An improved method for two-dimensional gel-electrophoresis: analysis of mutationally altered ribosomal proteins of Escherichia coli.

An improved method for the two-dimensional electrophoretic analysis of ribosomal proteins on acrylamide gel slabs has been developed by combining the procedures for the first dimension of Mets and Bogorad (1974) and for the second dimension of Kaltschmidt and Wittmann (1970) and by introducing several modifications. Ribosomal proteins of various Escherichia coli mutants have been analyzed by the new method. Advantages are that (1) it requires only small amounts of protein (100-200 micrograms 70S ribosomal proteins), (2) reproducibility is very high, and (3) it makes it easier to identify mutational alterations in proteins S10, L4, L10, and L21 which hardly migrate out of the sample gel with our previous electrophoresis procedure. Furthermore, the new method can be nicely adapted to analysis of the ribosomal proteins from other organisms, such as Bacilli or yeast.