Vincent LiCata on Proteins with Superpowers
Dr. Vincent LiCata, Louis S. Flowers Professor in the LSU Department of Biological Sciences, talks about his biochemistry research and gives us insight on how to get into biology on this inaugural Experimental (formerly Benchtop Talks) episode.
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[0:00] This is Experimental, where we explore exciting research occurring at Louisiana State University and learn about the individuals posing the questions. I'm Becky Carmichael and today we will hear from Dr. Vincent LiCata from the Department of Biological Sciences about proteins with superpowers.
[0:20] Did you know that there are organisms that can live near the boiling point of water in hot springs or on the ocean floor? And what if I told you that there are organisms that can survive doses of radiation thousands of times higher than what would kill a human being? Or have you ever heard of organisms that live below the freezing point of pure water? They live inside veins in the ice floating on Arctic seas. Now my lab at LSU studies proteins from all these types of organisms. Organisms like these are called extremophiles and their proteins are called extremophilic proteins. Proteins perform almost all the chemical and physical work inside living cells. And my lab wants to figure out how these extremophilic proteins work under such extreme conditions. Conditions that would destroy or disable most human proteins. Many of the proteins that we study in my lab are DNA binding proteins. We want to know how these proteins attached to DNA, how they regulate it, turn it on and off, or repair it or replicate it under such extreme conditions. For example, one of our recently published studies from a fresh graduate of a lab, named Jacob Warfel, looked at a protein called Recombinase A, or Rec A for short. Rec A helps repair DNA that's been damaged, such as when radiation fractures DNA. We found that the Rec A protein from a radiation resistant organism binds to DNA up to 20 times tighter than the Rec A from an organism that's killed by radiation. So this means that the Rec A from the radiation resistant organism will be 20 times more able to get to and repair damaged DNA than the Rec A from an organism like you or me. What we'd like to know next is how to change a normal Rec A protein into a super radiation resistant Rec A protein. And that's a research question that we're investigating right now here at LSU. Another protein that we work on is called taq polymerase. Taq, T-A-Q, it's a celebrity enzyme. Not only is it the subject of a Nobel Prize, but sales of Taq are currently a billion dollar worldwide industry. And that's because Taq is used in a process that's called the polymerase chain reaction, or PCR for short. PCR is used to amplify DNA at crime scenes to detect foreign DNA and infections and diseases, and to replicate and to clone genes. But my lab is most interested in how Taq polymerase survives being in boiling water for long periods of time, when boiling water would destroy almost every single protein in your or my body. And what we found so far, which we're still trying to understand, is that when Taq folds up into its organized, active three dimensional structure, it does this with much less loss of entropy than when other proteins fold up into their active structures. Now, entropy is one of the most important forces in the universe. And one way to think about entropy is that it's the natural favorability of disorder. So for example, it takes energy to organize your room. But entropy pushes everything towards disorder. So anytime anything becomes highly organized like a protein, or your room, an entropic penalty is paid for it to stay organized. So what we found with Taq, is that it pays a much lower entropic penalty to stay organized than other similar proteins that are not resistant to boiling water or high heat. This lower entropic penalty makes Taq super stable. It would be like if suddenly it was three times easier to clean your room. Your room would stay a lot cleaner. But how does tak get away with paying an entropic penalty that's three times lower than similar proteins have to pay? Well, that's another thing we'll be working on in my lab for the next few years.
[4:59] How did you get into the sciences in the first place, though? Before the lab and the research and being a professor and all that? Like think about when you were really getting interested in the sciences whenever that was.
[5:11] Yeah, I don't know. I mean, because I read all these stories now since there's so many science bloggers and science journalists. You see all these origin stories about scientists who "I knew I wanted to be a scientist the first time I saw this frog jump on the windshield of the car" or "the first time I saw a shooting star". And I've never really thought about what my origin story is. I think...
[5:35] Nothing has to be so clean cut as an origin story.
[5:37] I don't think it was punk Tate like that. It was just sort of like, yeah, science was something I was interested in and could do. I worked in a lab, even in high school. I actually worked in a lab at University of Florida. And it was really fun. I mean, science is really fun. It's like this amazing puzzle that you try and solve every day when you work on it.
[5:59] So now you're still doing biochemistry. When you became a professor, what got you into the research that you do in your lab?
[6:06] Well, I kind of find it fascinating. One of the things I find fascinating is the stuff that we use in clinical applications or drugs that are not really understood very well. So for example, there's about 3000 drugs on the market in the United States. And we understand how maybe 500 of them work, maybe 1000. Some of them we just know they work but there's some of you don't even know what protein they bind to or anything and I find that fascinating and there's a whole big, you know, world of research you can do on those proteins.
[6:44] Experimental was recorded and produced in the KLSU Studios here on the campus of Louisiana State University and is supported by LSU's communication across the curriculum and the College of Science. Today's interview was conducted by Mark DiTusa and edited by Bailey Wilder. To learn more about today this episode, subscribe to the podcast, ask questions, and recommend future investigators, visit cxc.lsu.edu/experimental