The proteins in membrane and cytoplasmic ribosomes of Streptococcus fecalis. An extra protein in the 50-S subparticles of cytoplasmic ribosomes
| Autor: | Adolph Abrams, D.G. Brown |
|---|---|
| Rok vydání: | 1970 |
| Předmět: |
Electrophoresis
Cytoplasm Detergents Biology Biochemistry Genetics and Molecular Biology (miscellaneous) Ribosome Ammonium Chloride chemistry.chemical_compound Bacterial Proteins Ribosomal protein Centrifugation Density Gradient Enterococcus faecalis Methods Sodium dodecyl sulfate Polyacrylamide gel electrophoresis Isoelectric focusing Cell Membrane Molecular Weight Microscopy Electron Isoelectric point Acrylates Solubility Biochemistry chemistry Ultracentrifuge Isoelectric Focusing Peptides Gels Ribosomes Ultracentrifugation |
| Zdroj: | Biochimica et Biophysica Acta (BBA) - Protein Structure. 200:522-537 |
| ISSN: | 0005-2795 |
| DOI: | 10.1016/0005-2795(70)90108-x |
| Popis: | 1. 1.|The existence of both membrane-associated and cytoplasmic ribosomes in Streptococcus fecalis prompted us to investigate whether or not they are identical. Ribosomes were isolated from the cytoplasmic and membrane fractions of Streptococcus fecalis (ATCC No. 9790). When compared in the analytical ultracentrifuge, the two sets of ribosomes were indistinguishable and consisted of about a 1:1 mixture of 52- and 33-S subparticles. The proteins from both sets of ribosomes were extracted with acetic acid and were compared by electrophoresis at pH 4.2 in slabs of polyacrylamide gel containing 7.5 M urea. The electrophoretic pattern of the protein of the 52-S subparticles usually contains about 17 major bands while that of the 33-S subparticles contains about 14 major bands. 2. 2.|Although there was general similarity between the electrophoretic patterns of the total ribosomal proteins, the cytoplasmic ribosomes consistently contained a protein which is absent from membrane ribosomes. Analysis of the proteins extracted from the 52- and 33-S subparticles reveals that the extra protein in the cytoplasmic ribosomes belongs exclusively to the 52-S subparticle. Since the extra protein was not detected in the membrane 52-S subparticles or in any nonribosomal cell fraction, we have designated it as the C50-X protein. 3. 3.|The C50-X protein was extracted from cytoplasmic ribosomes using NH4Cl between 0.5 and 1.0 M; it was then purified by electrofocusing in the presence of 6 M urea. The C50-X protein has an isoelectric point of 5.9 and appears to be a single polypeptide chain. Electrophoretic analysis in polyacrylamide gels containing 0.1% sodium dodecyl sulfate indicates that the C50-X protein has a molecular weight of approx. 45 000. 4. 4.|These results indicate that the membrane and cytoplasmic ribosomes isolated from Streptococcus fecalis are not completely identical with respect to the protein components in the 50-S subparticle. |
| Databáze: | OpenAIRE |
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