The primary structure of protein BL17 isolated from the large subunit of theBacillus stearothermophilusribosome

Structure of a cyanobacterial gene encoding the 50S ribosomal protein L9

The rplI gene encoding the ribosomal protein L9 was found 4 kbp downstream from the desA gene, but on the opposite strand, in the genome of the cyanobacterium Synechocystis PCC6803. The deduced amino acid sequence is homologous to the sequences of the L9 proteins from Escherichia coli and chloroplasts of Arabidopsis and pea. The gene is present as a single copy in the chromosome and is transcribed as a mRNA of 0.64 kb. An open reading frame of unknown function (ORF291) was found in the upstream region of the rplI gene.

Cloning, overexpression, purification and crystallisation of ribosomal protein L9 from Bacillus stearothermophilus

The cloning, sequencing and overexpression of the gene coding for Bacillus stearothermophilus ribosomal protein L9 is described. The sequence corresponds directly to that presented for the protein itself by classical methods, differing at only a few amino acid positions. The purification and crystallisation of the corresponding L9 protein is presented. The crystals are isomorphous to those described for L9 obtained by conventional methods.

Nucleotide sequences of cDNAs encoding four complete nuclear-encoded plastid ribosomal proteins

The nucleotide sequences of four pea nuclear-encoded plastid ribosomal protein cDNAs have been determined. These cDNAs were shown to encode the complete precursor proteins. The transit sequences of the encoded proteins are similar to the transit sequences of other imported proteins being rich in serine and/or threonine and lacking aspartic and glutamic acid. The transit sequences do not, however, have any apparent amino acid sequence similarity with one another or with the transit sequences of other imported proteins. The derived amino acid sequences of the plastid ribosomal proteins were compared to the amino acid sequences of other ribosomal proteins. Significant amino acid sequence similarity was found between Escherichia coli ribosomal proteins L9 and L24 and two of the nuclear-encoded pea plastid ribosomal proteins.

The complete amino acid sequences of ribosomal proteins L17, L27, and S9 from Bacillus stearothermophilus

The complete primary structures of proteins L17, L27 and S9 extracted from the Bacillus stearothermophilus ribosomes with 1 M NaCl and purified to homogeneity by column chromatography have been determined. The amino acid sequences of these proteins are compared to those of the homologous ribosomal proteins from Escherichia coli. The number of identical amino acid residues between the homologous proteins lies between 33-55%.

Ribosomal proteins: their structure and spatial arrangement in prokaryotic ribosomes

During the last 15 years of ribosomal protein study, enormous progress has been made. Each of the proteins from E. coli ribosomes has been isolated, sequenced, and immunologically and physically characterized. Ribosomal proteins from other sources (e.g., from some bacteria, yeast, and rat) have been isolated and studied as well. Several proteins have recently been crystallized, and from the X-ray studies it is expected that much important information on the three-dimensional structure will be forthcoming. Many other proteins can probably be crystallized if suitable preparative procedures and crystallization conditions are found. Tremendous progress has also been made in deciphering the architecture of the ribosome. A battery of different methods has been used to provide the nearest neighbor distances of the ribosomal proteins in situ. Definitive measurements are now emanating from neutron-scattering experiments which also promise to give reasonably accurate radii of gyration of the proteins in situ. In turn, refined immune electron microscopy results supplement the neutron-scattering data and also position the proteins on the subunits themselves. This cannot be done by the other methods. Determination of the three-dimensional RNA structure within the ribosome is still in its infancy. Nonetheless, it is expected that by combining the data from protein-RNA and from RNA-RNA cross-linking studies, the structure of the RNA in situ can be unraveled. Of great interest is the fact that ribosomal subunits and ribosomes themselves have now been crystallized, and low-resolution structural maps have already been obtained. However, to grow suitable crystals and to resolve the ribosomal structure at a sufficiently high resolution remains a great challenge and task to biochemists and crystallographers.