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Publication Abstract from PubMed

Bovine Parvovirus (BPV), the causative agent of respiratory and gastrointestinal disease in cows, is the type member of the Bocaparvovirus genus of the Parvoviridae. Towards efforts to obtain a template for the development of vaccines and small molecule inhibitors for this pathogen, the structure of the BPV capsid, assembled from the major capsid viral protein 2 (VP2), was determined using X-ray crystallography and cryo-electron microscopy and three-dimensional image reconstruction to 3.2 and 8.8 A resolution, respectively. The VP2 region ordered in the crystal structure, residues 39-536, conserves the parvoviral eight-stranded jellyroll motif and an alphaA helix. The BPV capsid displays common parvovirus features: a channel at and depressions surrounding the 5-fold axes, and protrusions surrounding the 3-fold axes. However, rather than a depression centered at the 2-fold axes, a raised surface loop divides this feature in BPV. Additional observed density in the capsid interior in the cryo-reconstructed map, compared to the crystal structure, is interpreted as ten additional N-terminal residues, 29-38 that radially extends the channel under the 5-fold axis, as observed for Human Bocavirus 1. Surface loops of varying lengths and conformations extend from the core jellyroll motif of VP2. These confer the unique surface topology of the BPV capsid, making it strikingly different from HBoV1 as well as the type members of other Parvovirinae genera for which structures have been determined. For the type members, structurally analogous regions to those decorating the BPV capsid surface serve as determinants of receptor recognition, tissue and host tropism, pathogenicity, and antigenicity. IMPORTANCE: Bovine parvovirus (BPV), identified in the 1960s in diarrheic calves, is a type member of the Bocaparvovirus genus of the non-enveloped, ssDNA Parvoviridae family. Recent isolation of human bocaparvoviruses from children with severe respiratory and gastrointestinal infections has generated interest in understanding the lifecycle and pathogenesis of these emerging viruses. We have determined high-resolution structure of the BPV capsid assembled from its predominant capsid protein VP2, known to be involved in a myriad of functions during host cell entry, pathogenesis, and antigenicity for other Parvovirinae members. Our results indicate the conservation of the core secondary structural elements and the location of the N-terminal residues for the known bocaparvovirus capsid structures. However, surface loops with high variability in sequence and conformation give BPV a unique capsid surface topology. Similar analogous regions in other Parvovirinae type members are important as determinants of receptor recognition, tissue and host tropism, pathogenicity, and antigenicity.

Structure of an Enteric Pathogen Bovine Parvovirus.,Kailasan S, Halder S, Gurda B, Bladek H, Chipman PR, McKenna R, Brown K, Agbandje-McKenna M J Virol. 2014 Dec 17. pii: JVI.03157-14. PMID:25520501^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.