Proteins of the <i>Thermus thermophilus</i> ribosome Purification of several individual proteins and crystallization of protein TL7

Abstract

The procedure of selective removal of eight proteins from the 50 S ribosomal subunit of the extreme thermophilic bacterium Thermus thermophilus has been developed based on extraction at 60°C in the presence of 0.5 M or 1 M NH 4 Cl and 50% ethanol. CM‐Sepharose CL column chromatography of the protein mixture under non‐denaturing conditions yielded five proteins with a purity of 95% or higher. Crystals of one of these proteins, namely TL7 (probably an analog of L6 protein from the Escherichia coli ribosome) have been obtained using the ‘hanging drop’ method with ammonium sulphate as a precipitant.