title: Hemocyanins in spiders, XVI[1]. Subunit topography and a model of the quaternary structure of Eurypelma hemocyanin.
abstract: Specific antibodies were prepared against the individual subunits of the hemocyanin isolated from the tarantula Eurypelma californicum. From the antibodies, the monovalent antigen-binding fragments (Fab) were made by papain treatment. Native 37S hemocyanin was incubated with individual Fab species and the labelling of the seven subunits (a, b, c, d, e, f and g) analyzed by electron microscopy. Specific labelling patterns were found for each Fab, which allowed the allocation of specific positions to each subunit within the (4 x 6)-subunit oligomer. Along the large cleft which separates the two dodecameric half-molecules, subunits f, b, c, f are located; e forms the four corners of the 37S particle, while a is found on both sides of the small cleft which separates the two hexamers within each dodecamer, d is close to a on the outer long edges, and g close to f at the side of the particle. These results and those obtained previously by means of partial dissociation and reassembly experiments, confirm and support each other, allowing the construction of a model of the quaternary structure of Eurypelma hemocyanin.
mesh_terms: D000818:Animals; D006433:Hemocyanins / Q000032:analysis*; D007123:Immunoelectrophoresis, Two-Dimensional; D008854:Microscopy, Electron; D010446:Peptide Fragments / Q000032:analysis; D013112:Spiders / Q000032:analysis*
chemical_list: D010446:Peptide Fragments; D006433:Hemocyanins