Barbara Golden

Active Mentor - currently hosting PULSe students for laboratory rotations and recruiting PULSe students into the laboratory; serves on preliminary exam committees

Current Research Interests:

The focus of our research is the structure and folding of catalytic RNAs. Unlike proteins, RNAs have a highly charged backbone, only 4 different monomeric units (compared to the 20 amino acids that make up proteins) and functional groups that are largely sequestered within the majorand minor grooves of the double helix. Yet, in the presence of magnesium ion, many RNA molecules have stable, globular, tertiary structures that support biological catalysis. To understand how these molecules fold and function, we are investigating RNA structures by X-ray crystallography. Our research is concentrated on RNA enzymes, or ribozymes, that display catalytic activity in the complete absence of protein cofactors.

Group I introns catalyze transesterification reactions by activating a guanosine nucleophile for attack on the phosphodiester backbone. The structure of an active ribozyme derived from the catalytic core of the Tetrahymena LSU group I intron was recently solved at 5 Å resolution. This structure reveals extensive interactions between two domains that construct an active site composed of RNA. These studies will be extended to obtain a higher resolution picture of a group I intron and examine the intron's interaction with its substrates.

A second RNA enzyme, RNase P also catalyzes phosphodiester cleavage. In contrast to the Tetrahymena ribozyme, RNase P uses water as the nucleophile. The other substrate for the reaction is a precursor tRNA, cleaved by the enzyme after the 5' leader sequence to generate a mature tRNA. RNase P from Bacillus subtilis consists of a 14 kD protein and the 405 nucleotide P RNA. We are using X-ray crystallography to investigate the active site of this enzyme.

Selected Publications:

Golden, B.L., Kim, H., and Chase, E. Crystal structure of a phage Twort ribozyme-product complex. Nature Structural and Molecular Biology. 12:82-89 (2005).

Linger, B.R., Kunovska, L., Kuhn, R.J. and Golden, B.L. Sindbis viurs nucleocapsid assembly: RNA folding promotes capsid protein dimerization. RNA 10:128-138 (2004).

Golden, B. L., Gooding, A. R., Podell, E. R., and Cech, T. R. A Preorganized Active Site in the Crystal Structure of the Tetrahymena Ribozyme. Science. 282:259-264 (1998).

Golden, B. L., and Cech, T. R. Conformational switches involved in orchestrating the successive steps of group I RNA splicing. Biochemistry 35:3754-3763 (1996).