Title: The Most Potent Snow Makers

Abstract: 

Several species of bacteria, fungi, lichens, and insects have evolved proteins that are exceptionally potent ice nucleators. Bacteria and fungi can become aerosolized and lifted into clouds, where they contribute to cloud glaciation and precipitation as rain and snow. Some bacterial ice nucleators are so effective that they are routinely used for artificial snow production. Despite the importance of biological ice nucleation for organismal survival and development, as well as for atmospheric processes, we still know relatively little about the sequences and structures of these proteins, the mechanisms by which they promote water crystallization, and what makes them so extraordinary.

This presentation will describe our approach to combining laboratory experiments, theory, numerical and molecular simulations, and protein structure prediction to elucidate how biological ice nucleators work. Our studies reveal that nature employs a strategy shared across organisms from multiple kingdoms—E pluribus unum (out of many, one)—to nucleate ice at temperatures close to 0 °C by assembling ice-nucleating proteins into large, functional aggregates.

Bio: Valeria Molinero is the Jack and Peg Simons Endowed Chair of Theoretical Chemistry and Distinguished Professor at The University of Utah, where she leads the Henry Eyring Center for Theoretical Chemistry. A physical chemist by passion and training, Molinero received her undergraduate degree in Chemistry (1994) and a Ph.D. in Physical Chemistry (1999) from the University of Buenos Aires, before moving to the United States to pursue postdoctoral research at Caltech. Molinero joined the faculty at The University of Utah in 2006, where she has developed a computational and theoretical research program on the interplay between structure, phase transformation and dynamics in materials. A large part of her focus has been on investigating the behavior of water, silica and materials for energy. Molinero has been recognized with multiple awards, including the Helmholtz Award from the International Association of the Properties of Water and Steam, the Beckman Young Investigator Award, the Camille Dreyfus Teacher Scholar Award, the Cozzarelli Prize on Physical and Mathematical Sciences of the Proceedings of the National Academy of Sciences, a Doctor Honoris Causa from the University of Buenos Aires, and the Irving Langmuir Award in Chemical Physics. Molinero is an elected member of the Utah Academy of Engineering and Science, the American Academy of Arts and Sciences, and the National Academy of Sciences of the United States.