Influenza viruses are major human pathogens which cause annual epidemics (type A, B and C viruses) and have zoonotic and pandemic potential (type A viruses). The viral RNA dependent RNA polymerase (FluPol) is a key determinant of viral host-range and pathogenicity, and a prime target for antiviral drugs. It is a ~260 kDa heterotrimer composed of the subunits PB1 (polymerase basic protein 1), PB2 (polymerase basic protein 2) and PA (polymerase acidic protein). In viral particles each of the eight negative-sense RNA genomic segments (vRNAs) is associated with one copy of the viral polymerase and encapsidated with multiple copies of the nucleoprotein (NP) to form viral ribonucleoproteins (vRNPs). Upon viral infection, incoming vRNPs are imported into the nucleus in which FluPol performs transcription and replication of the viral genome through distinct primed and unprimed mechanisms. FluPol associates dynamically with many cellular proteins, among which the interaction with the host RNAP II transcription machinery. The FluPol CTD-binding interface is essential not only for transcription but also for replication of the viral genome. Here you can see a cryoEM structure of the Influenza A/H7N9 polymerase symmetric dimer bound to a promoter sequence (PDB code: 8POH)

#molecularart ... #influenza .. #polymerase ... #dimer ... #promoter ... #cryoem

Structure rendered with @proteinimaging and depicted with @corelphotopaint