B.S., University of Wisconsin
Ph.D.,University of California, San Diego
Aminoacylation of tRNA; expansion of the genetic code; Charcot-Marie-Tooth disorder; enzyme catalysis; protein engineering
Dr. First's major research interests include aminoacylation of tRNA, protein-nucleic acid interactions, enzyme catalysis, nuclear translocation, and apoptosis.
Aminoacyl-tRNA synthetases catalyze the attachment of amino acids to their cognate tRNAs. This reaction occurs by a two-step mechanism in which the amino acid is first activated and then transferred to the 3 prime end of the cognate tRNA. Misacylation of tRNA with the wrong amino acid occurs less than one time for every 10,000 rounds of catalysis the enzyme performs. Our research focuses on two areas related to aminoacyl-tRNA synthetases.First, we are developing methods to expand the genetic code to include D-amino acids. Current efforts are aimed at engineering orthogonal tyrosyl-tRNA synthetase variants that are specific for either D- or L-tyrosine. Second, we are investigating the role that the tyrosyl-tRNA synthetase plays in Charcot-Marie-Tooth disorder. Charcot-Marie-Tooth disorder is the most common inherited peripheral neuropathy, affecting 150,000 individuals in the U.S. Patients experience a degeneration of their peripheral nerve cells, leading to atrophy of the muscles controlling their hands, feet, forearms, and lower legs. Ultimately, this leads to loss of the ability to perform routine tasks, such as holding a pencil or turning a door knob. Mutations in the gene encoding tyrosyl-tRNA synthetase are responsible for Dominant Intermediate Charcot-Marie-Tooth disorder (DI-CMTC). Our research suggests that DI-CMTC may be due to a defect in the fidelity of tyrosyl-tRNA synthetase. We are currently testing the hypothesis that mutations the gene encoding tyrosyl-tRNA synthetase lead to misincorporation of amino acids during protein synthesis and an increase in protein misfolding.
All Publications: PubMed