Characterization of inhibition of M2 ion channel activity by BL-1743, an inhibitor of influenza A virus.
The influenza A virus M2 integral membrane protein has ion channel activity that can be inhibited by the antiviral drug amantadine. Recently, a spirene-containing compound, BL-1743 (2-[3-azaspiro (5,5)undecanol]-2-imidazoline), that inhibits influenza virus growth was identified (S. Kurtz, G. Lao, K. M. Hahnenberger, C. Brooks, O. Gecha, K. Ingalls, K.-I. Numata, and M. Krystal, Antimicrob. Agents Chemother. 39:2204-2209, 1995). We have examined the ability of BL-1743 to inhibit the M2 ion channel when expressed in oocytes of Xenopus laevis. BL-1743 inhibition is complete as far as can be measured by electrophysiological methods and is reversible, with a reverse reaction rate constant of 4.0 x 10(-3) s(-1). In contrast, amantadine inhibition is irreversible within the time frame of the experiment. However, BL-1743 inhibition and amantadine inhibition have similar properties. The majority of isolated influenza viruses resistant to BL-1743 are also amantadine resistant. In addition, all known amino acid changes which result in amantadine resistance also confer BL-1743 resistance. However, one BL-1743-resistant virus isolated, designated M2-I35T, contained the change Ile-35-->Thr. This virus is >70-fold more resistant to BL-1743 and only 10-fold more resistant to amantadine than the wild-type virus. When the ion channel activity of M2-I35T was examined in oocytes, it was found that M2-I35T is BL-1743 resistant but is reversibly inhibited by amantadine. These findings suggest that these two drugs interact differently with the M2 protein transmembrane pore region.
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Department of Neurobiology and Physiology, Northwestern University, Evanston, Illinois, 60208-3520, USA.
Pinto
L H
LH
Luo
G
G
Shaughnessy
M A
MA
Mullaney
D
D
Kurtz
S
S
Krystal
M
M
Lamb
R A
RA
D000547:Amantadine / Q000494:pharmacology; D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology*; D001483:Base Sequence; D002460:Cell Line; D017931:DNA Primers; D004285:Dogs; D005260:Female; D007093:Imidazoles / Q000493:pharmacokinetics*; D009980:Influenza A virus / Q000187:drug effects* / Q000378:metabolism; D007473:Ion Channels / Q000037:antagonists & inhibitors*; D008969:Molecular Sequence Data; D009154:Mutation; D013141:Spiro Compounds / Q000493:pharmacokinetics*; D014763:Viral Matrix Proteins / Q000037:antagonists & inhibitors*; D014982:Xenopus laevis; D000086082:Viroporin Proteins
D000547:Amantadine; D000998:Antiviral Agents; D017931:DNA Primers; D007093:Imidazoles; D007473:Ion Channels; D013141:Spiro Compounds; D014763:Viral Matrix Proteins; C100337:2-(3-azaspiro(5,5)undecanol)-2-imidazoline; C031540:M-protein, influenza virus; C488937:M2 protein, Influenza A virus; D000086082:Viroporin Proteins