Structural Studies of Riboswitches
EMSL Project ID
10190
Abstract
Riboswitches are metabolite-binding domains in certain messenger RNAs that modulate gene expression in response to changing concentrations of metabolites. Riboswitches are composed of two functional and sometimes distinct structural domains. One domain acts as a natural aptamer that binds the target metabolite with high specificity and affinity. The other domain is an ?expression platform? that controls expression of adjacent genes or operons as a consequence of allosteric changes in the noncoding region of the mRNA that are brought about as a result of aptamer-ligand complex formation. There are seven known riboswitches that bind various metabolites including coenzyme B12, thiamin pyrophosphate (TPP), flavin mononucleotide (FMN), S-adenosyl methionine (SAM), lysine, adenine and guanine. The adenine and guanine riboswitches have the smallest aptamers at about 100 nucleotides. Biochemical studies of the guanine aptamer suggest numerous productive contacts that engulf the metabolite entirely within the aptamer. However, there is currently no understanding of the structural details of the free aptamer and how its structure changes, precipitating an allosteric change in the structure of the riboswitch that then leads to modulation of gene expression. This proposal will be directed at using solution-state NMR methods to solve the structure of the guanine riboswitch aptamer, both free, and bound to the guanine metabolite.
Project Details
Project type
Capability Research
Start Date
2004-12-29
End Date
2005-10-03
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members