NSF Award
2311258
With the support of the Chemistry of Life Processes Program in the Chemistry Division, Professor Catherine Royer of Rensselaer Polytechnic Institute will investigate enzymes from organisms living in deep sea environments. After long being considered devoid of life, it has become clear that the Earth’s deep biosphere is home to an enormous diversity of life. In fact, the deep oceans and the continental and oceanic crusts are thought to contain ~90% of the Earth’s microbial biomass. Viruses and bacteriophages are present in the oceans at ~15-fold higher abundance than microbes. They contribute to the death of ~20% of all oceanic microbes every day, releasing up to 145 gigatons of carbon annually, including massive amounts of deoxyribonucleic acid (DNA). The enzymes being targeted in this work, Dnases, break up DNA polymers. Understanding the differences between these enzymes from the deep sea and those from surface bacteria is expected to provide insight into how sequence and evolution tune function and may yield new enzymes for biotechnological applications. As part of the broader impacts of these studies, students from high school to undergraduate and graduate levels will be trained in structural genomics and biophysics via online and laboratory experiences. <br/><br/>Large numbers of marine microbes exhibit extracellular Dnase (exNuc) activity, underscoring the importance of these enzymes in oceanic biofilm dynamics and geobiochemical cycling. Recent progress combining advances in experimental approaches with increasingly powerful computational tools has revealed the central role of dynamics in regulating biochemical activity, and the modulation of these states by amino acid sequence and reaction conditions. The single common physical parameter in deep ocean environments is high pressure. It has long been known that biomolecules from surface organisms are not functional under the extreme conditions of the deep biosphere. The present work will combine experimental and computational biophysics approaches coupled with high pressure (NMR, fluorescence, X-ray diffraction, small angle X-ray scattering (SAXS) and molecular modeling) to address the fundamental question of how these exonuclease sequences have evolved to maintain function under extreme conditions of high pressure and of high and low temperature.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
