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Publication Abstract from PubMed

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-mus time scale. Extensive ms-mus 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 mus-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.

Peptaibol antiamoebin I: spatial structure, backbone dynamics, interaction with bicelles and lipid-protein nanodiscs, and pore formation in context of barrel-stave model.,Shenkarev ZO, Paramonov AS, Lyukmanova EN, Gizatullina AK, Zhuravleva AV, Tagaev AA, Yakimenko ZA, Telezhinskaya IN, Kirpichnikov MP, Ovchinnikova TV, Arseniev AS Chem Biodivers. 2013 May;10(5):838-63. doi: 10.1002/cbdv.201200421. PMID:23681729^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.