Subunit homology between Escherichia coli, mitochondrial and chloroplast ribosomes

Grivell, L.A.; Walg, H.L.

doi:10.1016/0006-291x(72)90502-5

Cited by 34 publications

(11 citation statements)

References 9 publications

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“…hybrids, no monosome formation occurs with subunits derived from mitochondrial and bacterial ribosomes [13]. The exchange of smaller components of the protein synthesis systems, however, is possible at least in an uni-directional way as shown for peptide chain elongation factors from Neurospora and yeast and Escherichia coli ribosomes [6,7].…”

Section: Discussionmentioning

confidence: 99%

Mammalian Mitochondrial Ribosomes. Studies on the Exchangeability of Polypeptide Chain Elongation Factors from Bacterial and Mitochondrial Systems

1980

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Mammalian mitochondrial ribosomes from rat liver synthesised poly(phenyla1anine) from ['"CIPhe-tRNA in the presence of a homologous lo5 x g,, supernatent fraction. The activity depended on the addition of synthetic template and was resistant to cycloheximide. The polyanion spermidine had a stimulatory effect on peptide synthesis in vitro. In contrast to Escherichiu coli ribosomes, which also functioned with heterologous supernatant fractions, 55-S mitochondrial ribosomes were inactive when supplemented with heterologous supernatant fractions from E. coli or with purified bacterial elongation factors. EF-T slightly stimulated polyphenylalanine synthesis when added in combination with mitochondrial supernatant fractions. Two-dimensional electrophoretic analysis of the protein content of both supernatant fractions revealed considerable differences in the distribution of the species-specific proteins according to their isoelectric points. The mitochondrial superand the few acidic proteins did not co-migrate with natant proteins were in general more basic EF-Tu or EF-G from E. coli.Mammalian mitochondrial ribosomes represent a special group among organelle ribosomes. They display an unusually high protein content [l -31 and evolved fairly rapidly compared with cytoplasmic ribosomes [4]. Like all other mitochondrial ribosomes they contain binding sites for inhibitors of bacterial protein synthesis while being unaffected by antibiotics such as cycloheximide and anisomycin which interfere with eucaryotic ribosome function. Although differences have been observed between ribosomes from bacteria and mammalian mitochondria in the interaction with antibiotics binding to the ribosomal P-site, 55-S ribosomes can be classed as procaryotic by functional parameters [5].The degree of similarity between bacterial and mitochondrial mechanisms of protein synthesis can be expressed by the interchangeability of protein synthesis factors, ribosomal proteins, or even ribosomal subunits. In the bacterial system mitochondrial peptide chain elongation factors from yeast and Neurosporu were successfully substituted in place of Escherichiu coli factors [6,7], but the reverse experiment appeared to be limited by the low activity of isolated mitochondrial ribosomes in protein synthesis in vitro. Isolation of active mitochondrial ribosomes free of endogenous elongation factors therefore was a prerequisite to study the specificity of bacterial and mitochondrial peptide chain elongation factors. The present investigation reports on the ability of supernatant fractions from rat liver mitochondria and from E. coli to stimulate peptide synthesis in homologous and heterologous systems. The protein composition of both 1 O5 x g,, supernatant fractions was compared by two-dimensional gel electrophoresis applying isoelectric focusing in the first dimension. MATERIALS AND METHODS MateriulsRadioactive amino acids and [3H]poly(U) were obtained from Amersham, Great Britain. A11 reagents were of analytical grade. Solutions were prepared in sterilized glasswar...

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Section: Discussionmentioning

confidence: 99%

Mammalian Mitochondrial Ribosomes. Studies on the Exchangeability of Polypeptide Chain Elongation Factors from Bacterial and Mitochondrial Systems

1980

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“…Both chloroplast and bacterial ribosomes from wild-type cells exhibit sensitivity to the same set of antibiotics; similar mutations conferring antibiotic resistance and dependence have been described in both systems; and resistances have been localized to the same subunit in Chlamydomonas and bacteria (8). Subunit homology between bacterial and chloroplast ribosomes has been shown to be high and hybrid ribosomes are active in polypeptide synthesis (20).…”

Section: Methodsmentioning

confidence: 99%

Localization of Five Antibiotic Resistances at the Subunit Level in Chloroplast Ribosomes of Chlamydomonas

Schlanger

Sager

1974

Proc. Natl. Acad. Sci. U.S.A.

