Tandem repeat of the genes for protein S, a development-specific protein of Myxococcus xanthus

Protein S, a development-specific protein of Myxococcus xanthus is produced only during fruiting body formation. More than 15% of total protein synthesis during this period is accounted for by the production of protein S. The genes for protein S were identified and cloned with the use of mixed probes consisting of eight synthetic oligodeoxyribonucleotides (tetradecamers) which correspond to a carboxyl-terminal portion of protein S. The two genes are oriented in the same direction and are separated approximately 1.2 kilobases. The DNA sequences of the carboxyl-terminal portions of the two genes reveal that both can code for the identical eleven amino acid sequence which corresponds to the carboxyl-terminal end of protein S. However, there are a few base substitutions upstream of these regions. This duplication of genes in M. xanthus may facilitate the extremely rapid synthesis of protein S during fruiting body formation.