Thermal stability of turnip yellow mosaic virus RNA: effect of pH and multivalent cations on RNA deaggregation and degradation
| Autor: | Tom Sam, Cornelis Pley, Gert-Jan Eecen, Michel Mandel, Leendert Bosch |
|---|---|
| Rok vydání: | 1991 |
| Předmět: |
Electrophoresis
Light Cations Divalent Biophysics Biochemistry Virus Divalent Mosaic Viruses Structural Biology Centrifugation Density Gradient Polyamines Genetics Scattering Radiation chemistry.chemical_classification Gel electrophoresis Differential centrifugation Molar mass Turnip yellow mosaic virus biology Temperature RNA Hydrogen-Ion Concentration Ribosomal RNA biology.organism_classification Kinetics chemistry Spectrophotometry RNA Viral |
| Zdroj: | Biochimica et Biophysica Acta (BBA) - Gene Structure and Expression. 1129:64-72 |
| ISSN: | 0167-4781 |
| Popis: | Light scattering studies of RNA isolated from turnip yellow mosaic virus (TYMV) revealed a molar mass of 1.9.10(6) g mol-1, which is close to the value of 2.0.10(6) g mol-1 published for intact genomic TYMV RNA (2M RNA). However, gel electrophoresis under denaturing conditions demonstrated that only 30-40% of this native RNA was 2M RNA. Sucrose gradient centrifugation revealed the occurrence of a series of smaller RNA size classes, the mass ratios of which were greatly influenced by the pH of the solution and the presence of EDTA. These results suggest that native TYMV RNA preparations originally contain a mixture of intact RNA particles and of aggregates of RNA fragments with the same molar mass of about 2.10(6) g mol-1, and that the size classes are intermediates in the deaggregation process of the degraded genomic TYMV RNA. The native RNA displayed pH-dependent deaggregation and degradation. The degradation process of 2M RNA followed (pseudo) first-order kinetics. Lower degradation rates were observed for RNA depleted of divalent cations and polyamines. For depleted 2M RNA an enthalpy of activation of about 100 kJ mol-1 and an almost zero entropy of activation was calculated. Similar values were also found for depleted E. coli ribosomal RNAs and depleted MS2 RNA, demonstrating that all RNAs are equally vulnerable to degradation. In the presence of multivalent cations the activation enthalpy for 2M TYMV RNA degradation increased to 150 kJ mol-1 and the entropy of activation to 150 J K-1 mol-1, indicative for a different degradation mechanism. |
| Databáze: | OpenAIRE |
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