Influenza A virus RNA polymerase PB2 subunit (PB2)

The **Influenza A virus RNA polymerase PB2 subunit** (PB2) is one component of the heterotrimeric RNA-dependent RNA polymerase complex, essential for viral replication and transcription. PB2, together with PB1 and PA subunits, forms the core enzyme responsible for copying and expressing the segmented negative-sense RNA genome of influenza A virus[1][2][3]. PB2 plays a critical role in cap-snatching: it binds the 5′ capped structures of host pre-mRNAs, which are then cleaved by the PA subunit and used by PB1 to prime viral mRNA synthesis[4]. Key residues in PB2, particularly lysine at position 627, are known to modulate host range and pathogenicity; mutations at this site affect both RNA binding activity and interspecies transmission[1]. Due to its essential enzymatic and structural roles, PB2 is a validated drug target for small-molecule inhibitors (notably cap-binding inhibitors such as VX-787)[4]. The protein is a primary determinant of replication efficiency and host adaptation, making it a focus for both antiviral drug development and virological surveillance.

Other names

Polymerase basic protein 2PB2 subunitInfluenza virus PB2Influenza A polymerase PB2

Inhibition of cap-binding activity, preventing cap-snatching and thus blocking viral transcription initiation Disruption of polymerase complex function, ultimately inhibiting viral RNA synthesis