Faculty of Physics, Laboratory of Biophysics and Medical Physics, Alexandru I. Cuza' University, Blvd. Carol I, No. 11, Iasi, 700506, Romania.
J Bioenerg Biomembr. 2010 Apr;42(2):173-80. doi: 10.1007/s10863-010-9273-z. Epub 2010 Feb 24.
Little is known on antimicrobial peptide permeation through outer membrane channels in gram-negative bacteria. Herein, we probed at a single-molecule level the interaction of two different peptides, magainin 2 and HPA3P with OmpF from E. coli. HPA3P is an analogue of the antimicrobial peptide HP(2-20) isolated from the N-terminal region of the Helicobacter pylori ribosomal protein. Our data show that the shorter and more charged HPA3P peptide is more accessible to the inner volume of the OmpF than magainin 2. We demonstrate the ability of HPA3P peptides to interact with OmpF in a voltage- and concentration-dependent manner, which does not rule out a novel mechanism by which such peptides could reach the periplasmic space of gram-negative bacteria. Unexpectedly, we found that increasing the applied voltage led to an increase of the residence time of HPA3P peptide inside the pore, possibly reflecting electric field-induced changes in pore and peptide geometry.
关于抗菌肽穿过革兰氏阴性菌外膜通道的机制，目前人们知之甚少。本文从单分子水平探究了两种不同的肽——magainin 2 和 HPA3P 与大肠杆菌 OmpF 的相互作用。HPA3P 是一种抗菌肽 HP(2-20)的类似物，该抗菌肽从幽门螺杆菌核糖体蛋白的 N 端区域分离得到。我们的数据表明，较短且带电荷更多的 HPA3P 肽比 magainin 2 更容易进入 OmpF 的内部体积。我们证明了 HPA3P 肽能够以电压和浓度依赖的方式与 OmpF 相互作用，这不能排除这些肽进入革兰氏阴性菌周质空间的新机制。出乎意料的是，我们发现增加施加的电压会导致 HPA3P 肽在孔内的停留时间增加，这可能反映了电场诱导的孔和肽几何形状的变化。
