Structural Characterization of H-1 Parvovirus: Comparison of Infectious Virions to Empty Capsids

Abstract

bThe structure of single-stranded DNA (ssDNA) packaging H-1 parvovirus (H-1PV), which is being developed as an antitumor gene delivery vector, has been determined for wild-type (wt) virions and noninfectious (empty) capsids to 2.7-and 3.2-Å resolution, respectively, using X-ray crystallography. The capsid viral protein (VP) structure consists of an ␣-helix and an eightstranded anti-parallel ␤-barrel with large loop regions between the strands. The ␤-barrel and loops form the capsid core and surface, respectively. In the wt structure, 600 nucleotides are ordered in an interior DNA binding pocket of the capsid. This accounts for ϳ12% of the H-1PV genome. The wt structure is identical to the empty capsid structure, except for side chain conformation variations at the nucleotide binding pocket. Comparison of the H-1PV nucleotides to those observed in canine parvovirus and minute virus of mice, two members of the genus Parvovirus, showed both similarity in structure and analogous interactions. This observation suggests a functional role, such as in capsid stability and/or ssDNA genome recognition for encapsulation. The VP structure differs from those of other parvoviruses in surface loop regions that control receptor binding, tissue tropism, pathogenicity, and antibody recognition, including VP sequences reported to determine tumor cell tropism for oncotropic rodent parvoviruses. These structures of H-1PV provide insight into structural features that dictate capsid stabilization following genome packaging and three-dimensional information applicable for rational design of tumor-targeted recombinant gene delivery vectors. H -1 parvovirus (H-1PV) is a member of the rodent subgroup of the Parvovirus genus of the single-stranded DNA (ssDNA) Parvoviridae (1). H-1PV was first isolated from rats transplanted with HEP-1, a human liver adenocarcinoma cell line (2), and also from aborted human fetuses (3). Recombinant vectors based on H-1PV and a number of other rodent parvoviruses, including minute virus of mice (MVM) and LuIII, are promising candidates for antitumor delivery vectors, particularly for cytoreductive and immunogene therapy approaches (reviewed in references 4 and 5). The inherent oncotropism of these autonomous parvoviruses is based on their dependence on cellular proliferation factors expressed during the S phase and the differentiated state of the host cell (6, 7). The rodent parvoviruses display oncopreferential cytotoxic activity in vitro and also possess an oncosuppressive potential, inhibiting the formation of spontaneous and chemical or virus-induced tumors in vitro and in vivo (8-13). These viruses can also persistently infect their natural hosts, do not integrate their genome into cellular chromosomes, and are not associated with human disease (reviewed in reference 4).Recombinant rodent parvovirus vectors targeted for tumor therapy utilize a double-edged strategy that takes advantage of their inherent oncotropism and selective cytotoxicity plus their ability to deliver therapeutic genes that code for ...

Structure of neurotropic adeno-associated virus AAVrh.8

“…Further studies characterizing this VP-DNA interaction could aid efforts to improve vector packaging efficiency. However, this binding pocket is not conserved in the capsid structures of other parvoviruses that package only the negative sense strand of their genomes, and also the ordered NT observed in these structures is located in a different pocket (Agbandje-McKenna et al, 1998; Halder et al, 2013; Xie and Chapman, 1996). In addition, the NT observed in the AAVs constitutes a very small fraction (~1%) of the genome, and is lower than that observed for the autonomous parvoviruses (12–25%).…”

RETRACTED ARTICLE: VP2 capsid domain of the H-1 parvovirus determines susceptibility of human cancer cells to H-1 viral infection

“…Variable region 0 and 2 in H-1-VP2 capsid domain protrudes as compared with those seen on KRV VP2 domains A previous study reported the presence of nine variable region (VR)s in the H-1-VP2 protein, as compared with that of other parvoviruses, such as MVM, CPV, FPV and PPV, by crystal structure analysis. 8 Previous studies have also suggested that the VRs of VP2 protein from parvoviruses are involved in host cell interaction. 33,34 Based on these reports, we compared the VP2 structure between H-1 and KRV to explain the differential tropism, using SWISS modeling.…”

“…Modeling of VP2 capsid protein from KRV and H-1 virus A model of the KRV VP2 (GenBank accession no. 999997) protein was built with SWISS-MODEL, 26 using the H-1 parvovirus VP2 (PDB ID: 4G0R) 8 protein as a template. The template structure was selected based on amino-acid sequence identity (79% sequence identity) using the BLAST (basic local alignment search tool) search, and obtained from Protein Data Bank (http://www.rcsb.org) with the highest resolution.…”

Structure of an Enteric Pathogen, Bovine Parvovirus

“…To date, parvovirus VP VRs have been defined only for members within the same genus, namely, Protoparvovirus (VR0 to VR8) and Dependoparvovirus (VRI to VRIX), which have sequence identities in the range of 50 to 60 and 60 to 99%, respectively (50,60,61). The BPV structure increased the number of type member structures available for the Parvovirinae to five, enabling a subfamily-level definition of VRs.…”