Purification of the elongation factor Tu (EF-Tu) from the cyanobacterium Spirulina platensis

Elongation factor Tu (EF-Tu) has been purified from the cyanobacterium Spirulina platensis. By gel electrophoresis the Mr of the purified protein appears to be 49 000, a value close to that reported for the EF-Tu isolated from a number of bacteria but higher than that reported for the protein isolated from Escherichia coli (43 000). Functionally, however, S. platensis EF-Tu may replace the E. coli protein in a protein-synthesizing system in vitro. In addition, its activity is affected by kirromycin, an antibiotic that specifically interacts with eubacterial EF-Tu.