Nakamura M, Ishida Y, Kohno T, Sato K, Oba Y, Nakamura H
Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa-ku, Nagoya, 464-8601, Japan.
J Pept Res. 2004 Sep;64(3):110-7. doi: 10.1111/j.1399-3011.2004.00175.x.
Mu-conotoxin GIIIA, a peptide toxin from the cone snail, blocks muscle-type sodium channels. Thr-5 of mu-conotoxin GIIIA, located on the opposite side of the active site in the globular molecule, was replaced by Cys to which the bulky tags were attached. The tagged mu-conotoxin GIIIA derivatives, except for the phospholipid-tagged one, exerted the biological activity with a potency slightly weaker than natural mu-conotoxin GIIIA. When the biotinylated tags of various lengths were added, the presence of avidin suppressed the action of the biotinylated toxins of <4 nm, but not with 5 nm. The bulky biotinylated tags are useful as a caliper to measure the depth of receptor sites in the channels.
