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Struktura a funkce tmRNA u streptomycet
Bobek, Jan ; Palečková, Petra ; Mikulík, Karel
The functional trans-translation system is important to allow survival of antibiotic producing microorganism under unfavourable conditions. The ssrA genes from S. coelicolor, S. collinus, S. aureofaciens and S. griseus were amplified and subjected to sequence analysis. To investigate the role of tmRNA in streptomycetes we have examined the level of tmRNA during the growth and differentiation under various physiological conditions
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Aktivace translačního systému v průběhu buněčné diferenciace streptomycet
Bobek, Jan ; Palečková, Petra ; Vohradský, Jiří ; Mikulík, Karel
Synchronously germinating spores of S. granaticolor were used to study the activation of translational system and expression of proteins. Proteomic approach was used to gain more information on expression of proteins during germination on two types of media differing in ability of cells to produce antibiotic granaticin. The requirement of functional trans-translational system for reactivation of translation in S. aureofaciens exposed to unfavourable conditions was examined. Abundance of tmRNA is connected with changes in the rate of translation and with the accumulation of tetracycline. Our data indicate that trans-translation could be involved in self-defence against antibiotics synthesized
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Delece RPS0A-vazebné domény TIF32/eIF3A brání vazbě MFC na 40S ribozóm a blokuje derepresi GCN4 exprese
Szamecz, Bela ; Rutkai, Edit ; Nielsen, K. H. ; Valášek, Leoš
Yeast Initiation factor 3 (eIF3) occurs together with the eIF2.GTP.Met-tRNAiMet ternary complex (TC) and eIFs 1 and 5 in a pre-formed unit designated the multifactor complex (MFC) that was implicated in playing a critical role in ecient recruitment of TC and mRNA to the 40S ribosomes and stimulation of the post-assembly processes such as scanning and AUG recognition. In ecort to identify binding sites of the MFC on the 40S ribosome, we previously demonstrated that deletion of the rst 199 amino acids of the N-terminal domain (NTD) of the TIF32 subunit of eIF3/eIF3a, in the presence of a wild-type gene, completely eliminated association of the mutant MFC with the 40S ribosome without aecting its overall integrity. In addition, we showed that the TIF32-NTD contains a binding site for the C-terminal domain (CTD) of the small ribosomal protein 0A (RPS0A) that is located on the solvent side of the 40S subunit where the main body of eIF3 was proposed to reside
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C-konc. segment NIP1/eIF3c a HCR1 subjednotky eIF3 umožňují jeho vazbu na 40S ribozóm přes RPS33/ASC1 a RPS22
Rutkai, Edit ; Herrmannová, Anna ; Szamecz, Bela ; Valášek, Leoš
One of the rst critical steps of protein synthesis is the recruitment of the eIF2.GTP.Met-tRNAiMet ternary complex (TC) to the 40S ribosome. In yeast, the TC occurs together with eIFs 1, 3 and 5 in a Multifactor complex (MFC) that was shown to function as an important intermediate of the initiation pathway. Our previous study determined several critical domains of the TIF32 and NIP1 subunits of yeast eIF3, the deletion of which, in the background of a wild type gene, signifcantly aected binding of the mutant MFC to the 40S ribosomes. Subsequent identifcation of the two contact points between TIF32 and components of the 40S ribosome enabled us to propose that the major body of the eIF3 complex resides under the head region on the solvent side of the small ribosomal subunit facing down towards its left foot
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