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Site directed mutants of Noxiustoxin reveal specific interactions with potassium channels
Author(s) -
Martı́nez F.,
Muñoz-Garay C.,
Gurrola G.,
Darszon A.,
Possani L.D.,
Becerril B.
Publication year - 1998
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(98)00636-x
Subject(s) - alanine , tripeptide , threonine , xenopus , mutant , alanine scanning , arginine , amino acid , chemistry , biochemistry , cysteine , serine , aspartic acid , recombinant dna , potassium channel , biology , biophysics , mutagenesis , gene , phosphorylation , enzyme
Several site directed mutations were introduced into a synthetic Noxiustoxin (NTX) gene. Alanine scanning of the nonapeptide at the N‐terminal segment of NTX (threonine 1 (T1) to serine 9 (S9)) was constructed and the recombinant products were obtained in pure form. Additionally, lysine 28 (K28) was changed to arginine (R) or glutamic acid (E), cysteine 29 was changed to alanine, and residues 37–39 (Tyr‐Asn‐Asn) of the carboxyl end were deleted. The recombinant mutants were tested for their ability to displace 125 I‐NTX from rat brain synaptosome membranes, as well as for their efficiency in blocking the activity of K v 1.1 K + channels expressed in Xenopus laevis oocytes. The main results indicate that residues K6, T8 at the amino end, and K28 and the tripeptide YNN at the carboxyl end are involved in specific interactions of NTX with rat brain and/or K v 1.1 K + channels.