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Correlation of the expansion segments in mammalian rRNA with the fine structure of the 80 s ribosome; a cryoelectron microscopic reconstruction of the rabbit reticulocyte ribosome at 21 å resolution
- Source :
- Journal of Molecular Biology. 279:403-421
- Publication Year :
- 1998
- Publisher :
- Elsevier BV, 1998.
-
Abstract
- Samples of 80 S ribosomes from rabbit reticulocytes were subjected to electron cryomicroscopy combined with angular reconstitution. A three-dimensional reconstruction at 21 A resolution was obtained, which was compared with the corresponding (previously published) reconstruction of Escherichia coli 70 S ribosomes carrying tRNAs at the A and P sites. In the region of the intersubunit cavity, the principal features observed in the 70 S ribosome (such as the L1 protuberance, the central protuberance and A site finger in the large subunit) could all be clearly identified in the 80 S particle. On the other hand, significant additional features were observed in the 80 S ribosomes on the solvent sides and lower regions of both subunits. In the case of the small (40 S) subunit, the most prominent additions are two extensions at the base of the particle. By comparing the secondary structure of the rabbit 18 S rRNA with our model for the three-dimensional arrangement of E. coli 16 S rRNA, these two extensions could be correlated with the rabbit expansion segments (each totalling ca 170 bases) in the regions of helix 21, and of helices 8, 9 and 44, respectively. A similar comparison of the secondary structures of mammalian 28 S rRNA and E. coli 23 S rRNA, combined with preliminary modelling studies on the 23 S rRNA within the 50 S subunit, enabled the additional features in the 60 S subunit to be sub-divided into five groups. The first (corresponding to a total of ca 335 extra bases in helices 45, 98 and 101) is located on the solvent side of the 60 S subunit, close to the L7/L12 area. The second (820 bases in helices 25 and 38) is centrally placed on the solvent side of the subunit, whereas the third group (totaling 225 bases in helices 18/19, 27/29, 52 and 54) lies towards the L1 side of the subunit. The fourth feature (80 bases in helices 78 and 79) lies within or close to the L1 protuberance itself, and the fifth (560 bases in helix 63) is located underneath the L1 protuberance on the interface side of the 60 S subunit.
- Subjects :
- Models, Molecular
Reticulocytes
Cryo-electron microscopy
Protein subunit
Molecular Sequence Data
Biology
Ribosome
Species Specificity
Reticulocyte
Structural Biology
RNA, Ribosomal, 16S
RNA, Ribosomal, 28S
Escherichia coli
Image Processing, Computer-Assisted
RNA, Ribosomal, 18S
medicine
Animals
Molecular Biology
Protein secondary structure
Base Sequence
Ribosomal RNA
Microscopy, Electron
RNA, Bacterial
RNA, Ribosomal, 23S
A-site
Crystallography
medicine.anatomical_structure
RNA, Ribosomal
Helix
Nucleic Acid Conformation
Rabbits
Ribosomes
Subjects
Details
- ISSN :
- 00222836
- Volume :
- 279
- Database :
- OpenAIRE
- Journal :
- Journal of Molecular Biology
- Accession number :
- edsair.doi.dedup.....73ee02bbd2c624180c2c6c7bc95e10af