title: Lipid directed assembly of the HIV capsid protein.
abstract: Experimental evidence for in vivo capsid assembly suggests that capsid formation initiates from interactions between capsid (CA) proteins and lipids in the viral envelope. Various in vitro studies aiming to elucidate the detailed mechanisms of capsid self-assembly products have been carried out in conditions far removed from those, which would be encountered in a physiological environment. In this work we used lipid bilayers as a platform for studying the assembly of the CA protein with the rationale that the lipid-CA interactions play an important role in the nucleation of these structures. Observations using atomic force microscopy (AFM) have allowed a 'curling tadpole' mechanism to be suggested for the capsid self-assembly process. Stable dimeric CA proteins are able to move across the lipid bilayer to associate into trimers-of-dimers. These trimers form distinctly curved chains, which coil up to form larger features. As the feature grows additional trimers associate with the feature, giving a tadpole-like appearance. By comparing capsid assembly on mica, on single component lipid bilayers, and phase separated lipid bilayers, it was possible to determine the effect of lipid-protein interactions on capsid assembly.
authors.affiliation: Chemical Engineering and Advanced Materials, Newcastle University, Newcastle Upon Tyne, NE1 7RU, UK. d.j.frankel@newcastle.ac.uk.
authors.forename: Penny
authors.initials: P
authors.lastname: Miles
authors.forename: Daniel
authors.initials: D
authors.lastname: Frankel
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry / Q000378:metabolism; D000327:Adsorption; D000538:Aluminum Silicates / Q000737:chemistry; D002213:Capsid / Q000502:physiology*; D019281:Dimerization; D005997:Glycerylphosphorylcholine / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism; D016655:HIV Core Protein p24 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D015497:HIV-1 / Q000502:physiology*; D007700:Kinetics; D008051:Lipid Bilayers / Q000737:chemistry* / Q000378:metabolism; D018625:Microscopy, Atomic Force; D008954:Models, Biological; D010713:Phosphatidylcholines; D066329:Protein Aggregates; D017510:Protein Folding; D055550:Protein Stability; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D053835:Unilamellar Liposomes / Q000737:chemistry / Q000378:metabolism; D018406:Virus Physiological Phenomena
chemical_list: D000538:Aluminum Silicates; D016655:HIV Core Protein p24; D008051:Lipid Bilayers; D010713:Phosphatidylcholines; D066329:Protein Aggregates; D011994:Recombinant Proteins; D053835:Unilamellar Liposomes; D015060:1,2-Dipalmitoylphosphatidylcholine; D005997:Glycerylphosphorylcholine; C017251:1,2-oleoylphosphatidylcholine; C011934:mica