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The purification and amino acid sequences of four Tx2 neurotoxins from the venom of the Brazilian ‘armed’ spider Phoneutria nigriventer (Keys)
Author(s) -
Cordeiro Marta do Nascimento,
Diniz Carlos Ribeiro,
do Carmo Valentim Ana,
von Eickstedt Vera Regina D.,
Gilroy John,
Richardson Michael
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)81318-g
Subject(s) - chemistry , amino acid , magainin , biochemistry , peptide , antimicrobial peptides
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 .