Atomic-Level Motion in Proteins May Drive Bacteria’s Ability to Evade Immune System Defenses

A study from Indiana University (IU) has found evidence that extremely small changes in how atoms move in bacterial proteins can play a big role in how these microorganisms function and evolve. The research, recently published online on March 27, 2017 in PNAS, is a major departure from prevailing views about the evolution of new functions in organisms, which regarded a protein's shape, or "structure," as the most important factor in controlling its activity. The PNAS article is titled “Entropy Redistribution Controls Allostery in a Metalloregulatory Protein.” "This study gives us a significant answer to the following question: How do different organisms evolve different functions with proteins whose structures all look essentially the same?" said Dr. David Giedroc (photo), Lilly Chemistry Alumni Professor in the IU Bloomington College of Arts and Sciences' Department of Chemistry, who is senior author on the study. "We've found evidence that atomic motions in proteins play a major role in impacting their function." The study also provides new insights into how microorganisms respond to their host's efforts to limit bacterial infection. Serious bacterial infections in people include severe health-care-associated infections and tuberculosis, both of which have grown increasingly common over the past decade due to rising drug resistance in bacteria. Approximately 480,000 people worldwide develop multidrug-resistant (MDR) tuberculosis each year, for example, according to the Centers for Disease Control and Prevention (CDC). "What we've shown is atomic-level motional disorder -- or entropy -- can impact gene transcription to affect the function of proteins in major ways, and that these motions can be 'tuned' evolutionarily," said Dr. Daiana A. Capdevila, a postdoctoral researcher in Dr. Giedroc's lab, who is first author on the study.
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