Binding properties of (3)H-PbTx-3 and (3)H-saxitoxin to brain membranes and to skeletal muscle membranes of puffer fish Fugu pardalis and the primary structure of a voltage-gated Na(+) channel alpha-subunit (fMNa1) from skeletal muscle of F. pardalis.
The dissociation constants for (3)H-saxitoxin to brain membranes and to skeletal muscle membranes of puffer fish Fugu pardalis have been estimated to be 190- and 460-fold, respectively, larger than those to corresponding membranes of rat, by a rapid filtration assay, while these values for (3)H-PbTx-3 have been estimated to be one-third and one-half of those to rat, respectively. We have obtained a cDNA, encoding an entire voltage-gated Na(+) channel alpha-subunit (fMNa1, 1880 residues) from skeletal muscle of F. pardalis by composition of the fragments obtained from cDNA library and RT-PCR products. In fMNa1 protein, the residues for ion-selective filter and voltage sensor and the charged residues in SS2 regions of domains I-IV were conserved, but the aromatic amino acid (Phe/Tyr), commonly located in the SS2 region of domain I of tetrodotoxin-sensitive Na(+) channels, was replaced by Asn. With this particular criterion, we propose that the fMNa1 protein is a tetrodotoxin-resistant Na(+) channel.
Yotsu-Yamashita
M
M
Graduate School of Agriculture, Tohoku University, Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai, 981-8555, Japan. myama@biochem.tohoku.ac.jp
Nishimori
K
K
Nitanai
Y
Y
Isemura
M
M
Sugimoto
A
A
Yasumoto
T
T
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D019143:Evolution, Molecular; D005399:Fishes; D006801:Humans; D007700:Kinetics; D008387:Marine Toxins / Q000493:pharmacokinetics*; D008969:Molecular Sequence Data; D018482:Muscle, Skeletal / Q000378:metabolism*; D009466:Neuromuscular Blocking Agents / Q000493:pharmacokinetics*; D035964:Oxocins; D010802:Phylogeny; D011869:Radioligand Assay; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012530:Saxitoxin / Q000493:pharmacokinetics*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D015222:Sodium Channels / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D013570:Synaptic Membranes / Q000378:metabolism*; D014316:Tritium; D000095702:Polyether Toxins
D008387:Marine Toxins; D009466:Neuromuscular Blocking Agents; D035964:Oxocins; D012530:Saxitoxin; D015222:Sodium Channels; D014316:Tritium; C041017:brevetoxin T17; D000095702:Polyether Toxins