Project Summary/Abstract
We request funds to purchase a Bruker Biospin Corp. Q-Band Elexsys E580 Pulse EPR
Spectrometer (Pulse EPR) to enable structural dynamics studies of proteins and their complexes and
the training of students and researchers. To maximize sensitivity, this instrument is equipped with a
300 W TWT Q-band pulse amplifier, ER5106QT-II resonator, SpinJet AWG, and Stinger cryogen-free
low-temperature system. The high sensitivity of the requested pulse EPR enables us to support projects
from user communities that are not feasible otherwise. In addition, combined with our current pulse
EPR instrument, having access to a second pulse EPR with enhanced sensitivity and capabilities is
essential, not only to manage our throughput, but also to serve as a regional pulse EPR facility for the
state of Missouri and nearby states. DEER spectroscopy as a powerful pulse EPR technique provides
an effective nanometer distance ruler to measure conformational changes in biomacromolecules under
relevant physiological conditions. With increasing technological advances in this ensemble-oriented
method, atomic resolution structural information can be directly linked to conformational sampling in
solution. Thus, mechanistic models for protein function can be obtained and DEER spectroscopy is
imperative to establish such models. The instrument will be housed in the Department of Biochemistry
and Molecular Biology at the Saint Louis University School of Medicine. The instrument will support
basic research of NIH-funded investigators at both Saint Louis University and Washington University in
St. Louis. We describe projects from 8 major and minor users with NIH grants that will benefit from the
requested instrumentation. The user projects span a range of membrane transporters, unconventional
protein secretion, blood clotting processes, biomolecular interactions in DNA repair and recombination,
immunothrombosis, regulation of protein translation, antimicrobial peptide transport, ligand-gated ion
channels, and membrane protein oligomerization. These projects focus on protein structure, functional
dynamics, and interactions, with majority involving low spin concentration samples. Thus, the high-
sensitivity Pulse EPR will be critical for these studies. Training for the Pulse EPR will be primarily
handled by members of the Dastvan research group who have more than a decade of experience using
the instrumentation, sample preparation, and data analysis. Users (graduate students, postdoctoral
fellows, and research associates) will be trained to independently use the Pulse EPR, and instrument
time will be determined using the existing scheduling system for departmental instrumentation. A local
advisory committee will provide oversight of the Pulse EPR and its operations. The high-sensitivity
Pulse EPR will be an integral component of the biophysical instrumentation portfolio at Saint Louis
University and will have a significant impact on the NIH-funded research in the region.