Christine Hagan
Associate Professor of Chemistry, Co-Director of Biochemistry Program
Biography
Teaching
I teach courses in general chemistry (CHEM 181 & CHEM 231) and biochemistry (CHEM 301). In each of these courses, I aim to help my students develop an appreciation for the logic of chemistry. With a deep understanding of a few fundamental concepts, we can explain many complex processes that occur in the natural world and also imagine ways to solve problems using chemical tools. I have also taught a course in Holy Cross’s Passport Program (Intro to Biochemistry: A Case Study in Bacterial Warfare). This course provided an integrated introduction to chemistry and biology, and students in the course engaged in an original research project related to my lab’s work on bacterial contact-dependent inhibition systems. I am passionate about providing undergraduates with substantive research experiences as such experiences were crucial in my own development as a scientist.
Research
My research group is currently focused on understanding how bacteria kill one another using small protein toxins. Specifically, we are studying a mechanism of interbacterial competition in Gram-negative bacteria called contact-dependent inhibition (CDI). The Gram-negative class of bacteria includes many human pathogens such as E. coli, K. pneumoniae, A. baumannii, and P. aeruginosa. These organisms are inherently resistant to many antibiotics because their cells are surrounded by two membranes. The outer membrane possesses chemical properties that make it impermeable to many molecules, including antibiotics. CDI systems, however, efficiently deliver their protein toxins through the outer membrane. We are developing biochemical tools to dissect the CDI toxin delivery mechanism. By understanding how CDI toxins overcome the outer membrane barrier, we hope to identify ways of designing better antibiotics that can do the same.
Students who are interested in joining the Hagan Lab should apply through the chemistry department’s group joining process, which occurs at the beginning of the spring semester each year. Students typically apply in the spring of their sophomore year and join the group the following summer or fall.
Selected Publications
(Undergraduate authors are listed with an asterisk.)
A. K. Y. Tiu*, G. C. Conroy*, C. E. Bobst, C. L. Hagan. Autoproteolytic Mechanism of Toxin Release from a Contact-Dependent Inhibition Protein. Journal of Bacteriology. 206, e00249-24 (2024).
E. M. Bouzan*, C. L. Hagan. Site-specific photocrosslinking to investigate toxin delivery mediated by the bacterial β-barrel assembly machine. In: Ieva, R. (Ed.) Transmembrane β-barrel Proteins. Methods in Molecular Biology, 2778, 117-131 (2024). Humana, New York, NY.
C. L. Curley*, T. P. Fedrigoni*, E. M. Flaherty*, C. J. Woodilla*, C. L. Hagan. Bacterial contact-dependent inhibition protein binds near the open lateral gate in BamA prior to toxin translocation. Biochemistry. 60, 2956-2965 (2021).
A complete list of publications is available here.