Structural studies of canine parvovirus
Abstract
Canine Parvovirus (CPV) is a small single-stranded DNA virus with T = 1 icosahedral capsid arrangement. The structures of CPV full capsid and empty capsid have been determined to atomic resolution in the monoclinic and the tetragonal space groups, respectively. Diffraction data were collected mostly at Cornell High Energy Synchrotron Source (CHESS) and were processed by the Purdue film processing package. The long c axis (795.0A) of the tetragonal unit cell has posed difficulties in the data collection and data processing in the tetragonal space group. The phase determination of the CPV full particle structure was a combination of ab initio phasing from a spherical shell model and single isomorphous replacement phasing. The CPV empty capsid structure was solved by molecular replacement using the CPV full particle structure as a model. In both cases, the phase refinement and phase extension by molecular averaging were successful owing to the high redundancy of non-crystallographic symmetry and the accurate determination of particle orientation and position in the crystal unit cell. The position determination in the structure solution of the CPV full particles was facilitated by the icosahedrally bound heavy atom sites. The CPV empty capsid structure was refined to 3.0A resolution using the stereo-chemically restrained least-squares refinement program PROLSQ and the molecular dynamics refinement package X-PLOR. The R factor of the final atomic model is 21.2% with good geometry. The structure of CPV has given functional implications to many aspect of the virus life cycle including cellular attachment, uncoating, DNA packaging, assembly, antigenicity and hemagglutination properties. Most of the structural features of the refined CPV empty capsid structure are also true for the CPV full particle structure. The conformational difference between the CPV full and empty particle structures might provide insight to the specific DNA encapsidation and maturation process of CPV.
Degree
Ph.D.
Advisors
Rossmann, Purdue University.
Subject Area
Biochemistry|Molecular biology|Biophysics
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