[Synthetic analogues of antimicrobial peptides from the venom of the Central Asian spider Lachesana tarabaevi].

Analogues of latarcins Ltc1 and Ltc3b, antimicrobial peptides from the venom of the Central Asian spider Lachesana tarabaevi capable of formation of amphiphilic structures in membranes without involvement of disulfide bonds, were synthesized. The amino acid sequences of the analogues correspond to immature forms of these peptides, each of them containing an additional C-terminal amino acid residue. It is concluded from the study of the biological activity of the synthesized peptides that the posttranslational C-terminal amidation of Ltc3b is a functionally important modification that ensures a high activity of the mature peptide.

Antiamoebin I in methanol solution: rapid exchange between right-handed and left-handed 3(10)-helical conformations.

Antiamoebin I (Aam-I) is a membrane-active peptaibol antibiotic isolated from fungal species belonging to the genera Cephalosporium, Emericellopsis, Gliocladium, and Stilbella. Antiamoebin I has the amino acid sequence: Ac-Phe(1)-Aib-Aib-Aib-Iva-Gly-Leu-Aib(8)-Aib-Hyp-Gln-Iva-Hyp-Aib-Pro-Phl(16). By using the uniformly (13)C,(15)N-labeled sample of Aam-I, the set of conformationally dependent J couplings and (3h)J(NC) couplings through H-bonds were measured.

Recombinant expression, synthesis, purification, and solution structure of arenicin.

Arenicins are 21-residue cationic antimicrobial peptides, isolated from marine polychaeta Arenicola marina. In order to determine a high-resolution three-dimensional structure of arenicin-2, the recombinant peptide was overexpressed as a fused form in Escherichia coli. Both arenicin isoforms were synthesized using the Fmoc-based solid-phase strategy.

Comparative study of structure and activity of cytotoxins from venom of the cobras Naja oxiana, Naja kaouthia, and Naja haje.

Cytotoxins are positively charged polypeptides that constitute about 60% of all proteins in cobra venom; they have a wide spectrum of biological activities. By CD spectroscopy, cytotoxins CT1 and CT2 Naja oxiana, CT3 Naja kaouthia, and CT1 and CT2 Naja haje were shown to have similar secondary structure in an aqueous environment, with dominating beta-sheet structure, and to vary in the twisting angle of the beta-sheet and the conformation of disulfide groups. Using dodecylphosphocholine micelles and liposomes, CT1 and CT2 Naja oxiana were shown to incorporate into lipid structures without changes in the secondary structure of the peptides.