BS, ., 1953
MS, Washington State University, 1956
PhD, California Institute of Technology, 1961
NSF Postdoctoral Fellow, Yale University Medical School (1961-2); USPHS Postdoctoral Fellow, University of Kentucky Medical School (1963-4; Fogarty Senior International Fellow (1983)
Biochemical mechanisms involved in the synthesis of polypeptides and their folding on ribosomes
The best known work from my laboratory is on development of cell-free systems for the synthesis of proteins and on the biochemical mechanisms involved in their ribosomal synthesis. The results have contributed to the current understanding of the chemical mechanisms by which mRNA and tRNA are moved through the ribosome and how peptide bonds are formed during the elongation of a nascent peptide. Techniques involving fluorescence have been used extensively. New procedures have been developed to adapt these techniques to the ribosomal system. Fluorescent probes have been covalently attached to specific sites in ribosomes or tRNA, then fluorescence is used to monitor changes in the conformation or position of the probes that occur during the reaction of peptide elongation.
The current focus of the laboratory is on folding of proteins as they are synthesized. Special interest is placed on the role of the ribosome in this process. N-fluorophore-methionine from bacterial initiator tRNA is cotranslationally incorporated at the N-terminal position of a nascent peptide, then followed by fluorescence as the peptide is extended. Recent results lead to the conclusion that folding occurs as amino acids are added sequentially to the C terminus of a nascent peptide while it exists as peptidyl-tRNA on the ribosome.
"Expression of different coding sequences in cell-free bacterial and eukaryotic systems indicates translational pausing on Escherichia coli ribosomes" FEBS Lett. 482 (2000): 185-188.
"Fluorophores at the N terminus of nascent chloramphenicol acetyl transferase peptides affect translation and movement through the ribosome" J. Biol. Chem. 275 (2000): 1781-6.
"The effect of a hydrophobic N-terminal probe on translational pausing of chloramphenicol acetyl transferase and rhodanese" J. Mol. Biol. 286 (1999): 71-81.
"Cotranslational folding" Current Opinion in Structural Biology 9 (1999): 111-114.