NMR Characterization of the Fusogenic Conformation of the Fusion Peptide of Vesicular Stomatitis Virus
Sarzedas, C.G.1, Lima, C. S.2, Da Poian, A. T. 2, Valente, A.P. 1 and Almeida, F.C.L. 1
1 Centro Nacional de Ressonância Magnética Nuclear Jiri Jonas, Instituto de Bioquímica Médica, UFRJ, Rio de Janeiro-RJ, 21.941-590, 2 Instituto de Bioquímica Médica, UFRJ, Rio de Janeiro-RJ, 21.941-590.
Vesicular Stomatitis Virus (VSV) is a member of the generus Vesiculovirus, Rhabdoviridae family and is pathogenic to horses, cattle, pigs and others animals. The infection by VSV begins when glicoprotein G (a transmembrane protein) interacts with the membrane of target cells. Conformational changes in glicoprotein G that happens at acidic pH promote the entrance of the virus in the cell. The region between residues 145-164 residues mimetizes the fusion properties of the entire glicoprotein and is called “fusion peptide” (pVSV). The reorganization of glicoprotein G is necessary to induce the fusion, and happens between pH 5.8 and pH 6.2. Modification of histidine residue inhibited membrane fusion mediates by the VSV.
In the present work we show the structural determination of pVSV by NMR in the presence of SDS micelles at pH 7.5 and pH 6.0. There are two helical regions, one in N-terminal region (150-155) and another in C-terminal region (160-163). Chemical shift data of pVSV free in aqueous solution shows fast helix-random coil equilibrium, with tendency to helix in the N- and C-terminal. Chemical shift analysis of pVSV in SDS micelles shows that the N-terminal helix undegoes a complex equilibrium between helix-random coil and extended structure. This equilibrium was studied in the presence of PC:PS vesicles and was observed that the N-terminal helix displays fast helix-coil equilibrium at non fusogenic state while at pH 6.0 (fusogenic state), in the presence of vesicles, the N-terminal helix shows fast equilibrium between helix-coil-extended structure. In the presence of PC:PS vesicles became evident that the transition to the fusogenic state involves the formation of extended structure at N-terminal region. Acknowledgements: CNPq, FAPERJ, PRONEX, ICGEB.
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