Mutations in the G-domain of elongation factor G from Thermus thermophilusaffect both its interaction with GTP and fusidic acid

Citation
Ka. Martemyanov et al., Mutations in the G-domain of elongation factor G from Thermus thermophilusaffect both its interaction with GTP and fusidic acid, J BIOL CHEM, 276(31), 2001, pp. 28774-28778
Citations number
33
Categorie Soggetti
Biochemistry & Biophysics
Journal title
JOURNAL OF BIOLOGICAL CHEMISTRY
ISSN journal
00219258 → ACNP
Volume
276
Issue
31
Year of publication
2001
Pages
28774 - 28778
Database
ISI
SICI code
0021-9258(20010803)276:31<28774:MITGOE>2.0.ZU;2-K
Abstract
Two hypersensitive and two resistant variants of elongation factor-G (EF-G) toward fusidic acid are studied in comparison with the wild type factor. A ll mutated proteins are active in a cell-free translation system and riboso me-dependent GTP hydrolysis. The EF-G variants with the Thr-84 --> Ala or A sp-109 --> Lys mutations bring about a strong resistance of EF-G to the ant ibiotic, whereas the EF-Gs with substitutions Gly-16 --> Val or Glu-119 --> Lys are the first examples of fusidic acid-hypersensitive factors. A corre lation between fusidic acid resistance of EF-G mutants and their affinity t o GTP are revealed in this study, although their interactions with GDP are not changed. Thus, fusidic acid-hypersensitive mutants have the high affini ty to an uncleavable analog, but the association of resistant mutants with GTP is decreased. The effects of either fusidic acid-sensitive or resistant mutations can be explained by the conformational changes in the EF-G molec ule, which influence its GTP-binding center. The results presented in this paper indicate that fusidic acid-sensitive mutant factors have a conformati on favorable for GTP binding and subsequent interaction with the ribosomes.