Ion channels formed by NB, an influenza B virus protein.
The influenza B virus protein, NB, was expressed in Escherichia coli, either with a C-terminal polyhistidine tag or with NB fused to the C-terminus of glutathione S-transferase (GST), and purified by affinity chromatography. NB produced ion channel activity when added to artificial lipid bilayers separating NaCl solutions with unequal concentrations (150-500 mM cis, 50 mM trans). An antibody to a peptide mimicking the 25 residues at the C-terminal end of NB, and amantadine at high concentration (2-3 mM), both depressed ion channel activity. Ion channels had a variable conductance, the lowest conductance observed being approximately 10 picosiemens. At a pH of 5.5 to 6.5, currents reversed at positive potentials indicating that the channel was more permeable to sodium than to chloride ions (PNa/PCl approximately 9). In asymmetrical NaCl solutions at a pH of 2.5, currents reversed closer to the chloride than to the sodium equilibrium potential indicating that the channel had become more permeable to chloride than to sodium ions (PCl/PNa approximately 4). It was concluded that, at normal pHs, NB forms cation-selective channels.
Sunstrom
N A
NA
John Curtin School of Medical Research, Australian National University, Canberra, Australia.
Premkumar
L S
LS
Premkumar
A
A
Ewart
G
G
Cox
G B
GB
Gage
P W
PW
D000547:Amantadine / Q000494:pharmacology; D000818:Animals; D004553:Electric Conductivity; D006023:Glycoproteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D006801:Humans; D009981:Influenza B virus / Q000378:metabolism*; D007473:Ion Channels / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008051:Lipid Bilayers; D011817:Rabbits; D011993:Recombinant Fusion Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D014764:Viral Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*
D006023:Glycoproteins; D007473:Ion Channels; D008051:Lipid Bilayers; C051094:NB glycoprotein, Influenza B virus; D011993:Recombinant Fusion Proteins; D014764:Viral Proteins; D000547:Amantadine