title: Biophysical characterization of the feline immunodeficiency virus p24 capsid protein conformation and in vitro capsid assembly.
abstract: The Feline Immunodeficiency Virus (FIV) capsid protein p24 oligomerizes to form a closed capsid that protects the viral genome. Because of its crucial role in the virion, FIV p24 is an interesting target for the development of therapeutic strategies, although little is known about its structure and assembly. We defined and optimized a protocol to overexpress recombinant FIV capsid protein in a bacterial system. Circular dichroism and isothermal titration calorimetry experiments showed that the structure of the purified FIV p24 protein was comprised mainly of α-helices. Dynamic light scattering (DLS) and cross-linking experiments demonstrated that p24 was monomeric at low concentration and dimeric at high concentration. We developed a protocol for the in vitro assembly of the FIV capsid. As with HIV, an increased ionic strength resulted in FIV p24 assembly in vitro. Assembly appeared to be dependent on temperature, salt concentration, and protein concentration. The FIV p24 assembly kinetics was monitored by DLS. A limit end-point diameter suggested assembly into objects of definite shapes. This was confirmed by electron microscopy, where FIV p24 assembled into spherical particles. Comparison of FIV p24 with other retroviral capsid proteins showed that FIV assembly is particular and requires further specific study.
authors: Laboratoire de Biocristallographie et Biologie Structurale des Cibles Thérapeutiques, IBCP-BMSSI, UMR 5086 CNRS Université de Lyon, SFR BioSciences Gerland-Lyon Sud, Lyon, France.
authors: Jennifer
authors: J
authors: Serrière
authors: Daphna
authors: D
authors: Fenel
authors: Guy
authors: G
authors: Schoehn
authors: Patrice
authors: P
authors: Gouet
authors: Christophe
authors: C
authors: Guillon
mesh_terms: D055592:Biophysical Phenomena; D002213:Capsid / Q000187:drug effects / Q000378:metabolism*; D015683:Gene Products, gag / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D016089:Immunodeficiency Virus, Feline / Q000378:metabolism*; D011487:Protein Conformation / Q000187:drug effects; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D012492:Salts / Q000494:pharmacology; D013696:Temperature
chemical_list: D015683:Gene Products, gag; D011994:Recombinant Proteins; D012492:Salts; C074662:p24 protein, Feline immunodeficiency virus