharide binding motif and mapping cationic residues in antibacterial activity
'Lollipop'-shaped helical structure of a hybrid antimicrobial peptide of temporin B-lipopolysaccharide binding motif and mapping cationic residues in antibacterial activity
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DOI：
10.1016/j.bbagen.2016.03.025
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发表时间：
2016-06-01
影响因子：
3
通讯作者：
Bhattacharjya, Surajit
中科院分区：
文献类型：
--
作者：
Mohanram, Harini;Bhattacharjya, Surajit
背景：Temporin 是抗生素开发的有吸引力的模板。然而，许多Temporin对革兰氏阴性细菌没有活性。此前，我们证明了脂多糖结合基序肽与temporin的缀合产生了混合非溶血性AMP，可以杀死多种革兰氏阴性细菌。方法：我们对LG21的单个阳离子和极性氨基酸残基进行了系统的丙氨酸置换，LG21是一种由temporin B (TB)和LPS结合基序组成的混合AMP。使用光学光谱方法检查这些含有丙氨酸的 LG21 类似物的抗菌活性、细胞膜透化和脂质体渗漏测定。通过核磁共振波谱法测定了两性离子十二烷基磷酸胆碱 (DPC) 胶束中 LG21 的原子分辨率结构。结果：LG21 的 LPS 结合基序中的阳离子残基对于杀菌和膜透化至关重要。 LG21 的去垢剂结合结构揭示了含有广泛侧链/侧链堆积的螺旋构象，包括 LPS 结合基序中的阳离子/π 相互作用。 LG21 的螺旋结构类似于“棒棒糖”状形状，由紧凑的大芳香族/阳离子头支撑，在 N 端区域具有相对较薄的“棒”。该结构的“头”可能位于胶束-水界面区域，而“粘”区域可能插入胶束的疏水核心。结论：LG21的LPS结合基序在广谱活性中起主导作用，3-D结构为细菌膜的透化提供了合理的机制见解。一般意义：含有LPS结合基序的混合AMP可用于基于结构的广谱抗生素的开发。 (C) 2016 Elsevier B.V. 保留所有权利。
Background: Temporins are attractive templates for the development of antibiotics. However, many temporins are inactive against Gram-negative bacteria. Previously, we demonstrated conjugation of a lipopolysaccharide binding motif peptide to temporins yielded hybrid non-haemolytic AMPs that killed several Gram-negative bacteria.Methods: We carried out a systematic Ala replacement of individual cationic and polar amino acid residues of LG21, a hybrid AMP consisted of temporin B (TB) and LPS binding motif. These Ala containing analogs of LG21 were examined for antibacterial activity, cell membrane permeabilization and liposome leakage assays using optical spectroscopic methods. Atomic resolution structure of LG21 was determined in zwitterionic dodecyl phosphocholine (DPC) micelles by NMR spectroscopy.Results: Cationic residues in the LPS binding motif of LG21 were critical for bactericidal and membrane permeabilization. Detergent bound structure of LG21 revealed helical conformation containing extensive sidechain/sidechain packing including cation/pi interactions in the LPS binding motif. The helical structure of LG21 resembled a 'lollipop' like shape that was sustained by a compacted bulky aromatic/cationic head with a comparatively thinner 'stick' at the N-terminal region. The 'head' of the structure could be localized into micelle-water interfacial region whereas the 'stick' region may be inserted into the hydrophobic core of micelle.Conclusions: The LPS binding motif of LG21 played dominant roles in broad spectrum activity and the 3-D structure provided plausible mechanistic insights for permeabilization of bacterial membrane.General significance: Hybrid AMPs containing LPS binding motif could be useful for the structure based development of broad spectrum antibiotics. (C) 2016 Elsevier B.V. All rights reserved.