Release of certain ribosomal proteins from 70-S Escherichia coli ribosomes by mild ribonuclease digestion

Abstract

A method for the release of some proteins from Escherichia coli (MRE 600)ribosomes is described, avoiding extraction with denaturing reagents. High-salt-washed, 70-S ribosomes were treated with pancreatic ribonuclease which led to the release of 12 proteins of the larger ribosomal subunit. Separation of released protein was first attempted by gel filtration and by fractionation with (NH4)2SO4. The number and type of the released proteins were identified by sodium dodecyl sulphate-polyacrylamide gels and two-dimensional gel electrophoresis. The method should prove of use in the large scale purification of proteins L1, L7, and L25.