Notes 20100504 Ribozyme Guest Lecture
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Contents |
IBMB, Ribozymes
- Dr. Richard Collins
- interdiscipline science
- RNA biology-- things that RNA can do that proteins can't
- 1960: mRNA, rRNA, tRNA
- snRNA, snoRNAs, ribozymes, telomerase
- imprinting, x-chromosome inactivation
- RNA sequence editing after transcription (tissue, gene specific)
- RNA localization, structure
- tmRNA, 6S RNA, 7SK RNA, sRNA, riboswitches
- miRNA, siRNA
- -- newer stuff exists (above list is two years old)
- riboswitch: two or more structural conformations
Ribozymes
- an excellent model system for RNA structure, function
- viroid infection, tomato plants; a viroid is a small circular stretch of RNA, does not particularly code for a protein, causes disease
- Neurospora (filamentous fungus) bread mold, model system
- 1940: one gene = one protein -- Neurospora
- VS RNA in mitochondria of Neurospora
Multimeric VS DNA plasmid
- Varkud satelite (VS)
- VS RNA is a multimeric transcript
- part of this RNA performs self cleavage
- the ribozyme is then capable of self-ligation
- a different plasmid has a reverse transcriptase which converts the VS RNA loop back into a VS DNA plasmid
- the question is which part of the VS RNA is responsible for which function
- packing in solution allows the RNA to cleave; brings active site of ribozyme to target
Studying RNA structure
- X-ray crystallography and NMR spectoscopy -- not completed with VS RNA (no successful crystals yet)
- FRET, cross-linking, mutation, chemical modification: have been done on VS RNA
- consider the chemical modifications as a fine-grained mutation
- functional study: does not require anything extra in solution as the substrate is the ribozyme
