8RN2

Monomeric apo-influenza B polymerase, encapsidase conformation

Summary for 8RN2

• Entry DOI: 10.2210/pdb8rn2/pdb
• EMDB information: 19384
• Descriptor: Polymerase acidic protein, RNA-directed RNA polymerase catalytic subunit, Polymerase basic protein 2 (3 entities in total)
• Functional Keywords: viral polymerase, viral protein
• Biological source: Influenza B virus (B/Memphis/13/2003); More
• Total number of polymer chains: 3
• Total formula weight: 258536.61

Authors

Arragain, B.,Cusack, S. (deposition date: 2024-01-09, release date: 2024-09-11)

Primary citation

Arragain, B.,Krischuns, T.,Pelosse, M.,Drncova, P.,Blackledge, M.,Naffakh, N.,Cusack, S.
Structures of influenza A and B replication complexes give insight into avian to human host adaptation and reveal a role of ANP32 as an electrostatic chaperone for the apo-polymerase.
Nat Commun, 15:6910-6910, 2024

PubMed Abstract: Replication of influenza viral RNA depends on at least two viral polymerases, a parental replicase and an encapsidase, and cellular factor ANP32. ANP32 comprises an LRR domain and a long C-terminal low complexity acidic region (LCAR). Here we present evidence suggesting that ANP32 is recruited to the replication complex as an electrostatic chaperone that stabilises the encapsidase moiety within apo-polymerase symmetric dimers that are distinct for influenza A and B polymerases. The ANP32 bound encapsidase, then forms the asymmetric replication complex with the replicase, which is embedded in a parental ribonucleoprotein particle (RNP). Cryo-EM structures reveal the architecture of the influenza A and B replication complexes and the likely trajectory of the nascent RNA product into the encapsidase. The cryo-EM map of the FluB replication complex shows extra density attributable to the ANP32 LCAR wrapping around and stabilising the apo-encapsidase conformation. These structures give new insight into the various mutations that adapt avian strain polymerases to use the distinct ANP32 in mammalian cells.

PubMed: 39160148
DOI: 10.1038/s41467-024-51007-3

Experimental method

ELECTRON MICROSCOPY (2.89 Å)