TAILIEUCHUNG - Báo cáo khoa học: The first representative of glycosylated three-fingered toxins

There are different glycosylated proteins in snake venoms, but no glycosylated representatives of a large family of three-fingered toxins have previously been detected. A new glycoprotein was isolated from the venom of the Thai cobra Naja kaouthia. MALDI MS of the glycoprotein contained an array of peaks in the range from 8900 to 9400 Da indicating its microheterogeneity. Carbohy-drate analysis showed the presence of mannose, galactose, N-acetylglucosamine, fucose and neuraminic acid. | Eur. J. Biochem. 271 2018-2027 2004 FEBS 2004 doi The first representative of glycosylated three-fingered toxins Cytotoxin from the Naja kaouthia cobra venom Alexey V. Osipov Maria V. Astapova Victor I. Tsetlin and Yuri N. Utkin Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry Russian Academy of Sciences Moscow Russia There are different glycosylated proteins in snake venoms but no glycosylated representatives of a large family of three-fingered toxins have previously been detected. A new glycoprotein was isolated from the venom of the Thai cobra Naja kaouthia. MALDI MS of the glycoprotein contained an array of peaks in the range from w 8900 to w 9400 Da indicating its microheterogeneity. Carbohydrate analysis showed the presence of mannose galactose N-acetylglucosamine fucose and neuraminic acid. The N-terminal sequence of the glycoprotein was identical to that of cytotoxin 3 CX3 from N. kaouthùi and CD spectra of the glycoprotein and CX3 were almost the same. Cleavage of a glycan moiety by N-glycosidase F gave a protein of molecular mass practically coinciding with that of CX3. MALDI MS of the tryptic digest of reduced glycoprotein S-pyridylethylated at cysteine residues contained peaks corresponding to all tryptic fragments of CX3 with the exception of fragment 24-30. The peak corresponding to this peptide appeared in the massspectrum of similarly treated deglycosylated glycoprotein. These data show that the potential N-glycosylation site at Asn29 in CX3 is utilized for glycan attachment and that the glycoprotein is glycosylated CX3. In vivo toxicity of the glycoprotein to the cricket Gryllus assimilis was twofold lower than that of CX3. The cytotoxic activity of the glycoprotein towards HL60 cells was about two orders of magnitude lower than that of CX3 but could be made equal to the CX3 cytotoxicity by deglycosylation. Thus for the first time we have isolated a glycosylated three-fingered snake venom toxin wherein .

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