The mitochondrial ribosome from <i>Locusta migratoria</i>: Dissociation into subunits

Kleinow, W.; Neupert, Walter

doi:10.1016/0014-5793(71)80334-4

Cited by 20 publications

(9 citation statements)

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“…The mitochondrial ribosomes constitute 2-5% of total cellular ribosomes. They can be clearly distinguished from cytoplasmic ribosomes by sedimentation velocity, size of ribosomal R N A , protein composition, and sensitivity against chloramphenicol and cycloheximide (1,2,4). In this paper we report that mitochondrial ribosomes, despite their unusual low sedimentation constant, show morphological features very similar to those of undissociated 80S cytoplasmic ribosomes from the same tissue.…”

Section: Introductionmentioning

confidence: 73%

“…We have described the isolation of ribosomes from the mitochondria of thoracic muscle of Locusta migratoria (1,2). These ribosomes carry nascent peptide chains into which radioactive amino acids are incorporated in vitro as well as in vivo in the presence of cycloheximide (1,2). The ribosomes show a sedimentation constant of about 60S with all preparative and analytical methods used in our experiments, provided that a dissociation into subunits was avoided.…”

Section: Introductionmentioning

confidence: 99%

“…The ribosomes show a sedimentation constant of about 60S with all preparative and analytical methods used in our experiments, provided that a dissociation into subunits was avoided. In magnesium-free gradients the ribosomes dissociate into subunits with sedimentation constants of 40S and 25S (2). After dissociation the 40S subunits carry nascent peptide chains, a finding characteristic for large ribosomal subunits (1).…”

Section: Introductionmentioning

confidence: 99%

“…pages 860-875 40S and 25S subunits, respectively, as well as from the 60S ribosomes and from whole purified mitochondria (3,4). The proteins from the 40S and 25S subunits display different electrophoretic patterns (2). The mitochondrial ribosomes constitute 2-5% of total cellular ribosomes.…”

Section: Introductionmentioning

confidence: 99%

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ELECTRON MICROSCOPE STUDY OF MITOCHONDRIAL 60S AND CYTOPLASMIC 80S RIBOSOMES FROM LOCUSTA MIGRATORIA

Kleinow

Neupert

Miller

1974

The Journal of Cell Biology

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Purified mitochondrial ribosomes (60S) have been isolated from locust flight muscle. Purification could be achieved after lysis of mitochondria in 0.055 M MgCl2. Mitochondrial 60S and cytoplasmic 80S ribosomes were investigated by electron microscopy in tissue sections, in sections of pellets of isolated ribosomes, and by negative staining of ribosomal suspensions. In negatively stained preparations, mitochondrial ribosomes show dimensions of ∼270 x 210 x 215 Å; cytoplasmic ribosomes measure ∼295 x 245 x 255 Å. From these values a volume ratio of mitochondrial to cytoplasmic ribosomes of 1: 1.5 was estimated. Despite their different sedimentation constants, mitochondrial ribosomes after negative staining show a morphology similar to that of cytoplasmic ribosomes. Both types of particles show bipartite profiles which are interpreted as "frontal views" and "lateral views." In contrast to measurements on negatively stained particles, the diameter of mitochondrial ribosomes in tissue sections is ∼130 Å, while the diameter of cytoplasmic ribosomes is ∼ 180–200 Å. These data suggest a volume ratio of mitochondrial to cytoplasmic ribosomes of 1:3. Subunits of mitochondrial ribosomes (40S and 25S) were obtained by incubation under dissociating conditions before fixation in glutaraldehyde. After negative staining, mitochondrial large (40S) subunits show rounded profiles with a shallow groove on a flattened side of the profile. Mitochondrial small subunits (25S) display elongated, triangular profiles.

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Section: Introductionmentioning

confidence: 73%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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ELECTRON MICROSCOPE STUDY OF MITOCHONDRIAL 60S AND CYTOPLASMIC 80S RIBOSOMES FROM LOCUSTA MIGRATORIA

Kleinow

Neupert

Miller

1974

The Journal of Cell Biology

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“…Freezing the mitochondrial lysate after performing the clarifying spin results, however, in a lower amount of protein accompanying the mitochondrial ribosomes. Cytoplasmic ribosomes were prepared as described [6] . In this case, muscles were homogenised in buffer III (300mM sucrose, lOmM MgCta, lOmM triethanolarnine-HC1, pH 7.2).…”

Section: Methodsmentioning

confidence: 99%

Influence of Cations on the Dissociation of Mitochondrial and Cytoplasmic Ribosomes fromLocusta migratoria

Kleinow¹

1974

Hoppe-Seyler´s Zeitschrift für physiologische Chemie

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Ribosomes were isolated from the cytoplasm and from purified mitochondria of Locusta migratoria thoracic muscle. Gradient profiles of mitochondrial and of cytoplasmic ribosomes were compared after centrifugation in sucrose density gradients of various ionic compositions. Mitochondrial and cytoplasmic ribosomes dissociate into subunits at low concentrations of magnesium (or calcium) in the gradient. Mitochondrial ribosomes were found to be more sensitive to low concentrations of these bivalent cations than cytoplasmic ribosomes. Mitochondrial, but not cytoplasmic, ribosomes tend to dissociate also at high (50-100mM) concentrations of Mg 2 ® or Ca 2 ®. In spermidine-containing gradients, mitochondrial ribosomes sediment as monoribosomes, whereas cytoplasmic ribosomes aggregate extensively. The effects of spermidine are counteracted by the presence of NH4C1 in the gradients. Beeinflußbarkeit der Dissoziation mitochondrialer und cytoplasmatischer Ribosomen aus Locusta migratoria durch KationenZusammenfassung: Aus dem Thoraxmuskel von Locusta migratoria wurden die cytoplasmatischen und die mitochondrialen Ribosomen isoliert und ihre Gradientenprofile nach Zentrifugation in Saccharosedichtegradienten verschiedener lonenzusammensetzung miteinander verglichen. Beide Ribosomentypen dissoziieren bei niedrigen Magnesium-(oder Calcium-)konzentrationen im Gradientenmedium. Die mitochondrialen Ribosomen erweisen sich dabei als empfindlicher gegen niedrige Konzentrationen an diesen zweiwertigen Kationen als die cytoplasmatischen Ribosomen. Bei den mitochondrialen, nicht aber bei den cytoplasmatischen Ribosomen, wirken auch hohe Mg 2 ®-oder Ca 2 ®-Konzentrationen (50-lOOmw) dissoziierend. Spermidin begünstigt bei den mitochondrialen Ribosomen das Auftreten von Monoribosomen, bei den cytoplasmatischen Ribosomen führt es zur Aggregation. Die Anwesenheit von NEUCl im Gradienten wirkt diesen Einflüssen des Spermidins entgegen.

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The Mitochondrial Translation System

Buetow

Wood

1978

Subcellular Biochemistry

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The mitochondrial ribosome from Locusta migratoria: Dissociation into subunits

Cited by 20 publications

References 17 publications

ELECTRON MICROSCOPE STUDY OF MITOCHONDRIAL 60S AND CYTOPLASMIC 80S RIBOSOMES FROM LOCUSTA MIGRATORIA

ELECTRON MICROSCOPE STUDY OF MITOCHONDRIAL 60S AND CYTOPLASMIC 80S RIBOSOMES FROM LOCUSTA MIGRATORIA

Influence of Cations on the Dissociation of Mitochondrial and Cytoplasmic Ribosomes fromLocusta migratoria

The Mitochondrial Translation System

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