Mutagenesis and nuclear magnetic resonance analyses of the fusion peptide of Helicoverpa armigera single nucleocapsid nucleopolyhedrovirus F protein.
The entry of enveloped viruses into cells is normally mediated by fusion between viral and cellular membranes, in which the fusion peptide plays a crucial role. The fusion peptides of group II nucleopolyhedrovirus (NPV) F proteins are quite conserved, with a hydrophobic region located at the N terminal of the F(1) fragment. For this report, we used mutagenesis and nuclear magnetic resonance (NMR) to study the structure and function of the fusion peptide of the Helicoverpa armigera single-nucleocapsid NPV (HearNPV) F protein (HaF). Five mutations in the fusion peptide of HaF, N(1)G, N(1)L, I(2)N, G(3)L, and D(11)L, were generated separately, and the mutated f genes were transformed into the f-null HearNPV bacmid. The mutations N(1)L, I(2)N, and D(11)L were found to completely abolish the ability of the recombinant bacmids to produce infectious budded virus, while the mutations N(1)G and G(3)L did not. The low-pH-induced envelope fusion assay demonstrated that the N(1)G substitution increased the fusogenicity of HaF, while the G(3)L substitution reduced its fusogenicity. NMR spectroscopy was used to determine the structure of a synthetic fusion peptide of HaF in the presence of sodium dodecyl sulfate micelles at pH 5.0. The fusion peptide appeared to be an amphiphilic structure composed of a flexible coil in the N terminus from N(1) to N(5), a 3(10)-helix from F(6) to G(8), a turn at S(9), and a regular alpha-helix from V(10) to D(19). The data provide the first NMR structure of a baculovirus fusion peptide and allow us to further understand the relationship of structure and function of the fusion peptide.
State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, People's Republic of China.
Ying
Y
Tan
Ling
L
Jiang
Manli
M
Wang
Feifei
F
Yin
Fei
F
Deng
Maili
M
Liu
Zhihong
Z
Hu
Hualin
H
Wang
D000595:Amino Acid Sequence; D000818:Animals; D019295:Computational Biology; D006863:Hydrogen-Ion Concentration; D007313:Insecta / Q000821:virology*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008968:Molecular Conformation; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D019251:Nucleocapsid / Q000737:chemistry*; D017924:Nucleopolyhedroviruses / Q000378:metabolism*; D010455:Peptides / Q000737:chemistry; D017433:Protein Structure, Secondary; D017386:Sequence Homology, Amino Acid
D010455:Peptides