The theory of evolution suggests that present-day organisms evolved from earlier life forms.
At the molecular level, evolution reshaped some of the enzymes that help complete chemical processessuch as converting food into energyin humans and all other life forms.
Now a University of Iowa researcher and his colleagues describe the evolution of various forms of the enzyme "dihydrofolate reductase" as it occurred from bacteria to humans. Their paper, "Preservation of Protein Dynamics in Dihydrofolate Reductase Evolution," appears in the Dec. 13 issue of the Journal of Biological Chemistry.
Amnon Kohen, professor of chemistry in the UI College of Liberal Arts and Sciences and member of the Interdisciplinary Program in Molecular and Cellular Biology, and his collaborators used bioinformatics (genetic sequencing information), computer-based calculations, artificial mutagenesis (DNA modification), and kinetic measurements in their work. They studied "humanized" forms of an enzyme that originated with the common bacterium E. coli in order to relate the action of protein dynamics and catalysis to the process of enzyme evolution.
They found that enzyme dynamics evolved over millions of years to optimize a specific catalyzed reaction that occurs in humans.
"Enzymes are critical components of every living cell, and they catalyze almost all chemical reaction in life. We study how evolution occurred on the molecular level," Kohen says. "This study is an attempt to understand how evolution of the whole organism (for example from bacteria like E. coli to humans) is expressed on the molecular level.
"We chose a 'housekeeping' enzyme, which is present in almost all organisms and is critical to life. That enzyme is called dihydrofolate reductase and is involved in DNA biosynthesis and all cells' replication," he says.
He says the researchers "bridged" between the bacterial and human enzymes by pro
|Contact: Gary Galluzzo|
University of Iowa