Biophysical Society Bulletin | July/August 2019

Biophysicist in Profile

Carlos Baiz Areas of Research

Institution University of Texas at Austin

Biophysical chemistry of proteins and membranes in complex environments

At-a-Glance

Carlos Baiz traveled to the United States from Uruguay as a high school exchange student, and fell in love with the area of Michigan where he was living. He stayed in the United States for universi- ty, and began working in a lab as an undergraduate. There, he discovered how rewarding research could be, which sent him down the path toward his career as a biophysicist.

Carlos Baiz

Carlos Baiz , Assistant Professor in the Department of Chem- istry at the University of Texas at Austin, grew up in Salto, Uruguay, a small town near the northern border with Brazil and across the river from Argentina. He always liked taking things apart and exploring how things worked. “In high school, I became seriously interested in chemistry,” he says. “The book that really got me thinking about studying chemistry was General Chemistry by Linus Pauling . I had picked up this book at a bookstore on impulse and ended up reading it cover to cover.” He traveled to the United States as an exchange student in 2001 for his final year of high school, to learn English and experience the culture. He lived with a host family in Calumet, Michigan, a small town in the state’s Upper Peninsula. “I really liked the area and my host family, so after graduating, I decid- ed to stay and attend Michigan Technological University as an undergraduate,” he shares. As a young person, Baiz says, “I never had a strong sense of what career I wanted to pursue, all I knew is that I liked phys- ics and chemistry. I wanted to learn more about how mole- cules behaved, and how chemical structures translate to bulk material properties. When I joined a lab as an undergraduate, I discovered how rewarding scientific research can be.” He received his bachelor of science degree in chemistry from Michigan Technological University in 2005, then undertook a PhD program at the University of Michigan-Ann Arbor, where he worked with Kevin Kubarych . Following the completion of his PhD, he joined Andrei Tokmakoff’s group at MIT, where he began using infrared (IR) spectroscopy to study protein folding. “During my postdoc, the group moved from MIT to the University of Chicago,” he shares. “I was very involved with the move. Helping set up the new labs in Chicago was a valuable experience and helped me understand the intricacies of setting up laser labs from scratch. The experience trans- lated very well when setting up my own labs at University of Texas-Austin.”

As a postdoc, he explored fast protein folding using tempera- ture-jump two-dimensional infrared spectroscopy. “Infrared spectroscopy probes the vibrational modes of the protein backbone, which report directly on the secondary structure of the protein. However, the spectra are congested and some- what difficult to interpret,” he explains. “We were fortunate to collaborate with Prof. Vijay Pande on simulations. The MD [molecular dynamics] simulations were essential for help- ing us understand how the protein folds. I also worked on developing simulation methods to interpret IR spectra of large proteins. The efforts were mostly directed at making 2D IR spectroscopy a more useful biophysical tool.” Following his postdoc, Baiz started a position as assistant professor in the chemistry department at the University of Texas at Austin. His group is investigating proteins and lipid membranes using IR spectroscopy. “Specifically, we inves- tigate the environments surrounding biomolecules using ultrafast infrared spectroscopy. In general, we are interest- ed in complex, crowded environments that mimic the cell cytoplasm. Much of the protein folding work that was done in the past, starting with the Anfinsen experiments, has been on biomolecules in dilute buffer solutions, but recently it has become evident that the environment plays a significant role in determining the structure and the dynamics of proteins,” he shares. “We are also investigating ‘cryoprotectants,’ which are small molecules that are typically added to cells prior to freezing them. Freezing single cells is possible, but with larger tissues, ice crystals mechanically damage the cells and tissue structure. Cryoprotectants are compounds that cause water to freeze in a disordered ‘glassy’ state. These compounds, however, are toxic to cells at the concentrations required for freezing large tissues. For this reason, we are investigating their effects on protein and membrane structure and stability. Understanding the effects of these compounds on biomole- cules will enable us to develop formulations that have lower toxicity.”

July/August 2019

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