title: Global structure of HIV-1 neutralizing antibody IgG1 b12 is asymmetric.
abstract: Human antibody IgG1 b12 is one of the four antibodies known to neutralize a broad range of human immunodeficiency virus-1. The crystal structure of this antibody displayed an asymmetric disposition of the Fab arms relative to its Fc portion. Comparison of structures solved for other IgG1 antibodies led to a notion that crystal packing forces entrapped a "snap-shot" of different conformations accessible to this antibody. To elucidate global structure of this unique antibody, we acquired small-angle X-ray scattering data from its dilute solution. Data analysis indicated that b12 adopts a bilobal globular structure in solution with a radius of gyration and a maximum linear dimension of approximately 54 and approximately 180A, respectively. Extreme similarity between its solution and crystal structure concludes that non-flexible, asymmetric shape is an inherent property of this rare antibody.
authors.affiliation: Institute of Microbial Technology, Sector 39-A, Chandigarh 160036, India. ashgang@imtech.res.in
authors.lastname: Ashish
authors.forename: Ashish K
authors.initials: AK
authors.lastname: Solanki
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Boone
authors.forename: Joanna K
authors.initials: JK
authors.lastname: Krueger
mesh_terms: D057134:Antibodies, Neutralizing / Q000737:chemistry*; D018360:Crystallography, X-Ray; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000737:chemistry*; D011487:Protein Conformation; D053838:Scattering, Small Angle; D014961:X-Ray Diffraction
chemical_list: D057134:Antibodies, Neutralizing; D007074:Immunoglobulin G