Binding sites of E. coli and B. stearothermophilus ribosomal proteins on B stearothermophilus 5S RNA.

The primary binding sites for Bacillus stearothermophilus proteins B-L5 and B-L22 and the Escherichia coli proteins E-L5, E-L18 and E-L25 on B. stearothermophilus 5S RNA were determined by limited ribonuclease digestion of the corresponding 5S RNA-protein complexes. The results obtained in this study are in agreement with our previous experiments in which the binding sites of E.

Identification of Escherichia coli and Bacillus stearothermophilus ribosomal protein binding sites on Escherichia coli 5S RNA.

E coli [32P]-labelled 5S RNA was complexed with E. coli and B. stearothermophilus 50S ribosomal proteins.

Escherichia coli 5S RNA binding proteins L18 and L25 interact with 5.8S RNA but not with 5S RNA from yeast ribosomes.

Reconstitution experiments showed that the two Escherichia coli 5S RNA binding proteins L18 and L25 form a specific complex with yeast 5.8S RNA and not with yeast 5S RNA. The yeast 5.

Regions of tRNA important for binding to the ribosomal A and P sites.

Studies on the enzymatic inhibition of phenylalanyl-tRNAPhe and formylmethionyl-tRNAFMet binding to the ribosomes by defined tRNA fragments indicate that beside the anticodon the following regions of tRNA are important for ribosomal A-site interaction: the TppsipCp sequence, the CpCpA end, and hU loop. In contrast, binding to the ribosomal P site is not inhibited by the fragments of uncharged yeast tRNAPhe containing the hU or the TpsiC loop of the molecule. Comparative studies on the inhibitory effect of the oligonucleotides TppsipCpGp and UpUpCpGp indicate that the presence of the minor bases in TpsiC loop is not an essential prerequisite for the binding of tRNA to the ribosomal A site.

Neutron scattering measurements with the label triangulation method on the 50 S subunit of E. coli ribosomes.

In the E. coli 50 S ribosomal subunit, proteins L7/L12 and L10 were deuterated by partial reconstitution. The distance between L7/L12 and L10 was measured by the label triangulation method and was found to be approximately 100 A or, with low probability, 60 to 70 A, depending on the concentration.

ATPase and GTPase activities associated with the 5-S RNA-protein complex of Escherichia coli ribosomes.

Specific 5-S RNA-protein complexes were reconstituted from Escherichia coli 5-S RNA and 50-S ribosomal proteins. These complexes consist of 5-S RNA and two major proteins, namely E-L18 and E-L25. Analysis for enzymatic activities shows that ATP and GTP are hydrolyzed and that this hydrolysis is independent of elongation factors.

A new transfer RNA fragment reaction: Tp psi pCpGp bound to a ribosome-messenger RNA complex induces the synthesis of guanosine tetra- and pentaphosphates.

The tetranucleotide TpPsipCpGp, when bound to Escherichia coli 50S ribosomal subunits, can replace intact tRNA in the stringent factor-directed synthesis of guanosine tetra- and pentaphosphates. The TpPsipCpGp-dependent fragment reaction has a strict requirement for the 50S and 30S ribosomal subunits and synthetic or natural messenger RNA.