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The chloroplast ribosomes from five antibiotic resistant strains of Chlamydomonas, each carrying one mutant gene mapping in chloroplast DNA, have been shown to be resistant to the corresponding antibiotic in a poly(U)-directed amino-acid incorporating assay system. The alteration conferring resistance was localized to the 30S subunit in ribosomes from streptomycin, neamine, and spectinomycin resistant strains, and to the 50S subunit in ribosomes from cleocin and carbomycin resistant strains. Spectinomycin resistant ribosomes showed no cross-resistance to any other drugs, but limited crossresistance was noted with the other mutant ribosomes. The similarity between these findings and results reported by others with bacterial ribosomes supports our hypothesis that at least some chloroplast ribosomal proteins are coded by genes in chloroplast DNA.Organelle DNAs with coding potential for many proteins are present in the mitochondria and chloroplasts of all eukaryotic cells (1). In general, chloroplast DNAs with a genomic size of at least 108 daltons (2) may code for several hundred proteins, while the 5-,4m circular mitochondrial DNAs of animal cells mav code for no more than 20 to 30 proteins (3). A well-established function of organelle DNAs is as template for the transcription of organelle ribosomal and transfer RNAs (1); the evidence is accumulating that some proteins associated with organelle function, i.e., photosynthesis and respiration, are determined by organelle genes (4, 5). Are some or all of the organelle ribosomal proteins also coded by the corresponding organelle DNA? This paper presents evidence that 70S chloroplast ribosomes isolated from each of five antibiotic resistant mutant strains of Chlamydomonas are resistant to the corresponding antibiotic, as a result of alterations localized to the level of ribosomal subunits. Mutations conferring resistance to streptomycin (sm2), neamine (nea), spectinomycin (spc), carbomycin (car), and cleocin (cle) each show non-Mendelian inheritance and map in a single linkage group (1, 6, 7). Results to be reported here provide further evidence that this linkage group is located in chloroplast DNA; 70S ribosomes and reassociated subunits from wild-type and five resistant mutant strains each carrying one of these mutant genes were examined for their antibiotic resistance in a poly(U)-directed phenylalanine incorporating system. Resistances to streptomycin, neamine, and spectinomycin were localized to the 30S subunit, and resistances to cleocin and carbomycin to the 50S subunit. The pattern of subunit localization, mirroring that found in bacterial ribosomes (8) as well as the low levels of cross-resistance between mutants, provide strong, albeit indirect, evidence that each of the mutant genes responsible for resistance codes for a chloroplast ribosomal protein. Several lines of evidence 1715 that non-Mendelian mutations to drug resistance in Chlamydomonas induce alterations in chloroplast ribosomes have been previously reported (7, 9-13).

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“…In general, chloroplast ribosomes reveal higher homology with the sensitive to chloramphenicol bacterial-type ribosomes than with those found in mitochondria. A highly comprehensive comparison of subunit sequences, taken from spinach chloroplasts, yeast mitochondria, and Escherichia coli, was presented by Grivell and Walg (1972). The similarities of plastids and ribosomes to bacterial ribosome make the former potentially sensitive for chloramphenicol, allowing us to neglect the influence of chloramphenicol on mitochondrial ribosomes of C. merolae.…”

Section: Introductionmentioning

confidence: 99%

Chloramphenicol acetyltransferase—a new selectable marker in stable nuclear transformation of the red alga Cyanidioschyzon merolae

et al. 2015

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In this study, we have shown the applicability of chloramphenicol acetyltransferase as a new and convenient selectable marker for stable nuclear transformation as well as potential chloroplast transformation of Cyanidioschyzon merolae-a new model organism, which offers unique opportunities for studding the mitochondrial and plastid physiology as well as various evolutionary, structural, and functional features of the photosynthetic apparatus.

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Subunit homology between Escherichia coli, mitochondrial and chloroplast ribosomes

Cited by 34 publications

References 9 publications

Mammalian Mitochondrial Ribosomes. Studies on the Exchangeability of Polypeptide Chain Elongation Factors from Bacterial and Mitochondrial Systems

Mammalian Mitochondrial Ribosomes. Studies on the Exchangeability of Polypeptide Chain Elongation Factors from Bacterial and Mitochondrial Systems

Localization of Five Antibiotic Resistances at the Subunit Level in Chloroplast Ribosomes of Chlamydomonas

Chloramphenicol acetyltransferase—a new selectable marker in stable nuclear transformation of the red alga Cyanidioschyzon merolae

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