9T1M

Nuclear export protein/Non-structural protein 2 (NEP/NS2) in complex with artificial alpha Rep protein

Summary for 9T1M

• Entry DOI: 10.2210/pdb9t1m/pdb
• Descriptor: Alpha Rep E4, Nuclear export protein (3 entities in total)
• Functional Keywords: nuclear export protein, non-structural protein 2, influenza virus, synthetic protein, viral protein
• Biological source: synthetic construct; More
• Total number of polymer chains: 4
• Total formula weight: 71053.89

Authors

Stelfox, A.J.,Ballandras-Colas, A.,Crepin, T. (deposition date: 2025-10-21, release date: 2025-11-12, Last modification date: 2025-11-19)

Primary citation

Stelfox, A.J.,Bessonne, M.,Bourhis, J.M.,Erba, E.B.,Albanese, P.,Compte, D.P.,Nevers, Q.,Urvoas, A.,Valerio-Lepiniec, M.,Minard, P.,Ruigrok, R.W.H.,Crepin, T.,Delmas, B.,Ballandras-Colas, A.
Monomeric Structure of Influenza A Virus NEP/NS2 Obtained With an Artificial Protein Highlights Conformational Plasticity.
J.Mol.Biol., 437:169511-169511, 2025

PubMed Abstract: The influenza virus nuclear export protein (NEP)/non-structural protein 2 (NS2) is a multifunctional protein, involved in viral ribonucleoprotein export from the nucleus, genome replication enhancement, and the adaption of avian influenza to mammals. Despite the growing attention on the importance of NEP in the influenza virus lifecycle and in interspecies transmission, the molecular details of how it performs its various roles are still not fully understood. For the purpose of assisting in structural characterization, a panel of artificial proteins (αReps) were selected against influenza virus A NEP by phage display. When complexed with E4, we were able to crystallize full-length NEP, and characterize the NEP-E4 interface using an integrative native MS-XL-MS strategy, revealing a folded and monomeric NEP conformation. The N- and C-termini of NEP pack together, with the middle linker region resembling a hinge, contrasting a previous structure where NEP is dimeric and elongated. Together these structures demonstrate the plasticity of NEP, a trait which may potentially aid NEP in binding cellular and viral partners. Using isothermal titration calorimetry (ITC) we measured a nanomolar interaction between E4 and NEP. Similarly, we found that E4 also binds NEP from human-isolated avian H7N9 and bovine-isolated avian H5N1 influenza viruses. Owing to their high degree of conservation, E4 likely has the capacity to interact with NEP from numerous influenza A virus strains. Indeed, this, combined with the nanomolar affinity measured between NEP/E4 could be explored further as a broad-range therapeutic strategy and/or a tool in cellulo to understand NEP function.

PubMed: 41175965
DOI: 10.1016/j.jmb.2025.169511

Experimental method

X-RAY DIFFRACTION (2.33 Å)