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Comet Calendar

Distributed Dynamics of Enzyme Active Sites: Insights from 2D IR Spectroscopy (Speaker: Dr. Sean D. Moran, Southern Illinois University; Host: Dr. Allison Stelling)

Friday, October 1, 2021 at 3:30pm to 4:30pm

Sciences Building, SCI 1.210

The Department of Chemistry and Biochemistry will be holding seminar series every Friday between 3:30pm-4.30pm starting on Sep 3rd (second week of the semester). The seminars will be presented either virtually via BbCollaborate or in person (Room SCI 1.210).

This seminar will take place on Friday Oct. 1st and  will be delivered in person (Speaker: Dr. Sean Moran, Southern Illinois University; Host: Dr. Allison Stelling). In light of the class de-densification guidelines, this seminar will also be live-streamed via MS Teams. The link can be provided upon request (please contact Dr. Gabriele Meloni at

Title: Distributed Dynamics of Enzyme Active Sites: Insights from 2D IR Spectroscopy

Abstract: The active sites of enzymes are specialized solvent environments that catalyze biochemical reactions by lowering free energies of activation. Much of this effect arises from the preorganization of polar residues, which reduces the penalty for solvent reorganization. Because solvation is a complex phenomenon, many researchers have proposed that femtosecond-picosecond timescale dynamics of enzymes may also play a role in catalysis However, no consensus has been reached regarding their characteristics or their importance. My research group uses ultrafast two-dimensional infrared (2D IR) spectroscopy and site-specific labeling to extract information regarding the fluctuations of the local environment about enzyme-bound substrate analogs, as well as the intramolecular vibrational dynamics of the analogs themselves. These observations reflect combinations of localized solvent effects including non-equilibrium solvation, friction, viscosity, and responses to perturbations. In my talk, I will discuss how 2D IR senses electrostatic and dynamical anisotropy in the active site of Pyrococcus horikoshii ene-reductase (PhENR), how nanometer-scale differences in fast (femtosecond – picosecond) timescale dynamics may impact its reactivity, and how explicit consideration of distributed solvent effects may help to unify competing hypotheses of enzyme function. I will also discuss current challenges, experimental and computational strategies to address them, and new opportunities provided by the PhENR model system. Finally, I will discuss how we are applying 2D IR spectroscopy to other systems to examine cofactor-dependent dynamics and the influences of crowding/viscosity on occluded active site dynamics.

Follow us on Comet Calendar for more information about our seminar series. Enjoy it!

Persons with disabilities may submit a request for accommodations to participate in this event at UT Dallas' ADA website. You may also call (972) 883-5331 for assistance or send an email to All requests should be received no later than 10 business days prior to the event.

Event Type

Lectures & Workshops

Target Audience

Graduate Students





Natural Sciences & Mathematics
Contact Information
Dr. Gabriele Meloni
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