[The effect of mutations in ribosomal proteins S4, S12 and L7/L12 on EF-Tu-dependent expenditure of GTP in the process of codon-specific elongation and misreading of poly(U)].
The effect of mutations in ribosomal proteins S4 (rpsD12), S12 (rpsL282) and L7/L12 (rplL265) of Escherichia coli K12 on the EF-Tu-dependent expenditure of GTP during codon-specific elongation (poly(Phe) synthesis on poly(U] and misreading (poly(Leu) synthesis on poly(U], was studied. Under the conditions used the mutations in proteins S4 and L7/L12 did not practically affect the EF-Tu-dependent expenditure of GTR during the poly(Phe) synthesis on poly(U): the GTP/Phe ratio was about 1, as in the case of the wild strain. Under the same conditions, the ribosomes with a mutant S12 protein tended to discard some amount of Phe-tRNA, as a result of which the GTP/Phe ratio increased to about 3. The marked inhibition of misreading by ribosomes with a mutant S12 protein was accompanied by a significant increase of GTP expenditure at the stage of EF-Tu-dependent non-cognate aminoacyl-tRNA binding. In mutant S 12 proteins the GTP/Leu ratio was about 30-40, whereas in the wild type it was about 12. In contrast, stimulation of misreading by ribosomes with mutant S4 and L7/L12 proteins was accompanied by a decrease of the EF-Tu-dependent expenditure of GTP by 2-3 GTP molecules per one Leu residue included into the peptide.
Kakhniashvili
D G
DG
Gavrilova
L P
LP
D003062:Codon; D004926:Escherichia coli / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism*; D009154:Mutation; D010444:Peptide Elongation Factor Tu / Q000378:metabolism*; D011072:Poly U / Q000378:metabolism*; D012269:Ribosomal Proteins / Q000235:genetics*
D003062:Codon; D012269:Ribosomal Proteins; C034212:ribosomal protein S12; C031798:ribosomal protein S4; D011072:Poly U; C016700:ribosomal protein L7-L12; D006160:Guanosine Triphosphate; D010444:Peptide Elongation Factor Tu
Vliianie mutatsiĭ v ribosomnykh belkakh S4, S12, i L7/L12 na EF-Tu- zavisimyĭ raskhod GTP v protsesse kodon-spetsifichnoĭ élongatsii i lozhnogo schityvaniia poli(U).