Peptaibol antiamoebin I: spatial structure, backbone dynamics, interaction with bicelles and lipid-protein nanodiscs, and pore formation in context of barrel-stave model.Shenkarev, Z.O., Paramonov, A.S., Lyukmanova, E.N., Gizatullina, A.K., Zhuravleva, A.V., Tagaev, A.A., Yakimenko, Z.A., Telezhinskaya, I.N., Kirpichnikov, M.P., Ovchinnikova, T.V., Arseniev, A.S.
(2013) Chem.Biodivers. 10: 838-863
- PubMed: 23681729
- DOI: 10.1002/cbdv.201200421
- PubMed Abstract:
Antiamoebin I (Aam-I) is a membrane-active peptaibol antibiotic isolated from fungal species belonging to the genera Cephalosporium, Emericellopsis, Gliocladium, and Stilbella. In comparison with other 16-amino acid-residue peptaibols, e.g., zervamic ...
Antiamoebin I (Aam-I) is a membrane-active peptaibol antibiotic isolated from fungal species belonging to the genera Cephalosporium, Emericellopsis, Gliocladium, and Stilbella. In comparison with other 16-amino acid-residue peptaibols, e.g., zervamicin IIB (Zrv-IIB), Aam-I possesses relatively weak biological and channel-forming activities. In MeOH solution, Aam-I demonstrates fast cooperative transitions between right-handed and left-handed helical conformation of the N-terminal (1-8) region. We studied Aam-I spatial structure and backbone dynamics in the membrane-mimicking environment (DMPC/DHPC bicelles)(1) ) by heteronuclear (1) H,(13) C,(15) N-NMR spectroscopy. Interaction with the bicelles stabilizes the Aam-I right-handed helical conformation retaining significant intramolecular mobility on the ms-μs time scale. Extensive ms-μs dynamics were also detected in the DPC and DHPC micelles and DOPG nanodiscs. In contrast, Zrv-IIB in the DPC micelles demonstrates appreciably lesser mobility on the μs-ms time scale. Titration with Mn(2+) and 16-doxylstearate paramagnetic probes revealed Aam-I binding to the bicelle surface with the N-terminus slightly immersed into hydrocarbon region. Fluctuations of the Aam-I helix between surface-bound and transmembrane (TM) state were observed in the nanodisc membranes formed from the short-chain (diC12 : 0) DLPC/DLPG lipids. All the obtained experimental data are in agreement with the barrel-stave model of TM pore formation, similarly to the mechanism proposed for Zrv-IIB and other peptaibols. The observed extensive intramolecular dynamics explains the relatively low activity of Aam-I.
Shemyakin & Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya str., 16/10, 117997 Moscow, Russia. firstname.lastname@example.org