5b56
From Proteopedia
Crystal structure of HIV-1 VPR C-Terminal domain and DIBB-M-Importin-Alpha2 complex
Structural highlights
FunctionIMA1_MOUSE Functions in nuclear protein import as an adapter protein for nuclear receptor KPNB1. Binds specifically and directly to substrates containing either a simple or bipartite NLS motif. Docking of the importin/substrate complex to the nuclear pore complex (NPC) is mediated by KPNB1 through binding to nucleoporin FxFG repeats and the complex is subsequently translocated through the pore by an energy requiring, Ran-dependent mechanism. At the nucleoplasmic side of the NPC, Ran binds to importin-beta and the three components separate and importin-alpha and -beta are re-exported from the nucleus to the cytoplasm where GTP hydrolysis releases Ran from importin. The directionality of nuclear import is thought to be conferred by an asymmetric distribution of the GTP- and GDP-bound forms of Ran between the cytoplasm and nucleus. Publication Abstract from PubMedViral protein R (Vpr) is an accessory gene product of human immunodeficiency virus type 1 (HIV-1) that plays multiple important roles associated with viral replication. Structural studies using NMR have revealed that Vpr consists of three alpha-helices and contains flexible N- and C-termini. However, the molecular mechanisms associated with Vpr function have not been elucidated. To investigate Vpr multifunctionality, we performed an X-ray crystallographic study of Vpr complexes containing importin-alpha, a known Vpr binding partner present in host cells. Elucidation of the crystal structure revealed that the flexible C-terminus changes its conformation to a twisted beta-turn via an induced-fit mechanism, enabling binding to a minor nuclear localization signal (NLS) site of importin-alpha. The Vpr C-terminus can also bind with major NLS sites of importin-alpha in an extended conformation in different ways. These results, which represent the first reported crystallographic analysis of Vpr, demonstrate the multifunctional aspects that enable Vpr interaction with a variety of cellular proteins. Molecular Mechanism of HIV-1 Vpr for Binding to Importin-alpha.,Miyatake H, Sanjoh A, Murakami T, Murakami H, Matsuda G, Hagiwara K, Yokoyama M, Sato H, Miyamoto Y, Dohmae N, Aida Y J Mol Biol. 2016 May 12. pii: S0022-2836(16)30140-1. doi:, 10.1016/j.jmb.2016.05.003. PMID:27181198[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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Categories: HIV-1 M:B 89 6 | Large Structures | Mus musculus | Aida Y | Dohmae N | Hagiwara K | Matusda G | Miyamoto Y | Miyatake H | Murakami H | Murakami T | Sanjoh A | Sato H | Yokoyama M
