Purification of E. coli 30S ribosomal proteins by high-performance liquid chromatography under non-denaturing conditions.

High-performance ion-exchange chromatography was applied to the separation of proteins from the 30S ribosomal subunit under non-denaturing conditions. It was shown that a single chromatographic step only allows the purification of nine proteins. To increase the number of separated proteins, a prefractionation step was added that depends on the physical characteristics of the proteins to be purified. Sixteen out of 21 proteins could be purified by using prefractionation (gel permeation and lithium chloride salt washing). This method is well suited to preparing fresh samples on demand for optical studies owing to the simplicity of the buffers used and the amounts of proteins recovered in the eluted peaks (0.05-0.1 mg/ml).