Chemical synthesis, structural and functional characterisation of noxiustoxin, a powerful blocker of lymphocyte voltage-dependent K+ channels.
Two forms of the Centrudoides noxius scorpion noxiustoxin, containing an amidated and an acid C-terminus, were synthesized on a solid support by using Fmoc-chemistry and 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate (HBTU) coupling. Comparison of the two synthetic forms with the native toxin by tryptic mapping and CD spectroscopy shows that noxiustoxin possesses an amidated C-terminus and the same fold as all short scorpion toxins. Patch-clamp assays on B lymphocytes demonstrate that noxiustoxin inhibits the voltage-dependent K+ channels with 2 nM affinity, but does not affect the Ca(2+)-activated K+ channels. This toxin, because of its high affinity and specificity for voltage-gated K+ channel, may provide a powerful tool in the investigation of the role(s) of these channels in the T and B lymphocyte activation and proliferation.
Drakopoulou
E
E
CEA Département d'Ingénierie et d'Etudes des Protéines, CE Saclay, Gif-sur-Yvette, France.
Cotton
J
J
Virelizier
H
H
Bernardi
E
E
Schoofs
A R
AR
Partiseti
M
M
Choquet
D
D
Gurrola
G
G
Possani
L D
LD
Vita
C
C
D000595:Amino Acid Sequence; D000818:Animals; D001402:B-Lymphocytes / Q000187:drug effects* / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D002942:Circular Dichroism; D015640:Ion Channel Gating; D013058:Mass Spectrometry; D051379:Mice; D008969:Molecular Sequence Data; D010449:Peptide Mapping; D026902:Potassium Channel Blockers; D012604:Scorpion Venoms / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D017386:Sequence Homology, Amino Acid
D026902:Potassium Channel Blockers; D012604:Scorpion Venoms; C052567:noxiustoxin