tetano
Editor, Senior Moderator
J Virol. 2015 Dec 16. pii: JVI.02326-15. [Epub ahead of print]
[h=1]Identification of Novel Fusion Inhibitors of Influenza A Virus by Chemical Genetics.[/h] Lai KK[SUP]1[/SUP], Cheung NN[SUP]1[/SUP], Yang F[SUP]1[/SUP], Dai J[SUP]1[/SUP], Liu L[SUP]2[/SUP], Chen Z[SUP]3[/SUP], Sze KH[SUP]4[/SUP], Chen HL[SUP]4[/SUP], Yuen KY[SUP]5[/SUP], Kao RY[SUP]5[/SUP].
[h=3]Author information[/h]
[h=3]Abstract[/h] A previous screening of more than 50,000 compounds led to the identification of a pool of bioactive small molecules with inhibitory effect on the influenza A virus. One of these compounds, now widely known as Nucleozin, is a small molecule that targets the influenza A nucleoprotein. Herein we identify and characterize two structurally different novel fusion inhibitors of the influenza A group 1 hemagglutinin, FA-583 and FA-617, with low nanomolar activities. Highly resistant escape mutants against each of these compounds were generated and both were found to carry mutations localized in close proximity to the B-loop of the hemagglutinin 2 protein, which plays a crucial role in the virion-host cell fusion process. Recombinant virus, generated through reverse genetics, confirmed the resistant phenotype. In addition, the proposed binding pockets predicted by molecular docking studies are in accordance with the resistance-bearing mutation sites. We show through mechanistic studies that FA-583 and FA-617 act as fusion inhibitors by prohibiting the low pH-induced conformational change of hemagglutinin. Our study has offered concrete biological and mechanistic explorations for the strategic development of novel fusion inhibitors of influenza A viruses.
[h=4]IMPORTANCE:[/h] Here we report two structurally distinctive novel fusion inhibitors of influenza A virus that act by interfering with the structural change of HA at acidic pH, a process necessary for successful entry of the virus. Mutational and molecular docking studies have identified their binding pockets closely situated to the B-loop region of hemagglutinin 2. The reduced sensitivity of FA-583- or FA-617-associated mutants to another compound suggests close proximity and even partially overlapping of their binding sites on hemagglutinin. Amino acid sequence alignments and crystal structures of group 1 and group 2 hemagglutinins have shed light on the possible binding mode of these two compounds. This report offers new lead compounds for the design of fusion inhibitors for influenza A viruses and further shows that forward chemical genetics is a highly effective approach for the identification of novel compounds that can perturb the infectivity of viruses and to probe new druggable targets or druggable domains in various viruses.
Copyright ? 2015, American Society for Microbiology. All Rights Reserved.
PMID: 26676787 [PubMed - as supplied by publisher]
[h=1]Identification of Novel Fusion Inhibitors of Influenza A Virus by Chemical Genetics.[/h] Lai KK[SUP]1[/SUP], Cheung NN[SUP]1[/SUP], Yang F[SUP]1[/SUP], Dai J[SUP]1[/SUP], Liu L[SUP]2[/SUP], Chen Z[SUP]3[/SUP], Sze KH[SUP]4[/SUP], Chen HL[SUP]4[/SUP], Yuen KY[SUP]5[/SUP], Kao RY[SUP]5[/SUP].
[h=3]Author information[/h]
[h=3]Abstract[/h] A previous screening of more than 50,000 compounds led to the identification of a pool of bioactive small molecules with inhibitory effect on the influenza A virus. One of these compounds, now widely known as Nucleozin, is a small molecule that targets the influenza A nucleoprotein. Herein we identify and characterize two structurally different novel fusion inhibitors of the influenza A group 1 hemagglutinin, FA-583 and FA-617, with low nanomolar activities. Highly resistant escape mutants against each of these compounds were generated and both were found to carry mutations localized in close proximity to the B-loop of the hemagglutinin 2 protein, which plays a crucial role in the virion-host cell fusion process. Recombinant virus, generated through reverse genetics, confirmed the resistant phenotype. In addition, the proposed binding pockets predicted by molecular docking studies are in accordance with the resistance-bearing mutation sites. We show through mechanistic studies that FA-583 and FA-617 act as fusion inhibitors by prohibiting the low pH-induced conformational change of hemagglutinin. Our study has offered concrete biological and mechanistic explorations for the strategic development of novel fusion inhibitors of influenza A viruses.
[h=4]IMPORTANCE:[/h] Here we report two structurally distinctive novel fusion inhibitors of influenza A virus that act by interfering with the structural change of HA at acidic pH, a process necessary for successful entry of the virus. Mutational and molecular docking studies have identified their binding pockets closely situated to the B-loop region of hemagglutinin 2. The reduced sensitivity of FA-583- or FA-617-associated mutants to another compound suggests close proximity and even partially overlapping of their binding sites on hemagglutinin. Amino acid sequence alignments and crystal structures of group 1 and group 2 hemagglutinins have shed light on the possible binding mode of these two compounds. This report offers new lead compounds for the design of fusion inhibitors for influenza A viruses and further shows that forward chemical genetics is a highly effective approach for the identification of novel compounds that can perturb the infectivity of viruses and to probe new druggable targets or druggable domains in various viruses.
Copyright ? 2015, American Society for Microbiology. All Rights Reserved.
PMID: 26676787 [PubMed - as supplied by publisher]