Three-dimensional structures of the human α2-macroglobulin-methylamine and chymotrypsin complexes

The three-dimensional structures of chymotrypsin- and methylamine-treated negatively stained human α2-macroglobulin have been determined by weighted back projection from electron microscope data. Projections of the reconstructions show good concordance with two-dimensional averages of both stained and frozen-hydrated molecules. The reconstructions reveal that the H-shaped front projection of the molecule is related to the smaller ellipsoidal end...