Nico Taljaard

The complete primary structures of three cytotoxins (CM-6, CM-7 and CM-7A) from Naja naja kaouthia (Siamese cobra) snake venom

Abstract Toxins CM-6, CM-7 and CM-7A were purified from Siamese cobra ( N. n. kaouthia ) venom. They contain 60 amino acids including eight half-cystines and are devoid of glutamic acid or glutamine, histidine and tryptophan. On elucidation of the primary structures, the sequences and invariant amino acids of toxin CM-6, CM-7 and CM-7A appear to resemble those of a group of cytotoxins, which are also devoid of the same four amino acids. In toxin CM-6, CM-7 and CM-7A the ten structurally invariant amino acid residues of the neurotoxins and the cytotoxins are conserved.

The complete primary structures of two reduced and S-carboxymethylated Angusticeps-type toxins from Dendroaspis angusticeps (green mamba) venom☆

Toxins C10S2C2 and C13S1C1 from Dendroaspis angusticeps venom were purified by gel filtration and ion-exchange chromatography. Whereas toxin C10S2C2 comprises 60 amino acids, toxin C13S1C1 contains only 58 but they each include eight half-cystine residues. The complete primary structures of the toxins have been elucidated. The sequences and the invariant amino acids of toxins C10S2C2 and C13S1C1 from D. angusticeps venom resemble those of the angusticeps-type toxins. In the two toxins the ten structurally invariant amino acids of the neurotoxins and cytotoxins are conserved, but the toxins contain none of the three functionally-invariant amino acids of the neurotoxins. Further, the eight cystine residues of the angusticeps-type toxins are in similar locations to those in short neurotoxins of known structure so they are presumed to link similarly. The only structural characteristic of the angusticeps-type toxins which binds them together as a group, is the serine residue in position 5. The toxicities of the angusticeps-type toxins differ among themselves but appear to be of considerably lower toxicity relative to that of the neurotoxin group.

Some properties and the complete primary structures of two reduced and S-carboxymethylated polypeptides (S5C1 and S5C10) from Dendroaspis jamesoni kaimosae (Jameson's mamba) venom

Two polypeptides (protein S5C1 and toxin S5C10) were purified from Dendroaspis jamesoni kaimosae venom. Whereas protein S5C1 comprises 61 amino acid residues, toxin S5C10 contains 58 and they each comprise four disulphide bridges. The complete primary structures of the two polypeptides have been elucidated. The sequences of protein S5C1 and toxin S5C10 are structurally homologous to the short neurotoxins Type I, but they are much less toxic. In toxin S5C10 one of the functionally invariant amino acid residues, lysine 26, of the Type I neurotoxin has been replaced by a serine. In contrast protein S5C1 has the feature that it contains ten or eleven structurally invariant amino acids and apparently only one of the five functionally invariant residues.

Purification, some properties and the primary structures of three reduced and S-carboxymethylated toxins (CM-5, CM-6 and CM-10a) from Naje haje haje (egyptian cobra) venom☆

Three reduced and S-carboxymethylated toxins (CM-5, CM-6 and CM-10a) were purified from Naja haje haje (Egyptian cobra) venom. Whereas toxin CM-5 comprises 71 amino acid residues and five intrachain disulphide bridges, toxins CM-6 and CM-10a contain each 61 residues and four disulphide bridges. The complete primary structures of the three toxins have been established. The toxicity, the immunochemical properties, the sequence and the invariant amino acid residues of toxin CM-5 resemble the properties of the long neurotoxin group, while those of toxin CM-6 and CM-10a are related to the short neurotoxin group. Further, the sequences of the three toxins from Naja haje haje venom reveal a high degree of homology with those of the corresponding neurotoxins isolated from Naja haje annulifera or Naja nivea venoms.

The primary structure of a short neurotoxin homologue (S4C8) from Dendroaspis jamesoni kaimosae (jameson's mamba) venom

1. 1. Toxin S4C8 from Dendroaspis jamesoni kaimosae venom was purified by gel filtration and ion exchange chromatography. It contains 60 amino acids including eight half-cystines. 2. 2. The complete primary structure of toxin S4C8 has been elucidated. The sequence is structurally homologous to the short neurotoxins, but is much less toxic. 3. 3. In toxin S4C8 the ten structurally invariant amino acids of the neurotoxins and cytotoxins are conserved, but it contains only one of the three functionally invariant amino acids of the neurotoxins. 4. 4. The eight cysteinyl residues of toxin S4C8 are in similar locations to those in short neurotoxins of known structures so they are presumed to link similarly.

The complete primary structure of toxin CM-1b from Hemachatus haemachatus (Ringhals) snake venom

Abstract Toxin CM-1b was purified from Hemachatus haemachatus venom. The purified toxin contains 57 amino acids including 8 half-cystine residues in a single polypeptide chain. The complete primary structure of CM-1b has been established. The sequence and the invariant amino acid residues of CM-1b resemble those of the Naja -type toxins. In toxin CM-1b one of the structurally invariant amino acid residues proline 48, of the short neurotoxins has been replaced by a arginine, while it contains none of the functionally invariant amino acid residues.

Naja haje haje (Egyptian cobra) venom Purification, some properties and the amino acid sequences of four toxins (CM-7, CM-8, CM-9, and CM-10b)☆

Four toxins (CM-7, CM-8, CM-9 and CM-10b) were purified from Naja haje haje (Egyptian cobra) venom by gel filtration on Sephadex G-50 followed by ion-exchange chromatography on CM-cellulose. They each contain 60 amino acid residues and are cross-linked by four intrachain disulphide bridges. The complete primary structure of the four toxins have been elucidated. The toxicities, the immunochemical properties, the sequences and invariant amino acid residues opf toxins CM-7, CM-8, CM-9 and CM-10b resemble the corresponding properties of the cytotoxin group.

Sulphhydryl protease inhibitors from pineapple plant stem

Abstract 1. 1. Pineapple stem extract, consisting of a mixture of the protease bromelain and sulphhydryl protease inhibitors, was fractionated by gel permeation chromatography. 2. 2. Inhibitor-containing fractions were further resolved by ion exchange chromatography on DEAE-cellulose, giving 12 chromatographically distinct inhibitory fractions. 3. 3. These 12 inhibitory fractions all show an inhibition specificity towards bromelain. 4. 4. Reduction, S-carboxymethylation and refractionation of each of these inhibitory fractions gave, for each fraction, two separated peptides of ca 13 and 40 amino acids in length, respectively. 5. 5. The amino acid compositions and the N-terminal sequences of these peptides show the inhibitors to be a closely homologous set. Both the constituent peptides of each fraction are microheterogeneous. Each DEAE-cellulose chromatogram peak contains a co-eluting set of iso-inhibitors. 6. 6. Structural microvariations within these isoinhibitors have a minor influence on inhibitor activity towards bromelain.

Gas-phase protein sequencing: gas flow control by positive displacement.

A modification of an automatic gas-phase protein/peptide sequencing apparatus is described; this eliminates the effect of the sample on cell gas flow rates. Consistent sequencing chemistry is achieved, yielding data from material that is intractable using standard equipment.