Preparation of Ribosomal Proteins

Three major methods have been employed for the isolation of all E. coli ribosomal proteins. 

After dissociation of the 70 S ribosome into its two subunits followed by zonal centrifugation for the separation and isolation of the 30 S and 50 S subunits on a preparative scale, the ribosomal proteins were extracted by acetic acid and then separated by cellulose ion exchange chromatography and by gel filtration on Sephadex in the presence of 6 M urea. In this way all the 53 individual ribosomal proteins have been isolated (Wittmann, 1974). Proteins prepared in this manner have been used for physical studies (Brimacombe et al., 1978 Wittmann, 1982) as well as for immunological investigations (Stoffler et al., 1980 Lake, 

1980) and protein-sequence analyses (Wittmann et ai, 1980 Wittmann-Liebold, 1980b). 

After isolation in a pure state, each of the ribosomal proteins was injected into rabbits and/or sheep, and antibodies were obtained. It was demonstrated by various immunological techniques that there is no significant immunological cross-reaction among any of the E. coti ribosomal 

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