GROUP I RIBOZYME P4-P6 DOMAIN FROM TETRAHYMENA

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Group I introns ¿¿¿¿¿or ribozymes¿¿¿¿¿ are independently folded RNA molecules that can self-splice from a messenger RNA (mRNA) prior to translation. More than 2000 sequences of group I introns have been identified since their discovery ~25 years ago. These ribozymes were classified into different subgroups based on sequence and secondary structure conservation. The first crystal structure of a domain (160 nucleotides; non-catalytic) from a group I ribozyme from the ciliate Tetrahymena thermophila was obtained in 1996. Improved resolutions were obtained in 2001 for a mutant containing a single nucleotide change. In this project, we first obtained crystals of a complex between the P4-P6 domain and a specifically bound ligand. Our hope is that a structure of that complex at high resolution would facilitate our understanding of the molecular recognition between a small molecule and its RNA target. Second, we further mutated the original RNA construct in order to seek for further improvement of resolution. These constructs are being currently screened for crystallization. This approach could offer general guidelines for the future design of RNA constructs for crystallography.