Hyper-accurate ribosomes inhibit growth.
AUTOR(ES)
Ruusala, T
RESUMO
We have compared both in vivo and in vitro translation by ribosomes from wild-type bacteria with those from streptomycin-resistant (SmR), streptomycin-dependent (SmD) and streptomycin-pseudo-dependent (SmP) mutants. The three mutant bacteria translate more accurately and more slowly in the absence of streptomycin (Sm) than do wild-type bacteria. In particular, the SmP bacteria grow at roughly half the rate of the wild-type in the absence of Sm. The antibiotic stimulates both the growth rate and the translation rate of SmP bacteria by approximately 2-fold, but it simultaneously increases the nonsense suppression rate quite dramatically. Kinetic experiments in vitro show that the greater accuracy and slower translation rates of mutant ribosomes compared with wild-type ribosomes are associated with much more rigorous proofreading activities of SmR, SmD and SmP ribosomes. Sm reduces the proofreading flows of the mutant ribosomes and stimulates their elongation rates. The data suggest that these excessively accurate ribosomes are kinetically less efficient than wild-type ribosomes, and that this inhibits mutant growth rates. The stimulation of the growth of the mutants by Sm results from the enhanced translational efficiency due to the loss of proofreading, which more than offsets the loss of accuracy caused by the antibiotic.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=557732Documentos Relacionados
- X-ray crystal structures of the WT and a hyper-accurate ribosome from Escherichia coli
- Pseudomonas aeruginosa pyocyanin and 1-hydroxyphenazine inhibit fungal growth.
- Binding of novel macrolide structures to macrolides-lincosamides-streptogramin B-resistant ribosomes inhibits protein synthesis and bacterial growth.
- Radiographic centiles of lung and heart growth. Patterns of growth.
- Association of Plant p40 Protein with Ribosomes Is Enhanced When Polyribosomes Form during Periods of Active Tissue Growth.