Shape of protein L11 from the 50S ribosomal subunit of Escherichia coli

Abstract

Protein L11 from the 50S ribosomal subunit of Escherichia coli A19 was purified by a method using nondenaturing conditions. Its shape in solution was studied by hydrodynamic and low-angle x-ray scattering experiments. The results from both methods are in good agreement. In buffers similar to the ribosomal reconstitution buffer, the protein is monomeric at concentrations up to 3 mg/mL and has a molecular weight of 16 000-17 000. The protein molecule resembles a prolate ellipsoid with an axial ratio of 5-6:1 a radius of gyration of 34 A, and a maximal length of 150 A. From the low-angle x-ray diffraction data, a more refined model of the protein molecule has been constructed consisting of two ellipsoids joined by their long axes.