title: Estimation of variance distribution in three-dimensional reconstruction. II. Applications.
abstract: A previously developed theory of three-dimensional (3-D) variance estimation [J. Opt. Soc. Am. A 12, 2615-2627 (1995)] is applied to the structural study of a hemocyanin-Fab complex with the electron microscope. The precise locations of structurally variable regions of the macromolecule are determined from the 3-D variance maps. The structural differences among different classes of the macromolecular complex are assessed by the use of the statistical t-test, and the 3-D antibody binding sites are revealed. From a model analysis, a rule is demonstrated for visually identifying a 3-D conformational change by the inspection of the 3-D variance map. Our analysis lays the foundation for numerous practical applications of variance estimation in the 3-D imaging of macromolecules.
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D000936:Antigen-Antibody Complex / Q000648:ultrastructure*; D001666:Binding Sites, Antibody; D000939:Epitopes; D006433:Hemocyanins / Q000648:ultrastructure*; D006737:Horseshoe Crabs; D007140:Immunoglobulin Fab Fragments / Q000648:ultrastructure*; D008854:Microscopy, Electron; D008961:Models, Structural; D008962:Models, Theoretical; D008968:Molecular Conformation
chemical_list: D000936:Antigen-Antibody Complex; D000939:Epitopes; D007140:Immunoglobulin Fab Fragments; D006433:Hemocyanins