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Mitochondrial ribosome assembly in neuro- spora crassa. Chloramphenicol inhibits the maturation of small ribosomal subunits (1977).
| Content Provider | CiteSeerX |
|---|---|
| Author | Lapolla, Robert J. Lambowitz, Alan M. |
| Abstract | ABSTRACT In Neurospora, one protein associated with the mitochondrial small ribosomal subunit (S-5, Mr 52,000) is synthesized intramitochondrially and is assumed to be encoded by mtDNA. When mitochondrial protein synthesis is inhibited, either by chloramphenicol or by mutation, cells accumulate incomplete mitochondrial small subunits (CAP-30S and INC-30S particles) that are deficient in S-5 and several other proteins. To gain additional insight into the role of S-5 in mitochondrial ribosome assembly, the structures of Neurospora mitochondrial ribosomal subunits, CAP-30S particles, and INC-30S particles were analyzed by equilibrium centrifugation in CsCI gradients containing different concentrations of Mg+2. The results show (a) that S-5 is tightly associated with small ribosomal subunits, as judged by the fact that it is among the last proteins to be dissociated in CsCI gradients as the Mg +2 concentration is decreased, and (b) that CAP-30S and INC-30S particles, which are deficient in S-5, contain at most 12 proteins that are bound as tightly as in mature small subunits. The CAP-30S particles isolated from sucrose gradients contain a number of proteins that appear to be loosely bound, as judged by dissociation of these proteins in CsCI gradients under conditions in which they remain associated with mature small subunits. The results suggest that S-S is required for the |
| File Format | |
| Publisher Date | 1977-01-01 |
| Access Restriction | Open |
| Subject Keyword | Small Ribosomal Subunit Mitochondrial Ribosome Assembly Neuro Spora Crassa Inc-30s Particle Csci Gradient Cap-30s Particle Mature Small Subunit Mitochondrial Protein Synthesis Equilibrium Centrifugation Mitochondrial Small Ribosomal Subunit Additional Insight Last Protein Sucrose Gradient Several Protein Different Concentration Neurospora Mitochondrial Ribosomal Subunit Incomplete Mitochondrial Small Subunit |
| Content Type | Text |
