Fusing simulation and experiment: The effect of mutations on the structure and activity of the influenza fusion peptide.
During the infection process, the influenza fusion peptide (FP) inserts into the host membrane, playing a crucial role in the fusion process between the viral and host membranes. In this work we used a combination of simulation and experimental techniques to analyse the molecular details of this process, which are largely unknown. Although the FP structure has been obtained by NMR in detergent micelles, there is no atomic structure information in membranes. To answer this question, we performed bias-exchange metadynamics (BE-META) simulations, which showed that the lowest energy states of the membrane-inserted FP correspond to helical-hairpin conformations similar to that observed in micelles. BE-META simulations of the G1V, W14A, G12A/G13A and G4A/G8A/G16A/G20A mutants revealed that all the mutations affect the peptide's free energy landscape. A FRET-based analysis showed that all the mutants had a reduced fusogenic activity relative to the WT, in particular the mutants G12A/G13A and G4A/G8A/G16A/G20A. According to our results, one of the major causes of the lower activity of these mutants is their lower membrane affinity, which results in a lower concentration of peptide in the bilayer. These findings contribute to a better understanding of the influenza fusion process and open new routes for future studies.
ITQB, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal.
Diana
D
Lousa
Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, Av. Professor Egas Moniz, 1649-028 Lisboa, Portugal.
Antónia R T
AR
Pinto
ITQB, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal.
Bruno L
BL
Victor
SISSA/ISAS, Statistical and biological physics, Via Beirut 2-4 Trieste, Italy.
Alessandro
A
Laio
Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, Av. Professor Egas Moniz, 1649-028 Lisboa, Portugal.
Ana S
AS
Veiga
Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, Av. Professor Egas Moniz, 1649-028 Lisboa, Portugal.
Miguel A R B
MA
Castanho
ITQB, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal.
Cláudio M
CM
Soares
D009980:Influenza A virus / Q000502:physiology*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D056004:Molecular Dynamics Simulation; D015394:Molecular Structure; D009154:Mutation; D010455:Peptides / Q000737:chemistry* / Q000235:genetics*; D013050:Spectrometry, Fluorescence; D014760:Viral Fusion Proteins / Q000737:chemistry / Q000235:genetics; D053586:Virus Internalization
D010455:Peptides; D014760:Viral Fusion Proteins