Nasompag Sawinee, Siritongsuk Pawinee, Thammawithan Saengrawee, Srichaiyapol Oranee, Prangkio Panchika, Camesano Terri A, Sinthuvanich Chomdao, Patramanon Rina
Interdisciplinary Graduate Program in Genetic Engineering, The Graduate School, Kasetsart University, Bangkok 10900, Thailand.
Department of Biochemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand.
Membranes (Basel). 2021 Jun 30;11(7):495. doi: 10.3390/membranes11070495.
Lipopeptides have been extensively studied as potential antimicrobial agents. In this study, we focused on the C-KYR lipopeptide, a modified version of the KYR tripeptide with myristic acid at the N-terminus. Here, membrane perturbation of live treated with the parent KYR and C-KYR peptides was compared at the nanoscale level using AFM imaging. AFM analyses, including average cellular roughness and force spectroscopy, revealed the severe surface disruption mechanism of C-KYR. A loss of surface roughness and changes in topographic features included membrane shrinkage, periplasmic membrane separation from the cell wall, and cytosolic leakage. Additional evidence from synchrotron radiation FTIR microspectroscopy (SR-FTIR) revealed a marked structural change in the membrane component after lipopeptide attack. The average roughness of the cell before and after treatment with C-KYR was 129.2 ± 51.4 and 223.5 ± 14.1 nm, respectively. The average rupture force of the cell treated with C-KYR was 0.16 nN, four times higher than that of the untreated cell. Our study demonstrates that the mechanistic effect of the lipopeptide against bacterial cells can be quantified through surface imaging and adhesion force using AFM.
脂肽作为潜在的抗菌剂已被广泛研究。在本研究中，我们聚焦于C-KYR脂肽，它是KYR三肽的修饰版本，在N端带有肉豆蔻酸。在此，使用原子力显微镜（AFM）成像在纳米尺度上比较了用亲本KYR和C-KYR肽处理的活细胞的膜扰动情况。AFM分析，包括平均细胞粗糙度和力谱分析，揭示了C-KYR严重的表面破坏机制。表面粗糙度的丧失和形貌特征的变化包括膜收缩、周质膜与细胞壁分离以及胞质泄漏。同步辐射傅里叶变换红外光谱（SR-FTIR）的其他证据显示，脂肽攻击后膜成分发生了显著的结构变化。用C-KYR处理前后细胞的平均粗糙度分别为129.
