Abstract
The ribosomal L30 proteins from strains of 27 species belonging to the genera Bacillus, Escherichia, Staphylococcus, Lactobacillus, Leuconostoc and Thermoactinomyces were analysed, together with AT-L30 proteins from selected actinomycetes. The results of partial amino acid sequencing of L30 preparations revealed that the members of the genera Escherichia, Staphylococcus and Thermoactinomyces were homogeneous within each genus. In contrast, phylogenetic diversity existed in the genus Bacillus, which contained at least four clusters. One cluster that contained Bacillus subtilis and Bacillus stearothermophilus was more closely related to the genus Staphylococcus than to members of the other three Bacillus clusters. Members of the genus Thermoactinomyces were most closely related to the 'Bacillus subtilis cluster', but less related to the other three Bacillus clusters. A distant phylogenetic relationship was detected between the genus Thermoactinomyces and its morphological relative, Thermomonospora.