[Polypeptide toxin from sea anemone inhibiting proton-sensitive channel ASIC3].

Polypeptide toxin pi-AnmTX Hcr 1b-1 with a molecular weight 4537 Da was isolated from the whole body extract of sea anemone by a multistage liquid chromatography. The BLAST search algorithm revealed homology of the novel toxin amino acid sequence to the group of the known sea anemone toxins including BDS and APETx with similarity less then 50%. The toxin pi-AnmTX Hcr 1b-1 inhibited the amplitude of the fast component of integral ASIC3 current in electrophysiological studies on receptors expressed in Xenopus laevis oocytes. The calculated IC50 value was 5.5 +/- 1.0 microM. Among the known polypeptide toxins interacted with ASICs channels, the micro-AnmTX Hcr 1b-1 toxin is the least potent inhibitor that in our opinion correlates with a small amount of charged amino acid residues in its structure.

[Association study of the SCN1 gene polymorphism and effective dose of lamotrigine].

An association between a polymorphism of the SCN1 gene, a therapeutical target of lamotrigine, and an effective dose (a blood plasma concentration) of the drug in patients with epilepsy has been studied. Fifty patients with different forms of epilepsy have been genotyped for the SCN1 IVS5N+5 G>A polymorphism using polymerase chain reaction. The distribution of allelic variants was as follows: 23 patients had the mutant homozygous genotype (V/V), 20 - the heterozygous genotype Wt/V and 7 were homozygous for the wild allele (Wt/Wt). Mean lamotrigine doses were 85,7+/-7,4 mg/day for carriers of the Wt/Wt genotype, 113,75+/-7,13 mg/day for the Wt/V genotype and 142,4+/-15,43 mg/day for the V/V genotype. Peak plasma concentrations corresponded to effective doses were 0,6+/-0,065 mg/ml for Wt/Wt, 0,96+/-0,1 mg/ml for V/V and 0,72+/-0,1 mg/ml for Wt/V. The hypothesis on the association between the SCN1 IVS5N+5 G>A polymorphism and the effective dose (concentration) of lamotrigine was confirmed. The significantly higher frequency of the SCN1A mutation in the group of patients with epilepsy compared to the control group of Caucasians (45,5 and 21,3%, respectively) implies that this polymorphism may contribute to the pathogenesis of epilepsy.

[New polypeptide components from the Heteractis crispa sea anemone with analgesic activity].

Two new polypeptide components which exhibited an analgesic effect in experiments on mice were isolated from the Heteractis crispa sea tropical anemone by the combination of chromatographic methods. The APHC2 and APHC3 new polypeptides consisted of 56 amino acid residues and contained six cysteine residues. Their complete amino acid sequence was determined by the methods of Edman sequencing, mass spectrometry, and peptide mapping. An analysis of the primary structure of the new peptides allowed for their attribution to a large group of trypsin inhibitors of the Kunitz type. An interesting biological function of the new polypeptides was their analgesic effect on mammals, which is possibly realized via the modulation of the activity of the TRPV1 receptor and was not associated with the residual inhibiting activity towards trypsin and chymotrypsin. The analgesic activity of the APHC3 polypeptide was measured on the hot plate model of acute pain and was significantly higher than that, of APHC2. Methods of preparation of the recombinant analogues were created for both polypeptides.

[Alternative splicing of pre-mRNA encoding the Musca domestica latrophilin-like protein(LLP): primary structures of four spliced forms of mRNA and their protein products].

An internal DNA fragment (approximately 2000 bp) homologous to the conserved regions of genes encoding latrophilin-like proteins (LLPs) was obtained by the PCR technique using degenerate primers to these gene regions. The gene-specific primers were synthesized based on the results of sequencing of the isolated fragment, and all overlapping cDNA fragments of the llp gene encoding the Musca domestica LLP were obtained by the rapid amplification of cDNA 5'- and 3'-ends (5'- and 3'-RACE). Four alternatively spliced mRNAs were found while sequencing the obtained cDNA fragments. Two long mRNAs (approximately 6000 nt) differ in the structures of both the sites encoding signal peptides and 5'-terminal untranslated regions. They encode large proteins (approximately 1800 aa), whose domain organization is similar to that of mammalian latrophilins. Each deduced protein contains a domain with seven transmembrane regions followed by an extended cytoplasmic C-terminal domain. Two other mRNA forms are derived from these long mRNAs; they encode proteins severly truncated at their C-termini (approximately 900 aa). They are composed of only three transmembrane regions and a short unique cytoplasmic C-terminal domain (23 aa). The limitations and drawbacks of the existing 3'-RACE techniques found during study of the long alternatively spliced cDNAs are analyzed, and ways for overcoming these difficulties are proposed.