500-MHz 1H-NMR studies of ribosomal proteins isolated from 70-S ribosomes of Escherichia coli.

A method for the large-scale isolation of ribosomal proteins is described avoiding pre-separation of 30-S and 50-S subunits. Five proteins isolated in this way were studied with high-resolution 1H NMR at 500 MHz. These are S21, L18, L25, L30 and L33. The results show that L18, L25 and L30 exhibit tertiary structure in solution and indications for secondary structure in S21 are found. Protein L33 appears to be a random coil. Several resonances in the 1H NMR spectra are assigned to particular protons of amino acid residues, e.g. the aromatic ring protons of tyrosines and histidines, and epsilon-protons of lysines.