Isolation and Characterization of Streptomyces aureofaciens Protein‐Synthesis Elongation Factor Tu in an Aggregated State

Abstract

The ability of EF‐Tu to aggregate spontaneously was employed for the purification of homogeneous EF‐Tu · GDP from Streptomyces aureofaciens. The formation of filamentous structures in the aggregated EF‐Tu was demonstrated in a light microscope. The purified factor, with a specific activity of 19 100 ± 1000 units/mg in [3H]GDP exchange, was shown to be active in the translation of poly(U). Aggregated EF‐Tu · GDP exhibited almost eight‐times lower GDP‐exchange capacity at 2°C than at 30°C. This suggests that GDP‐binding sites are not freely accessible at lower temperatures in the aggregated factor, in contrast to Escherichia coli polymerized EF‐Tu. Turbidimetric assays revealed that the solubilization of diluted aggregated S. aureofaciens EF‐Tu is strongly dependent on temperature and causes an increase in the number of accessible GDP‐binding sites.

Comparative study of the life cycle dependent post-translation modifications of protein synthesis elongation factor Tu present in the membrane proteome of streptomycetes and mycobacteria

“…Sedimented pellets resuspended in a small amount of buffer A were used as a "membrane fraction". EF-Tu from S. aureofaciens was purified according to Weiser et al (1982). To prove the embedding of EF-Tu in membranes we centrifuged the membrane fraction in the SS-34 rotor through 30 % sucrose cushion (20 000 rpm, 1 h).…”

The use of glass beads cultivation system to study the global effect of the ppk gene inactivation in Streptomyces lividans

“…6), might be explained by storage of the factor for later use. We have previously shown that Streptomycetes EF-Tu can spontaneously aggregate (Weiser et al 1981(Weiser et al , 1982; this mechanism may be utilised by differentiating cells to store EF-Tu.…”

Content, distribution and stability of protein-synthesis elongation factor Tu in subcellular fractions of vegetative cells and spores of Streptomyces aureofaciens

“…In our previous studies we compared some of the functional and structural properties of EF-Tu from Streptomyces aureofaciens vegetative mycelium and E. co# which revealed a high degree of functional and structural similarity between the two proteins [4][5][6]. Here we have identified the EF-Tu in spores of S. aureofaciens and we describe a membrane bound protease from spores which cleaves the EF-Tu in spore cell-free homogenates.…”