Nat Struct Mol Biol 14(12) 1189-1195 (2007)

[DOI Link]

Substrate RNA positioning in the archaeal H/ACA ribonucleoprotein

Department of Chemistry and Biochemistry, Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida 32306; Departments fo Biochemistry & Molecular Biology, Universtiy of Georgia, Athens, GA 30602.

The most complex RNA pseudouridylases are H/ACA ribonucleoprotein particles, which use a guide RNA for substrate capture and four proteins (Cbf5, Nop10, Gar1 and L7Ae/NHP2) for substrate modification. Here we report the three-dimensional structure of a catalytically deficient archaeal enzyme complex (including the guide RNA and three of the four essential proteins) bound to a substrate RNA. Extensive interactions of Cbf5 with one guide-substrate helix and a guide RNA stem shape the forked guide-substrate RNA complex structure and position the substrate in proximity of the Cbf5 catalytic center. Our structural and complementary fluorescence analyses also indicate that precise placement of the target uridine at the active site requires a conformation of the guide-substrate RNA duplex that is brought about by the previously identified concurrent interaction of the guide RNA with L7Ae and a composite Cbf5-Nop10 surface, and further identify a residue that is critical in this process.

PMID:18059286 [PubMed - indexed for MEDLINE]

This publication is one of the several that describes a structure solved either at the Kasha Laboratory, Institute of Molecular Biophysics or in collaboration with the Institute Faculty. The data used for this structure determination came in full or part from the Macromolecular X-Ray Crystallography Facility.