Cell-Selective Pore Forming Antimicrobial Peptides of the Prodomain of Human Furin: A Conserved Aromatic/Cationic Sequence Mapping, Membrane Disruption, and Atomic-Resolution Structure and Dynamics

Antimicrobial
peptides are promising molecules in uprising consequences
of drug-resistant bacteria. The prodomain of furin, a serine protease,
expressed in all vertebrates including humans, is known to be important
for physiological functions. Here, potent antimicrobial peptides were
mapped by extensive analyses of overlapping peptide fragments of the
prodomain of human furin. Two peptides, YR26 and YR23, were active
against bacterial cells including MRSA-resistant Staphylococcus
aureus and Staphylococcus epidermis 51625. Peptides were largely devoid of hemolytic and cytotoxic activity.
Bacterial cell killing occurred as a result of the disruption of the
permeability barrier of the lipopolysaccharide (LPS)-outer membrane
and fragmentation of LPS into small micelles. Furthermore, antibacterial
peptides specifically interacted with the negatively charged lipids
causing membrane leakage and fusion. The YR26 peptide in sodium dodecyl
sulfate micelles demonstrated a long-helix-turn-short-helix structure
exhibiting restricted backbone motions. The cell-selective activity
of the furin peptides and their unique mode of action on membranes
have a significant potential for the development of therapeutics.

抗菌肽（Antimicrobial peptides）是应对耐药细菌日益严峻问题的极具前景的候选分子。弗林蛋白酶（furin）作为一种丝氨酸蛋白酶，其前结构域在包括人类在内的所有脊椎动物体内均有表达，且已被证实对生理功能至关重要。本研究通过对人类弗林蛋白酶前结构域的重叠肽片段进行广泛分析，成功筛选得到强效抗菌肽。本次鉴定出的YR26与YR23两种肽段，对包括耐甲氧西林金黄色葡萄球菌（MRSA）及表皮葡萄球菌51625在内的多种细菌均具有抗菌活性。上述肽段几乎无溶血活性与细胞毒性。其杀菌机制为破坏脂多糖（lipopolysaccharide, LPS）外膜的通透性屏障，并将LPS裂解为小型胶束。此外，该类抗菌肽可与带负电荷的脂质特异性结合，引发细胞膜渗漏与融合。在十二烷基硫酸钠（sodium dodecyl sulfate, SDS）胶束环境中，YR26肽段呈现出长螺旋-转角-短螺旋的结构，且其主链运动受到限制。弗林蛋白酶衍生肽段的细胞选择性活性及其独特的膜作用模式，为抗菌治疗药物的开发提供了巨大潜力。