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Identification of an ion channel‐forming motif in the primary structure of tetanus and botulinum neurotoxins
Author(s) -
Monta Myrta S.,
Blewitt Richard,
Tomich John M.,
Montal Mauricio
Publication year - 1992
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 - 10.1016/0014-5793(92)81173-j
Subject(s) - tetanus , protein primary structure , motif (music) , chemistry , ion channel , computational biology , biochemistry , biology , peptide sequence , virology , gene , receptor , physics , vaccination , acoustics
Synthetic peptides with amino acid sequences corresponding to predicted transmembrane segments of tetanus toxin were used as probes to identify a channel‐forming motif. A peptide denoted TeTx II, with sequence GVVLLLEYIPEITLPVIAALSIA, forms cation‐selective channels when reconstituted in planar lipid bilayers. The single channel conductance in 0.5 M NaCl or KCl is 28 ± 3 and 24 ± 2 pS, respectively. In contrast, a peptide with sequence NFIGALETTGVVLLLEYIPEIT, denoted as TeTx I. or a peptide with the same amino acid composition as TeTx II but with a randomized sequence, do not form channels. Conformational energy calculations show that a bundle of four amphipathic α‐helices is a plausible structural motif underlying observable pore properties. The identified functional module may account for the channel‐forming activity of both tetanus toxin and the homologous botulinum toxin A.