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

Abstract

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 49000, 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 (43000). 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.

Two tuf genes in the cyanobacterium Spirulina platensis

“…The homology between the tuf genes in E. coli and S. platensis is not unexpected since the gene product, purified from E. coli and S. platensis, EF-Tu, are similar proteins, functionally interchangeable in in vitro assays (19). In preliminary experiments in which plasmid pSpl25 containing the putative tuf genes was transcribed and translated in vitro in an E. coli system, a radioactive band was found with the same mobility of authentic S. platensis EF-Tu.…”

Purification of elongation factor Tu (EF-Tu) from sulfur-dependent and methanogenic archaebacteria

“…Fractions having the highest activity were pooled and proteins therein were precipitated with 70% saturated (NH4)2SO 4. The resultant pellet was dissolved in 1.0 ml of Buffer A and EF-Tu was purified by affinity chromatography on GDP-AH-Sepharose as detailed in [16] and [17]. Spirulina platensis and plant chloroplast EF-Tu factors were purified as described previously [2,17].…”

“…2), (5-9) fractions eluted from the GDP-Sepharose colunm with GDP-containing Buffer A. (B) The preparation from the G-100 Sephadex column was absorbed onto GDP-Sepharose and treated as reported in[17]. Ten-ml fractious were collected for the first 100 ml (fractions 1-10), and 1,5 ml fractions when the GDP-containing Buffer A was passed through the column (fractions 0-5); (O O), [3H]GDP binding activity determined on 5-/~1 aliquots of the effluent fractions; (r, zx), absorbance at 280 nm.205…”