Chemical synthesis and structure determination of venom toxins

Venom toxins are receiving growing interests as novel therapeutics and biophysical probes. This review briefly discusses recent advances in the chemical synthesis and structure determination of venom toxins.     

Isolation and characterization of neurotoxins from the venom of the spiderAnemesia sp.

Three neurotoxin fractions have been isolated from the venom of the spider Anemesia sp. On interacting with a presynaptic membrane, two of them (An4 and Any) caused an enhancement of the secretion of the mediator and exhaustion of its reserves, while the third (An7) caused suppression of the amplitude of the synaptic potentials.Institute of Physiology and Biophysics, Academy of Sciences of the Republic of Uzbekistan, 700095, Tashkent, ul. Niyazova, 1. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 471–473, May–June, 1995. October 24, 1994.     

Amino-acid composition and terminal amino acids of the toxins of the venom of the central Asian cobra

Conclusions 1. The amino-acid compositions of two neurotoxins from the venom of the Central Asian cobra have been established. The N-terminal amino-acid residue of toxin (I) is isoleucine and that of toxin (II) leucine. There is the same sequence from the C-end of both toxins — Cys-Asn-Asn-COOH.2. The role of the individual functional groups (-amino groups and disulfide bridges) of the amino acids in the lethal action of the toxins has been investigated and discussed.Institute of Biochemistry, Academy of Sciences of the Uzbek SSR. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 62–64, January–February, 1974.     

Investigation of the cardiotoxic peptides of the venom of the cobraNaja oxiana

Six populations of basic polypeptides have been found in the venom of the Central Asian cobraNaja oxiana Eichwald, and four of them — V″c-1, V″c-2, V″c-5, and V″c-6 — have been obtained in the electrophoretically homogeneous state. On a perfused frog heart preparation, all the basic polypeptides proved to be cardiotoxic. However, only some of them (V′c-2, V″c-3, and V″c-4) were characterized by arrhythmic activity as well as by the negative ino- and chronotropic effects, common for all of them. An enhancement of the specific cardiotoxic effect of each of the polypeptides by pure phospholipase A-2 has been shown.     

Investigation of the cardiotoxic peptides of the venom of the cobraNaja oxiana

Six populations of basic polypeptides have been found in the venom of the Central Asian cobraNaja oxiana Eichwald, and four of them — Vc-1, Vc-2, Vc-5, and Vc-6 — have been obtained in the electrophoretically homogeneous state. On a perfused frog heart preparation, all the basic polypeptides proved to be cardiotoxic. However, only some of them (Vc-2, Vc-3, and Vc-4) were characterized by arrhythmic activity as well as by the negative ino- and chronotropic effects, common for all of them. An enhancement of the specific cardiotoxic effect of each of the polypeptides by pure phospholipase A-2 has been shown.Institute of Biochemistry, Academy of Sciences of the Republic of Uzbekistan, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 416–420, May–June, 1994.     

Structure elucidation of a novel family of mycolactone toxins from the frog pathogen Mycobacterium sp. MU128FXT by mass spectrometry

Structures are proposed, based on LC-ion trap MSn analysis and high-resolution FTICR MS/MS analysis, for a novel family of mycolactone toxins isolated from the frog pathogen MU128FXT and differing from those produced by the human pathogen M. ulcerans MUAgy99 in having an altered polyketide side chain.     

Capillary electrophoresis of venoms and toxins.

A review of capillary electrophoresis of venoms and toxins is presented. Emphasis is placed on the analysis of real samples in complex matrices. The structures of some of the complex toxins are presented to illustrate the remarkable diversity and complexity of these materials.     

Marine toxins. Synthesis of the spiro-benzoquinonefuran unit in stypoldione

A synthesis of the unusual spiro-benzoquinonefuran unit (13) presentin the marine toxin stypoldione (1), using the strategy (9) → (10) → (12) → (13), is described.     

Ionspray mass spectrometry of marine toxins. IV. Determination of diarrhetic shellfish poisoning toxins in mussel tissue by liquid chromatography/mass spectrometry.

An improved liquid chromatographic/mass spectrometric (LC/MS) method utilizing gradient elution and ion-spray ionization is described for the sensitive determination of okadaic acid and dinophysistoxin-1, the principal toxins implicated in cases of diarrhetic shellfish poisoning. The method was used to confirm the presence of both toxins, together with a recently identified isomer of okadaic acid, dinophysistoxin-2, in various samples of cultivated blue mussels (Mytilus edulis) from Canadian and European waters. The method provided a mass detection limit of 0.4 ng for each toxin, thus allowing detection of 40 ng per g of whole mussel tissue (or approximately 10 ng/g if only the digestive glands were used in the assay). Quantitative results obtained by LC/MS were in good agreement with those obtained by derivatization and high-performance liquid chromatography with fluorescence detection.     

Comparison of denitrification between Paracoccus sp. and Diaphorobacter sp

Denitrification was compared between Paracoccus sp. and Diaphorobacter sp. in this study, both of which were isolated from activated sludge of a denitrifying reactor. Denitrification of both isolates showed contrasting patterns, where Diaphorobacter sp. showed accumulation of nitrite in the medium while Paracoccus sp. showed no accumulation. The nitrate reduction rate was 1.5 times more than the nitrite reduction in Diaphorobacter sp., as analyzed by the resting state denitrification kinetics. Increasing the nitrate concentration in the medium increased the nitrite accumulation in Diaphorobacter sp., but not in Paracoccus sp., indicating a branched electron transfer during denitrification. Diaphorobacter sp. was unable to denitrify efficiently at high nitrate concentrations from 1 M, but Paracoccus sp. could denitrify even up to 2 M nitrate. Paracoccus sp. was found to be an efficient denitrifier with insignificant amounts of nitrite accumulation, and it could also denitrify high amounts of nitrate up to 2 M. Efficient denitrification without accumulation of intermediates like nitrite is desirable in the removal of high nitrates from wastewaters. Paracoccus sp. is shown to suffice this demand and could be a potential organism to remove high nitrates effectively.     

Cercospora beticola toxins. NMR studies and chemical behaviour

In this paper we have gathered NMR data on a series of identified beticolins, as well as the chemical and spectroscopic criteria allowing the differentiation of o- and p-beticolins. Spectroscopic criteria are based on the observation of characteristic nOe’s for both forms, whilst chemical criteria are derived from the behaviour of beticolins when exposed to a basic medium and from their ability to form stable dimers binding two Mg atoms.