Open AccessThe Mode of Action of Thiostrepton in the Initiation of Protein Synthesis
Author(s) -
NAAKTGEBOREN Nico,
ROOBOL Kees,
GUBBENS Jos,
VOORMA Harry O.
Publication year - 1976
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1976.tb10953.x
Subject(s) - thiostrepton , gtp' , protein biosynthesis , ribosome , protein subunit , chemistry , biophysics , biochemistry , biology , microbiology and biotechnology , enzyme , rna , gene
The inhibition by thiostrepton of the initiation of protein synthesis is exerted at a different level from the inhibition of reactions mediated by EF‐Tu and EF‐G in the elongation of protein synthesis. The presence of thiostrepton on the 50‐S subunit completely prevents the binding of the EFT‐Tu ? GTP ? aa‐tRNA complex and EF‐G ? GTP complex to the 70‐S ribosome, resulting in cessation of protein synthesis at a concentration of 1 μM thiostrepton. On the other hand, during initiation thiostrepton impairs the coupling of the 50‐S subunit with the 30‐S initiation complex, indirectly causing inhibition of IF‐2‐dependent reactions. Impairment of the coupling is strongly influenced by the conditions of incubation. Siace formation of formylmethionylpuromycin and the IF‐2‐dependent GTP hydrolysis are inhibited to the same extent and recycling of IF‐2 can take place in the presence of thiostrepton, we conclude that the basic mechanism of inhibition of initiation differs from that of inhibition of elongation.