Krishnamoorthy Rajavenkatesh, Adhikari Priyanka, Anaikutti Parthiban
Organic and Bioorganic Chemistry Laboratory, CSIR-CLRI Adyar Chennai-600020 Tamil Nadu India.
Department of Chemistry, Sethu Institute of Technology Kariapatti Virudunagar-626115 Tamil Nadu India
RSC Adv. 2023 May 23;13(23):15594-15605. doi: 10.1039/d3ra02473c. eCollection 2023 May 22.
We designed and synthesised the N-terminally labeled cationic and hydrophobic peptides, , FFKKSKEKIGKEFKKIVQKI (P1) and FRRSRERIGREFRRIVQRI (P2) related to the human cathelicidin LL-37 peptide. The integrity and molecular weight of the peptides were confirmed by mass spectrometry. The purity and homogeneity of peptides P1 and P2 were determined by comparing LCMS or analytical HPLC chromatograms. The circular dichroism spectroscopy reveals the conformational transitions upon interaction with membranes. Predictably, peptides P1 and P2 showed a random coil structure in the buffer and formed α-helix secondary structure in TFE and SDS micelles. This assessment was further confirmed by 2D NMR spectroscopic methods. The analytical HPLC binding assay measurements revealed that peptides P1 and P2 display preferential interactions with the anionic lipid bilayer (POPC:POPG) moderately than zwitterionic (POPC). The efficacies of the peptides were tested against Gram-positive and Gram-negative bacteria. It is imperative to note here that the arginine-rich P2 exerted higher activity against all the test organisms as compared with that shown by the lysine-rich peptide P1. To test the toxicity of these peptides, a hemolytic assay was performed. P1 and P2 showed very little to no toxicity for a hemolytic assay, which is significant for P1 and P2 to be used as potential therapeutic agents in practical applications. Both peptides P1 and P2 were non-hemolytic and appeared to be more promising as they demonstrated wide-spectrum antimicrobial activity.
我们设计并合成了与人类cathelicidin LL-37肽相关的N端标记的阳离子和疏水肽，即FFKKSKEKIGKEFKKIVQKI（P1）和FRRSRERIGREFRRIVQRI（P2）。通过质谱确认了肽的完整性和分子量。通过比较LCMS或分析型HPLC色谱图来测定肽P1和P2的纯度和均一性。圆二色光谱揭示了与膜相互作用时的构象转变。可以预见，肽P1和P2在缓冲液中呈无规卷曲结构，在TFE和SDS胶束中形成α-螺旋二级结构。二维NMR光谱方法进一步证实了这一评估。分析型HPLC结合测定结果表明，肽P1和P2与阴离子脂质双层（POPC:POPG）的优先相互作用比两性离子脂质双层（POPC）更强。测试了这些肽对革兰氏阳性菌和革兰氏阴性菌的功效。必须在此指出的是，与富含赖氨酸的肽P1相比，富含精氨酸的P2对所有测试生物体均表现出更高的活性。为了测试这些肽的毒性，进行了溶血试验。P1和P2在溶血试验中显示出极低的毒性或无毒性，这对于P1和P2在实际应用中作为潜在治疗剂具有重要意义。肽P1和P2均无溶血作用，并且由于它们表现出广谱抗菌活性，因此似乎更具前景。
