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Canine parvovirus capsid structure, analyzed at 2.9 A resolution
1Department of Chemistry, Florida State University, Tallahassee 32306-3015, USA.
Journal of Molecular Biology
|December 6, 1996
Summary
Atomic refinement of canine parvovirus (CPV) reveals unique N-terminal capsid protein configurations and extensive secondary structures. These findings explain antigenic variations and provide insights into the virus
Area of Science:
- Structural biology
- Virology
- Biochemistry
Background:
- Canine parvovirus (CPV) capsid structure and assembly are crucial for its infectivity.
- Previous models of CPV capsid structure had limitations in explaining antigenic variability and assembly dynamics.
Purpose of the Study:
- To perform atomic refinement of the CPV capsid structure at 2.9 A resolution.
- To elucidate the N-terminal protein configurations and secondary structure elements.
- To understand the mechanisms of capsid assembly and DNA packaging.
Main Methods:
- Atomic refinement of the CPV capsid structure.
- Analysis of electron density and potential hydrogen bonds.
- Estimation of free energies of association for subunit interactions.
Main Results:
- Detailed atomic model of the CPV capsid, revealing N-terminal extensions through pores in ~13% of subunits.
- Identification of extensive secondary structures, particularly in loop insertions, contributing to specific assembly interactions.
- Evidence for a multi-step assembly process with loop intertwining and a preference for 3- and 5-fold contacts.
Conclusions:
- The N-terminal variations explain conflicting antigenic data and influence capsid assembly.
- The identified secondary structures enhance subunit interactions and specificity.
- Capsid assembly is a complex process, with loop intertwining creating a significant barrier to dissociation.
- DNA packaging relies on uncharged polar and van der Waals interactions rather than basic amino acids.