5kp9
From Proteopedia
Structure of Nanoparticle Released from Enveloped Protein Nanoparticle
Structural highlights
FunctionGAG_HV1B1 Gag polyprotein: Mediates, with Gag-Pol polyrotein, the essential events in virion assembly, including binding the plasma membrane, making the protein-protein interactions necessary to create spherical particles, recruiting the viral Env proteins, and packaging the genomic RNA via direct interactions with the RNA packaging sequence (Psi).[UniProtKB:P04591] Matrix protein p17: Targets the polyprotein to the plasma membrane via a multipartite membrane-binding signal, that includes its myristoylated N-terminus (By similarity). Matrix protein is part of the pre-integration complex. Implicated in the release from host cell mediated by Vpu. Binds to RNA (By similarity).[UniProtKB:P12493] Capsid protein p24: Forms the conical core that encapsulates the genomic RNA-nucleocapsid complex in the virion. Most core are conical, with only 7% tubular. The core is constituted by capsid protein hexamer subunits. The core is disassembled soon after virion entry (By similarity). Host restriction factors such as TRIM5-alpha or TRIMCyp bind retroviral capsids and cause premature capsid disassembly, leading to blocks in reverse transcription. Capsid restriction by TRIM5 is one of the factors which restricts HIV-1 to the human species. Host PIN1 apparently facilitates the virion uncoating (By similarity). On the other hand, interactions with PDZD8 or CYPA stabilize the capsid (By similarity).[UniProtKB:P04591][UniProtKB:P12493] Nucleocapsid protein p7: Encapsulates and protects viral dimeric unspliced genomic RNA (gRNA). Binds these RNAs through its zinc fingers. Acts as a nucleic acid chaperone which is involved in rearangement of nucleic acid secondary structure during gRNA retrotranscription. Also facilitates template switch leading to recombination. As part of the polyprotein, participates to gRNA dimerization, packaging, tRNA incorporation and virion assembly.[UniProtKB:P04591] p6-gag: Plays a role in budding of the assembled particle by interacting with the host class E VPS proteins TSG101 and PDCD6IP/AIP1.[UniProtKB:P12493]Q9WXS1_THEMA Publication Abstract from PubMedComplex biological processes are often performed by self-organizing nanostructures comprising multiple classes of macromolecules, such as ribosomes (proteins and RNA) or enveloped viruses (proteins, nucleic acids and lipids). Approaches have been developed for designing self-assembling structures consisting of either nucleic acids or proteins, but strategies for engineering hybrid biological materials are only beginning to emerge. Here we describe the design of self-assembling protein nanocages that direct their own release from human cells inside small vesicles in a manner that resembles some viruses. We refer to these hybrid biomaterials as 'enveloped protein nanocages' (EPNs). Robust EPN biogenesis requires protein sequence elements that encode three distinct functions: membrane binding, self-assembly, and recruitment of the endosomal sorting complexes required for transport (ESCRT) machinery. A variety of synthetic proteins with these functional elements induce EPN biogenesis, highlighting the modularity and generality of the design strategy. Biochemical analyses and cryo-electron microscopy reveal that one design, EPN-01, comprises small (~100 nm) vesicles containing multiple protein nanocages that closely match the structure of the designed 60-subunit self-assembling scaffold. EPNs that incorporate the vesicular stomatitis viral glycoprotein can fuse with target cells and deliver their contents, thereby transferring cargoes from one cell to another. These results show how proteins can be programmed to direct the formation of hybrid biological materials that perform complex tasks, and establish EPNs as a class of designed, modular, genetically-encoded nanomaterials that can transfer molecules between cells. Designed proteins induce the formation of nanocage-containing extracellular vesicles.,Votteler J, Ogohara C, Yi S, Hsia Y, Nattermann U, Belnap DM, King NP, Sundquist WI Nature. 2016 Dec 8;540(7632):292-295. doi: 10.1038/nature20607. Epub 2016 Nov 30. PMID:27919066[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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