Allosteric Drug Discovery using Quantum Cascade Laser based Anisotropic THz Microscope (QCL-ATM)

Allosteric Drug Discovery using Quantum Cascade Laserbased Anisotropic THz Microscope (QCL-ATM) Proposal in Response to NIH/NIGMS STTR PA-20-265 This STTR will result in a commercially viable instrument that will enable critical research in allosteric drugs and protein dynamics. To date allosteric inhibitors are largely found serendipitously. Anisotropic THz microspectroscopy (ATM) uniquely measures the long range structural vibrations which serve as a mechanism for allosteric control. ATM provides a tagless means to experimentally determine allosteric target sites. There are NO commercial methods that provide this information currently. ATM systems used to establish the technique are not accessible to a standard biochemical lab. In this STTR we will develop a compact system for turnkey operation by academic and industrial researchers. This will be achieved by a collaboration of optical engineers and biological physicists with unique expertise required. The system requires 1) high power tunable THz source; 2) THz optical system for micro spectroscopy with polarization control; 3) high sensitivity room temperature detection integrated into the microspectroscopy system; and 4) easy user interface. The LongWave Photonics group has innovated high power compact THz sources (quantum cascade lasers, QCL’s) and turn-key measurement systems based on these sources. The Markelz group at UB has innovated ATM. The system, QCL-ATM, will be a turnkey tabletop instrument. In phase I the QCL-ATM will be developed to directly probe vibrations within molecular standards (e.g. sucrose, fructose, and glucose and the protein crystal tetragonal lysozyme) using polarized THz radiation within the 1.6 – 4.3 THz range of our QCL source and measure the change in absorbance as the relative orientation of the crystal molecular samples and polarization axis is varied. Using this demonstration of an integrated QCL-ATM instrument, we will identify the optical and mechanical tolerances associated with the need to place both the sample and the detector entirely within the near-field region of a focused THz beam as preparation for Phase II which will include measurement of the effect of allosteric drugs on protein vibrations and the development of an automated polarization control module and automated multi-sample platen with repeatable high-precision sample alignment to the interrogating THz beam. The specific aims for Phase I are: Aim 1. Construct and Characterize throughput QCL-ATM Microscope in the Far-field. Aim 2. Characterize anisotropic absorbance with the QCL-ATM for molecular crystal standards. Aim 3. Integrate near field pyroelectric detection into the QCL-ATM prototype and establish equivalence to existing systems by measuring spectra of protein crystalAllosteric Drug Discovery using Quantum Cascade Laserbased Anisotropic THz Microscope (QCL-ATM) Proposal in Response to NIH/NIGMS STTR PA-20-265 We propose to develop a benchtop spectroscopic system for rapid characterization of protein structural dynamics based on terahertz polarimetric spectroscopy (anisotropic terahertz microscopy, or ATM). The unique capability of this system to reveal previously unattainable information builds on the proposer’s previous work by incorporating the recently developed high-power tunable terahertz source: the terahertz quantum cascade laser (QCL). This lower complexity system will enable more researchers to perform studies for the development of allosteric drugs, as well as increase the understanding of the impact of remote small molecule binding and mutation.