title: Molecular analysis and solution structure from small-angle X-ray scattering of the human natural killer inhibitory receptor IRp60 (CD300a).
abstract: Natural killer (NK) cells are lymphocytes of the innate immune system specialized in recognition and killing of certain virus-infected and tumor cells. To carry out this task, NK cells are equipped with a complex array of germ line encoded receptors. These receptors deliver either positive or negative signals, and a delicate balance between these signals governs the NK cell cytolytic activity against the target cell. IRp60 (CD300a) is a human NK inhibitory receptor with an immunoglobulin-like fold. In the present study the IRp60 protein was expressed in Escherichia coli as inclusion bodies and refolded by dilution. The refolded protein was purified to homogeneity, biochemical characterized and the solution structure was investigated using small-angle X-ray scattering (SAXS). The SAXS data revealed that IRp60 is monomeric in solution with a molecular shape characteristic of the immunoglobulin-like structures. A homology model of IRp60 was built and validated experimentally against the SAXS data.
authors.affiliation: Laboratorio di Medicina Molecolare, Istituto Giannina Gaslini, Largo Gerolamo Gaslini 5, 16147 Genova, Italy. ndimasi@gmail.com
authors.forename: Nazzareno
authors.initials: N
authors.lastname: Dimasi
authors.forename: Manfred
authors.initials: M
authors.lastname: Roessle
authors.forename: Oscar
authors.initials: O
authors.lastname: Moran
authors.forename: Giovanni
authors.initials: G
authors.lastname: Candiano
authors.forename: Dmitri I
authors.initials: DI
authors.lastname: Svergun
authors.forename: Roberto
authors.initials: R
authors.lastname: Biassoni
mesh_terms: D015703:Antigens, CD; D006801:Humans; D007694:Killer Cells, Natural / Q000737:chemistry* / Q000276:immunology; D009369:Neoplasms / Q000276:immunology; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D011971:Receptors, Immunologic / Q000737:chemistry* / Q000276:immunology; D054340:Receptors, KIR; D011994:Recombinant Proteins / Q000737:chemistry / Q000276:immunology; D014777:Virus Diseases / Q000276:immunology
chemical_list: D015703:Antigens, CD; C515070:CD300A protein, human; D011971:Receptors, Immunologic; D054340:Receptors, KIR; D011994:Recombinant Proteins