Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, United States of America.
Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, United States of America.
Biochim Biophys Acta Biomembr. 2020 Feb 1;1862(2):183102. doi: 10.1016/j.bbamem.2019.183102. Epub 2019 Oct 31.
Flock House virus (FHV) serves as a model system for understanding infection mechanisms utilized by non-enveloped viruses to transport across cellular membranes. During the infection cycle of FHV, a fundamental stage involves disruption of the endosomal membrane by membrane active peptides, following externalization of the peptides from the capsid interior. The FHV lytic agents are the 44 C-terminal amino acids residues of the capsid protein, which are auto-catalytically cleaved during the capsid maturation process. The cleaved peptides are termed γ peptides. In this study, we perform multi-scale molecular dynamics simulations including 40 μs all-atom molecular dynamics simulations to study the behavior of pre-inserted transmembrane lytic peptides at a high concentration in a neutral membrane. We study the dynamical organization among peptides to form oligomeric bundles in four systems including the wild-type γ peptide and three mutant forms; namely, a truncation mutant in which the 23 C-terminal residues are deleted (γ), a construct where the 8 C-terminal residues of γ are fused to γ (Δ385-399 γ) and a single-point mutant (F402A γ), all of which have been experimentally shown to drastically affect infectivity and lytic activity compared to the wild-type γ. Our results shed light on the actions of varied forms of the FHV lytic peptide including membrane insertion, trans-membrane stability, peptide oligomerization, water permeation activity and dynamic pore formation. Findings from this study provide detailed structural information and rationale for the differences in lytic activity among variants of FHV γ.
禽痘病毒 (FHV) 可作为研究非包膜病毒穿过细胞膜运输的感染机制的模型系统。在 FHV 的感染周期中，一个基本阶段涉及膜活性肽破坏内体膜，随后肽从衣壳内部外翻。FHV 溶细胞剂是衣壳蛋白的 44 个 C 末端氨基酸残基，在衣壳成熟过程中自动催化裂解。裂解的肽称为 γ 肽。在这项研究中，我们进行了包括 40μs 全原子分子动力学模拟在内的多尺度分子动力学模拟，以研究高浓度预插入跨膜溶细胞肽在中性膜中的行为。我们研究了肽之间的动态组织，以在四个系统中形成寡聚束，包括野生型 γ 肽和三种突变形式；即，缺失 23 个 C 末端残基的截断突变体（γ）、将 γ 的 8 个 C 末端残基融合到 γ 中的构建体（Δ385-399γ）和一个单点突变体（F402Aγ），所有这些突变体在感染性和溶细胞活性方面与野生型 γ 相比都有明显的影响。我们的结果阐明了 FHV 溶细胞肽的各种形式的作用，包括膜插入、跨膜稳定性、肽寡聚化、水渗透活性和动态孔形成。这项研究的结果为 FHV γ 变体之间溶细胞活性差异提供了详细的结构信息和原理。
