tailieunhanh - Báo cáo khoa học: Structure and membrane interaction of the internal fusion peptide of avian sarcoma leukosis virus

The structure and membrane interaction of the internal fusion peptide (IFP) fragment of the avian sarcoma and leucosis virus (ASLV) envelope glycoprotein was studied by an array of biophysical methods. The peptide was found to induce lipidmixing of vesicles more strongly than the fusion peptide derived from the N-terminal fusion peptide of influenza virus (HA2-FP). It was observed that the helical structure was enhanced in association with the model membranes, particularly in the N-terminal portion of the to the infraredstudy, thepeptide inserted into themembrane in an oblique orientation, but less deeply than the influenza HA2-FP | Eur. J. Biochem. 271 4725-4736 2004 FEBS 2004 doi Structure and membrane interaction of the internal fusion peptide of avian sarcoma leukosis virus Shu-Fang Cheng Cheng-Wei Wu Eric Assen B Kantchev and Ding-Kwo Chang Institute of Chemistry Academia Sinica Taipei Taiwan Republic of China The structure and membrane interaction of the internal fusion peptide IFP fragment of the avian sarcoma and leucosis virus ASLV envelope glycoprotein was studied by an array of biophysical methods. The peptide was found to induce lipid mixing of vesicles more strongly than the fusion peptide derived from the N-terminal fusion peptide of influenza virus HA2-FP . It was observed that the helical structure was enhanced in association with the model membranes particularly in the N-terminal portion of the peptide. According to the infrared study the peptide inserted into the membrane in an oblique orientation but less deeply than the influenza HA2-FP. Analysis of NMR data in sodium dodecyl sulfate micelle suspension revealed that Pro13 of the peptide was located near the micelle-water interface. A type II b-turn was deduced from NMR data for the peptide in aqueous medium demonstrating a conformational flexibility of the IFP in analogy to the N-terminal FP such as that of gp41. A loose and multimodal self-assembly was deduced from the rhodamine fluorescence self-quenching experiments for the peptide bound to the membrane bilayer. Oligomerization of the peptide and its variants can also be observed in the electrophoretic experiments suggesting a property in common with other N-terminal FP of class I fusion proteins. Keywords membrane fusion conformational change insertion depth self-assembly fluorescence self-quenching. Entry of enveloped viruses into the host cells is mediated by the viral envelope glycoproteins 1 which in most cases are cleaved by proteolysis to yield the transmembrane TM 2 3 subunit responsible for membrane fusion and the surface SU .