A team of University of Maryland scientists have made a discovery that will help better direct drug therapies to their molecular targets.

As reported in the June 13 issue of the online journal PLoS ONE, the researchers, led by Jonathan Dinman, assistant professor of cell biology and molecular genetics at the University of Maryland, have found the difference between two closely related components in the messenger RNA (mRNA) near-cognate and non-cognate codons terms that have long been used, but not understood.

Although these two terms have been used by scientists for over 40 years, the differences between them have never been properly defined. Here, we have made this determination at both the molecular and mechanistic levels, and developed a simple drug-based test to differentiate them. Its a real step in designing the pathway of rational drug design.

Defining the Codons

Messenger RNA tells the ribosome what kind of proteins to make and how much to crank out. The codons specify which amino acids should end up in the protein, says Dinman. If the wrong codon is selected, the wrong amino acid ends up in the protein, which can alter or destroy the function of that protein and cause human disease.

Codons are the three-part packets of information in DNA that specify amino acids. They are read by corresponding packets in aminoacyl tRNAs (aa-tRNA) called anticodons. Codons are among the many components that James Watson, Francis Crick, Franois Jacob, Jacques Monod, Marshall Nirenberg and others found in their discoveries of DNA and genetic code in the late 1950s and early 1960s.

Crick coined the terms near-cognate and non-cognate codons but he didnt really define the difference, says Dinman. In fact, no one really ever has defined them, until now. Its been fuzzy.

Cognate tRNAs properly decode genetic information in mRNAs, while near- and non-cognate tRNAs correspond to close but no cigar and fuggedab
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Contact: Ellen Ternes
eternes@umd.edu
301-405-4627
Public Library of Science
12-Jun-2007