Characterization of the First Marine Pestivirus, Phocoena Pestivirus (PhoPeV).

The first marine pestivirus, Phocoena pestivirus (PhoPeV), isolated from harbor porpoise, has been recently described. To further characterize this unique pestivirus, its host cell tropism and growth kinetics were determined in different cell lines. In addition, the interaction of PhoPeV with innate immunity in porcine epithelial cells and the role of selected cellular factors involved in the viral entry and RNA replication of PhoPeV were investigated in comparison to closely and distantly related pestiviruses.

Packaging defects in pestiviral NS4A can be compensated by mutations in NS2 and NS3.

The non-structural (NS) proteins of the members play a dual role in genome replication and virion morphogenesis. For pestiviruses, like bovine viral diarrhea virus, the NS2-3 region and its processing by the NS2 autoprotease is of particular importance. While uncleaved NS2-3 in complex with NS4A is essential for virion assembly, it cannot replace free NS3/4A in the viral replicase.

Characterization of a multipurpose NS3 surface patch coordinating HCV replicase assembly and virion morphogenesis.

The hepatitis C virus (HCV) life cycle is highly regulated and characterized by a step-wise succession of interactions between viral and host cell proteins resulting in the assembly of macromolecular complexes, which catalyse genome replication and/or virus production. Non-structural (NS) protein 3, comprising a protease and a helicase domain, is involved in orchestrating these processes by undergoing protein interactions in a temporal fashion. Recently, we identified a multifunctional NS3 protease surface patch promoting pivotal protein-protein interactions required for early steps of the HCV life cycle, including NS3-mediated NS2 protease activation and interactions required for replicase assembly.

DNAJC14-Independent Replication of the Atypical Porcine Pestivirus.

Atypical porcine pestiviruses (APPV; ) are a recently discovered, very divergent species of the genus within the family . The presence of APPV in piglet-producing farms is associated with the occurrence of so-called "shaking piglets," suffering from mild to severe congenital tremor type A-II. Previous studies showed that the cellular protein DNAJC14 is an essential cofactor of the NS2 autoprotease of all classical pestiviruses.

NMR Experiments Provide Insights into Ligand-Binding to the SARS-CoV-2 Spike Protein Receptor-Binding Domain.

We have used chemical shift perturbation (CSP) and saturation transfer difference (STD) NMR experiments to identify and characterize the binding of selected ligands to the receptor-binding domain (RBD) of the spike glycoprotein (S-protein) of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We also subjected full-length S-protein to STD NMR experiments, allowing correlations with RBD-based results. CSPs reveal the binding sites for heparin and fondaparinux, and affinities were measured using CSP titrations.