The binding of ribosomal protein S1 to S1-depleted 30S and 70S ribosomes. A fluorescence anisotropy study of the effects of Mg2+.
AUTOR(ES)
Goss, D J
RESUMO
We have determined the equilibrium constants for the binding of AEDANS-labelled S1 to S1-depleted 30S and 70S ribosomes. For "tight" ribosomes, the association of S1 increases with the sixth power of Mg2+ concentration, but for 30S subunits and "loose" ribosomes, there is virtually no dependence of the association on Mg2+ over the same concentration range, 2-10 mM in Mg2+. The binding of S1 to 70S ribosomes at 10 mM Mg2+ is stabilized by 2 kcal/mol compared to the binding to 30S subunits. When intact S1 binds to tight ribosomes, the fluorescence anisotrophy is that for virtually complete rotational immobilization. The anisotropies vary considerably with the preparation and treatment of both S1 and ribosomes and these variations are detailed here. The results suggest the linkage of Mg2+-dependent conformational changes in the intact ribosomes, perhaps including rRNA, and the binding of S1.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=326299Documentos Relacionados
- The binding of 6-demethylchlortetracycline to 70S, 50S and 30S ribosomal particles: a quantitative study by fluorescence anisotropy.
- Chain initiation factor 3 crosslinks to E. coli 30S and 50S ribosomal subunits and alters the UV absorbance spectrum of 70S ribosomes.
- Nucleic acid helix-unwinding properties of ribosomal protein S1 and the role of S1 in mRNA binding to ribosomes.
- Interaction of Escherichia coli ribosomal protein S1 with ribosomes.
- Leaderless mRNAs Bind 70S Ribosomes More Strongly than 30S Ribosomal Subunits in Escherichia coli