Celeste Probart
Contributing Writer
National Chemistry week, the week of Oct. 23, marks the chemistry department’s annual Helen Murray Free lecture series. This year’s speaker was Catherine Drennan, a biochemist from the Massachusetts Institute of Technology and the Howard Hughes Medical Institute. Drennan began her journey as a high school science and drama teacher. She remains passionate about education to this day with many of her teaching materials being free and accessible online.
The 11 a.m. technical lecture titled, “Revealing the secrets of metalloenzymes one snapshot at a time,” focused on how ribonucleotide reductases (RNR) can be targeted. RNR are a rate limiting step in DNA synthesis, and a key regulator. Historically, RNRs have been targets utilized in cancer pharmaceuticals and anti-HIV medications. Drenner emphasized the important work of RNR saying, “I wanted to convince you all that RNR does not stand for ‘rest and relaxation.’ These are very hardworking enzymes and they do a lot of moving.”
Drennan’s exploration of RNR is driven by growing antibiotic resistance. Antibiotic resistance is an extreme issue due to excessive use of antibiotics combined with antibiotic pollution. These two factors allow for bacterial species to gain resistance to the antibiotic drugs. It also creates a shortage of what antibiotics are effective, meaning that there will be more deaths due to infection every year because of this resistance.
Drennan introduced E. coli RNR, which had little work on its structure since the 1990s. The ring structure was determined with the help of her lab group. She compared E. coli RNR with the structure of human RNR, which had a few key differences, including a smaller ring so the activating group cannot fit through the center of the ring. This is important to consider when developing antibiotic drugs.
In her evening public lecture, “Exploring the Molecular World” Drennan described her journey into professorhood. As a child, she was diagnosed with severe dyslexia. Due to this, Drennan learned how to read by memorizing shapes. The biophysical techniques that are used in Drennan’s lab group require matching known small molecules to the shapes that are generated. These shapes can be more blurry or clear based on the resolution and quality. Since she had learned to read by memorizing shapes, she applies this skill to the techniques that are utilized in her lab. Drennan’s experiences resonated with students, including Braelynn Sexton ’30 who said, “I find things like this very interesting. I am also dyslexic, so I wanted to hear kind of her voice about dyslexia and her experience.”
The lecture further explores these biophysical techniques. The techniques that were discussed were X-Ray crystallography and cryogenic electron microscopy (cryo EM). Recently, cryo EM underwent a “resolution revolution” allowing the protein to have multiple photos or ‘snapshots’ taken of it. Before this, X-Ray crystallography was the best option; however, it took limited snapshots, and took a much longer time to complete.
Drennan ended her lecture by encouraging students to pursue STEM regardless of the backlash they may face. She further encouraged students that have a seat at the table (a place in STEM) to help others get one. Increasing diversity in STEM helps to increase perspectives and can bring more ideas to solving problems.
Attendants appreciated Drennan’s lectures and hearing about her work. Aria Weaver ’29 said, “When I think of.… a chem lab or a biochem lab…. I’m always working by myself. So it was super cool to see just how many people…. are interacting with each other and how much research they’re pulling on to make this possible.”
