High-resolution solution structure of a designed peptide bound to lipopolysaccharide: Transferred nuclear overhauser effects, micelle selectivity, and anti-endotoxic activity
High-resolution solution structure of a designed peptide bound to lipopolysaccharide: Transferred nuclear overhauser effects, micelle selectivity, and anti-endotoxic activity
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DOI：
10.1021/bi6025159
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发表时间：
2007-05-22
期刊：
影响因子：
2.9
通讯作者：
David, Sunil A.
中科院分区：
文献类型：
--
作者：
Bhattacharjya, Surajit;Domadia, Prerna N.;David, Sunil A.
设计与脂多糖（LPS）相互作用并获得特定折叠构象的肽可以产生有用的结构见解，以开发抗菌剂。在这项工作中，我们已经构建了一个12个残基的线性肽，YW 12，富含芳香族和脂肪族氨基酸残基与位于中心的伸展的四个连续的带正电荷（KRKR）的残基。在不存在LPS的情况下，YW 12在水溶液中主要是非结构化的。利用转移核Overhauser效应（Tr-NOE）光谱，我们证明了YW 12采用良好的折叠结构作为与LPS的复合物。结构计算表明，YW 12在N-末端呈现延伸构象，随后在其C-末端呈现两个连续的β-转角。疏水核通过大量芳族和非极性残基之间的大量堆积形成，而带正电荷的残基被分离到基本上稳定两亲性结构的单独区域。在使用NF-κ B诱导作为读数的体外LPS中和测定中，YW 12显示中等活性，IC 50值类似于10 μ M。正如预期的那样，色氨酸荧光研究表明，YW 12仅与带负电荷的脂质胶束（包括十二烷基硫酸钠（SDS）、1-棕榈酰-2-油酰磷脂酰-DL-甘油（POPG）和LPS）显示出选择性相互作用，而与两性离子脂质胶束（如十二烷基磷酸胆碱（DPC））未检测到显著的相互作用。远紫外CD研究表明，在带负电荷的胶束中的肽的β-转角或β-折叠样构象的存在下，而没有结构转变是明显的DPC胶束。这些结果表明，YW 12的结构特征可以用来开发无毒的防腐化合物。
Designing peptides that would interact with lipopolysaccharides (LPS) and acquire a specific folded conformation can generate useful structural insights toward the development of anti-sepsis agents. In this work, we have constructed a 12-residue linear peptide, YW12, rich in aromatic and aliphatic amino acid residues with a centrally located stretch of four consecutive positively charged (KRKR) residues. In absence of LPS, YW12 is predominantly unstructured in aqueous solution. Using transferred nuclear Overhauser effect (Tr-NOE) spectroscopy, we demonstrate that YW12 adopts a well-folded structure as a complex with LPS. Structure calculations reveal that YW12 assumes an extended conformation at the N-terminus followed by two consecutive beta-turns at its C-terminus. A hydrophobic core is formed by extensive packing between number of aromatic and nonpolar residues, whereas the positively charged residues are segregated out to a separate region essentially stabilizing an amphipathic structure. In an in vitro LPS neutralization assay using NF-kappa B induction as the readout, YW12 shows moderate activity with an IC50 value of similar to 10 mu M. As would be expected, tryptophan fluorescence studies demonstrate that YW12 shows selective interactions only with the negatively charged lipid micelles including sodium dodecyl sulfate (SDS), 1-palmitoyl-2-oleoylphosphatidyl-DL-glycerol (POPG), and LPS, and no significant interactions are detected with zwitterionic lipid micelles such as dodecyl-phosphocholine (DPC). Far-UV CD studies indicate the presence of beta-turns or beta-sheet-like conformations of the peptide in negatively charged micelles, whereas no structural transitions are apparent in DPC micelles. These results suggest that structural features of YW12 could be utilized to develop nontoxic antisepsis compounds.