9TX7

Mature MPMV capsid hexamer 3-fold interface from capsid-like particles

Summary for 9TX7

• Entry DOI: 10.2210/pdb9tx7/pdb
• EMDB information: 56390
• Descriptor: Capsid protein p27 (1 entity in total)
• Functional Keywords: mpmv, m-pmv, capsid, mature, ca, p27, ip6, retrovirus, hexamer, capsomer, viral protein, 3-fold axis, c3
• Biological source: Mason-Pfizer monkey virus
• Total number of polymer chains: 6
• Total formula weight: 146028.11

Authors

Klarhof, J.O.,Stacey, J.C.V.,Briggs, J.A.G.,James, L.C. (deposition date: 2026-01-15, release date: 2026-10-07)

Primary citation

Klarhof, J.O.,Mallery, D.L.,Stacey, J.C.V.,Torre, D.,Rumlova, M.,Ruml, T.,Briggs, J.A.G.,James, L.C.
Retroviruses use different IP 6 binding mechanisms to alter the properties of their capsids.
Nat Commun, 17:-, 2026

PubMed Abstract: HIV-1 uses the metabolite inositol hexakisphosphate (IP) as a host factor to assemble its capsid, but whether this strategy is unique to lentiviruses or represents a common feature of retroviral capsids remains unclear. Here we show that IP binding is conserved across diverse retroviruses but occurs through distinct capsid sites and mechanisms, and influences viral behaviour. In contrast to HIV-1, the beta-retrovirus Mason-Pfizer Monkey Virus (MPMV) and the gamma-retrovirus Murine Leukaemia Virus (MLV) bind IP at the threefold lattice interface between capsomers rather than within capsomer pores. Cryo-EM structures of core-like particles reveal that two lysine residues from each capsomer coordinate IP between either two discrete three-lysine rings (MPMV) or a single heterogeneous six-lysine ring (MLV). MPMV and MLV are largely insensitive to IP availability in producer cells, but this binding mode renders them highly dependent on IP6 in target cells - the opposite of the dependency pattern of HIV-1. The way in which retroviruses use IP to build their capsids alters their dependence on the metabolite at different stages of the replicative cycle and in key capsid behaviours, such as assembly and stability.

PubMed: 42764334
DOI: 10.1038/s41467-026-76510-7

Experimental method

ELECTRON MICROSCOPY (4.1 Å)