Ribulose Bisphosphate Carboxylase: A Two-Layered Square-Shaped Molecule of Symmetry 422

摘要

Electron micrographs and x-ray diffraction patterns of crystals of ribu-lose bisphosphate carboxylase, probably the most abundant protein on earth, have provided new details of the arrangement of subunits. The eight large subunits and eight small subunits are clustered in two layers, perpendicular to a fourfold axis of symmetry. Viewed down thefowfold axis, the molecule is square-shaped.