Structural differences between ribosomes of various eukaryotes: stability, density, mass, size and structure in solution of cytoplasmic ribosomes from Tetrahumena, Artemia and Euglena |
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Authors: | Paul Nieuwenhyse Julies Clauwaert Gerard Ledoigt Jean-Jacques Curgy |
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Affiliation: | Department of Cell Biology, University of Antwerp, B 2610, Wilrijk, Belgium Laboratoire de Cytophysiologie de la Photosynthèse, Centre National de la Recherche Scientifique, Gif-sur-Yvette, France Laboratoire de Biologie Cellulaire, Université de Parix XI, France |
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Abstract: | Cytoplasmic ribosomal particles were isolated from the ciliated protozoa Tetrahymena pyriformis, the brine shrimp Artemia, and the flagellated alga Euglena gracilis; their stability, density, mass, size and structure in solution have been compared in identical conditions. The small and in particular the large subunits of Euglena ribosomes were less stable than the corresponding particles of the other eukaryotes. Equilibrium centrifugation of the ribosomes of the various species in CsCl density gradients revealed no difference in either their homogeneity or their buoyant density; so no differences were detected in this way in the ratio of their RNA to protein content or in their partial specific volume. Using analytical boundary sedimentation, the sedimentation coefficients s20,w0 of the whole ribosomes were measured to be 81, 81 and 86 S, respectively. Photon correlation spectroscopy of laser light scattered by the whole ribosomes has yielded values for their diffusion coeffcient D20,w0) of 1.51, 1.42 and 1.29 × 10−7 cm2 s−1, respectively; this corresponds to values for their hydrodynamic radius of 142, 151 and 166 Å, respectively. The data indicate also that the solvation of the ribosomes increases with their size and mass.So evidence has been obtained for differences in the size of various eukaryotic ribosomes, and even in the degree of compactness of their structure in solution. |
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Keywords: | Nucleic acids ribosomes structure eukaryotes photon correlation spectroscopy |
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