Voltage‐dependent interaction of the peptaibol antibiotic zervamicin II with phospholipid vesicles

Abstract

The effect of a transmembrane potential on ion channel formation by zervamicin II (ZER-II) was studied in a vesicular model system. The dissipation of diffusion potential caused by addition of ZER-II to small phosphatidylcholine vesicles was monitored using fluorescent (Safranine T) and optical (Oxonol YI) probes. Cis-positive potentials facilitated channel formation, while at cis-negative potentials, ion fluxes were inhibited. A potential-independent behavior of ZER-II was observed at high peptide concentrations, most likely due to its membrane modifying property.z 1999 Federation of European Biochemical Societies.

Antiamoebin I in Methanol Solution: Rapid Exchange between Right‐Handed and Left‐Handed 310‐Helical Conformations

“…Antiamoebin I has the amino acid sequence: Ac-Phe 1 -Aib-Aib-Aib-Iva-Gly-Leu-Aib 8 -Aib-Hyp-Gln-Iva-Hyp-Aib-ProPhl 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. Analysis of these data along with the data on magnetic nonequivalence of the 13 …”

“…In model membrane systems, Zrv-IIB forms strongly voltage-dependent ionic channels with a characteristic set of dozen conductance levels [14] [15], while Aam-I in analogous systems displays voltage-independent leakage and weak voltage-dependent conductance on its top [16 -18]. Comparison of the peptaibol antimalarial activities indicated that antiamoebins are on average, by one order of magnitude less active than zervamicins, and display an IC 50 value of 5 mm [9].…”

Self‐aggregation properties of spin‐labeled zervamicin IIA as studied by PELDOR spectroscopy

“…The property of Zrv-TEMPO-16 to form ion channels was tested by means of the method that has been described before. 3 The analog shows the same activity as the native compound. …”

“…The product was shown to be pure (96%) by RP16 HPLC analysis. The chromatography has been carried out at a flow rate of 1 mL/min and by isocratic elution with 55% CH 3 OH/45% 0.01M NH 4 OAc for 5 min, followed by a gradient elution from 0 to 80% CH 3 OH/CH 3 Condensation of [des-Phl 16 ]-Zrv IIA with 4-amino-TEMPO (Sigma, USA) was performed by the racemizationfree HATU method in NMP and the product, Zrv-TEMPO-16, was isolated by the method described above. After gel filtration the peptide was purified by preparative reversed phase high performance liquid chromatography (RP-HPLC) using the column Diasorb-130-C16T (4 ϫ 250 mm) purchased from BioChimMak (Russia).…”

“…2,3 The crystal state has been studied by x-ray analysis. 4 More recently, the solution and micelle bound structures have been determined by high-resolution NMR spectroscopy.…”