Synthetic peptides corresponding to the sequence of noxiustoxin indicate that the active site of this K+ channel blocker is located on its amino-terminal portion |
| |
Authors: | G B Gurrola R Molinar-Rode M Sitges A Bayon L D Possani |
| |
Institution: | (1) Present address: Departamento de Bioquímica, Centro de Investigación sobre Ingeniería Genética y Biotecnología, UNAM, Cuernavaca, Morelos, México;(2) Departamento de Biología Molecular, Instituto de Investigaciones Biomédicas, UNAM, México;(3) Instituto Mexicano de Psiquiatría, Unidad de Neuroquímica Analítica, México |
| |
Abstract: | Summary A nonapeptide Thr-Ile-Ile-Asn-Val-Lys-Cys-Thr-Ser (NTX1–9) and a decapeptide Met-Asn-Gly-Lys-Cys-Lys-Cys-Tyr-Asn-Asn (NTX30–39) corresponding to the N-terminal and C-terminal sequences respectively of Noxiustoxin (NTX) were synthesized by the solid phase method of Merrifield (1963). The first synthetic peptide (NTX1–9) was shown to be toxic to mice independently of the route of administration: intraperitoneally, subcutaneously or intraventricularly (100–200 g/20 g mouse weight). The second (NTX30–39) was not toxic even at higher dose (400 g/20 g mouse). When the effects of the peptide NTX1–9 and of the authentic toxin (Noxiustoxin) were studied on the liberation of 3H] 4-aminobutyric acid (3H-GABA) from mouse synaptosomes, both gave essentially the same results, except that peptide NTX1–9 was needed at higher concentration. Synthetic peptide NTX30–39 had no effect in the same preparation at even higher doses. The GABA release produced by toxic peptide NTX1–9 was not affected by tetrodotoxin but was completely abolished by the presence of the K+ ionophore valinomycin, mimicking the effect of native NTX in the same system (Sitges et al., 1986). These results indicate that the toxic active site of Noxiustoxin is possibly located in or near the N-terminal amino acid portion of the molecule.Abbreviations used BOC
amino acids ter-butyloxycarbonyl-amino acids
- BOC
amino acid-PAM-resin ter-butyloxycarbonyl-aminoacyl-4-(oxymethyl)-phenacetamidomethyl-resin
- GABA 4
aminobutyric acid
- HPLC
high performance liquid chromatography
- MSA
mouse serum albumin
- NTX
Noxiustoxin
- NTX
(numbers) synthetic peptides with amino acid sequences of NTX at position start (first number) to position end (second number) of the sequence according to Fig. 1
- TTX
tetrodotoxin
Supported in part by the Mexican Council of Science and Technology (CONACyT), grants PVT/QF/NAL/84/2182, PVT/AI/NAL/85/3029 to L.D.P.; PCSACNA 022640 to A.B. A patent request claiming rights on the use of synthetic NTX and related peptides was presented in Washington, DC (U.S.A.), Serial number 07/132,169, filing date December 14, 1987. |
| |
Keywords: | Scorpion toxins noxiustoxin K+ channels synthetic peptide |
本文献已被 SpringerLink 等数据库收录! |
|