Cooperative binding of effectors by an allosteric ribozyme.
An allosteric ribozyme that requires two different effectors to induce catalysis was created using modular rational design. This ribozyme construct comprises five conjoined RNA modules that operate in concert as an obligate FMN- and theophylline-dependent molecular switch. When both effectors are present, this 'binary' RNA switch self-cleaves with a rate enhancement of approximately 300-fold over the rate observed in the absence of effectors. Kinetic and structural studies implicate a switching mechanism wherein FMN binding induces formation of the active ribozyme conformation. However, the binding site for FMN is rendered inactive unless theophylline first binds to its corresponding site and reorganizes the RNA structure. This example of cooperative binding between allosteric effectors reveals a level of structural and functional complexity for RNA that is similar to that observed with allosteric proteins.
Department of Molecular, Cellular and Developmental Biology, KBT 452, Yale University, PO Box 208103, New Haven, CT 06520-8103, USA.
A M
AM
Jose
G A
GA
Soukup
R R
RR
Breaker
D001483:Base Sequence; D001665:Binding Sites; D005486:Flavin Mononucleotide / Q000378:metabolism; D007700:Kinetics; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009841:Oligonucleotides / Q000235:genetics; D012313:RNA / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016337:RNA, Catalytic / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D013806:Theophylline / Q000378:metabolism
D009841:Oligonucleotides; D016337:RNA, Catalytic; D012313:RNA; D005486:Flavin Mononucleotide; D013806:Theophylline