title: Crystallization and preliminary X-ray diffraction analysis of post-fusion six-helix bundle core structure from Newcastle disease virus F protein.
abstract: Fusion of virus members from the Paramyxoviridae family involves two glycoproteins. They are termed attachment glycoprotein (HN, H or G) and fusion protein (F). The F protein contains two highly conserved heptad-repeat (HR) regions, HR1 and HR2. Through conformational changes in the F protein, HR1 and HR2 are believed to form a stable six-helix coiled-coil bundle during the membrane-fusion process. However, no crystal structure has yet been documented for this state in the Newcastle disease virus (NDV, a member of the Paramyxoviridae family) F protein, despite the recent success on its F(0) crystal structure (Chen et al., 2001), which was thought to represent the pre-fusion conformation of F glycoprotein. In this study, a single-chain polypeptide constructed by linking two truncated HR regions of the NDV F protein has been expressed, purified and crystallized by means of the hanging- or sitting-drop vapour-diffusion method. Crystals in hexagonal and trapezoid forms with a resolution limit of 2.6 A were obtained. These crystals belonged to space group C2, with unit-cell parameters a = 66.4, b = 38.2, c = 102.0 A, beta = 100.2 degrees. Crystals in the rhombic form with a resolution limit of 2.5 A were also obtained. These crystals belonged to space group P2(1), with unit-cell parameters a = 59.0, b = 31.9, c = 62.3 A, beta = 117.0 degrees. This will add to the repertoire of viral fusion protein post-fusion state structures and help further the understanding of the molecular mechanism of enveloped virus fusion.
authors.affiliation: MOE Laboratory of Protein Sciences, School of Life Sciences and Bio-Engineering, Tsinghua University, Beijing 100084, People's Republic of China.
authors.forename: Peng-Yun
authors.initials: PY
authors.lastname: Li
authors.forename: Jie-Qing
authors.initials: JQ
authors.lastname: Zhu
authors.forename: Bei Li
authors.initials: BL
authors.lastname: Wu
authors.forename: Feng
authors.initials: F
authors.lastname: Gao
authors.forename: Po
authors.initials: P
authors.lastname: Tien
authors.forename: Zihe
authors.initials: Z
authors.lastname: Rao
authors.forename: George F
authors.initials: GF
authors.lastname: Gao
mesh_terms: D003460:Crystallization / Q000379:methods; D009522:Newcastle disease virus / Q000737:chemistry*; D011487:Protein Conformation; D020836:Protein Structure, Quaternary; D014760:Viral Fusion Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D014961:X-Ray Diffraction
chemical_list: D014760:Viral Fusion Proteins