The purification and amino acid sequences of four Tx2 neurotoxins from the venom of the Brazilian 'armed' spider Phoneutria nigriventer (Keys)
Abstract
Four neurotoxic polypeptides (Tx2.1, Txt2-5, Tx2-6 and Tx2-9) were purified from the venom of the South American 'armed' spider Phoneutria nigriventer (Keys) by gel filtration and reverse phase FPLC and HPLC. These cysteine-rich polypeptides exhibited different levels of neurotoxicity in mice after intracerebroventricular injection. Tx2-1, Tx2-5 and Tx2-6 caused spastic paralysis and death, but the less toxic Tx2-9 produced only tail erection and scratching. The molecular weights of the polypeptides as determined by desorption mass spectroscoopy were 5838.8 for Tx2-1, 5116.6 (Tx2-5), 5291.3 (Tx2-6) and 3742.1 (Tx2-9). The complete amino acid sequences of the neurotoxins were determined by automated Edman degradation and by manual DABITC-PITC microseqeunce analysis of peptides obtained after digestions with various proteases. The amino acid sequences of Tx2-1 (53 residues), Tx2-5 (48 residues) and Tx2-6 (48 residues) were homologous, but had only limited similarities to the less toxic Tx2-9 (32 residues). All four polypeptides had varying sequence identities with other neurotoxins from different spider species and biologically active peptides from scorpions, a sea snail and seeds of Mirabilis jalapa.
- Publication:
-
FEBS Letters
- Pub Date:
- January 1992
- DOI:
- 10.1016/0014-5793(92)81318-G
- Bibcode:
- 1992FEBSL.310..153C
- Keywords:
-
- Spider venom;
- Amino acid sequence;
- Neurotoxin;
- Phoneutria nigriventer