Feb. 2024 – Eric Present his work ”Protein-Protein Interactions in the Phenylpropanoid and Flavonoid Pathways of Sorghum bicolor” at BPS 2024
June 2023- Jessica successfully defended her Ph.D. dissertation. Congrats Jessica!
March 2023- Faraz successfully defends his undergraduate thesis: ”Photophysical Rate Constants for Si and Ge Rhodamines in Water, 77K Glasses, and as a function of Oxygen Concentration”
He also presented his work at the annual WSU Symposium for Undergraduate Research and Creative Activity (pictured left). Faraz is set to graduate with his Bachelor of Science in Physics with minors in math and biology this spring. Congratulations Faraz!
February 2023- Jessica and Eric presented their thesis work at the annual Biophysical Society Meeting in San Diego
January 2023- ”Photophysical Rate Constants and Oxygen Dependence for Si and Ge Rhodamine Zwitterions” was published in the Journal of Physical Chemistry
Read it here! Abstract: The family of group XIV rhodamine zwitterions are fluorescence probes with carbon, silicon, germanium, or tin substituted in the 10-position of the xanthene ring. Because of their inherent near-infrared fluorescence, photostability and high quantum yields in aqueous solutions, the Si and Ge containing fluorophores in this class have become increasingly important for fluorescent labeling of proteins and biological molecules. This study fully characterizes photophysical rates derived from a model consisting of a singlet ground state, the lowest singlet excited state, and the lowest triplet excited state for two exemplar group XIV rhodamine zwitterions, one containing Si and the other Ge. Within a simple Jablonski diagram, all radiative and non-radiative rates, including intersystem crossing and triplet depopulation rates, were measured as a function of oxygen concentration. It was shown that the triplet depopulation rates are intrinsically fast in comparison with traditional xanthene containing fluorophores, probably due to the increased spin-obit coupling from the Si and Ge substitution in the xanthene ring. Dissolved oxygen increases both the intersystem crossing and triplet depopulation rates. Stern–Volmer analysis was conducted to estimate rates of quenching by oxygen. The experimental data was used to estimate the initial rates for reactive oxygen production by Si and Ge containing fluorophores in aqueous solutions containing different concentrations of dissolved O2. These estimates showed a significantly slower initial rate of reactive oxygen production in comparison with rhodamine 6G. This goes a long way to explaining their inherent photostability. Spectroscopic experiments were also conducted in 77 K viscous aqueous glasses where it was observed that the fluorescence spectra remained unchanged, and the quantum yields increased from 0.53 to 0.84 and from 0.52 to 0.89 for the Si and Ge containing fluorophores respectively; no phosphorescence was observed. All intersystem crossing and triplet depopulation rates were measured using fluorescence correlation spectroscopy (FCS) and analyzed using a new method that extrapolated the power dependence of the FCS curves to optical saturation. This method was verified using published data.
February 2022- Jessica presented her work ”Human Aquaporin-4 Orthogonal Array of Particles in Biomimetic Membranes: Aggregation, Protein Tracking and STED” at the Biophysical Society National Meeting in San Francisco
February 2022- ”Thermodynamic Driving Forces of Redox-Dependent CPR Insertion into Biomimetic Endoplasmic Reticulum Membranes” was published in Journal of Physical Chemistry!
Read it online here!
ABSTRACT: Cytochrome P450 reductase (CPR) is a NADPH-dependent membrane-bound oxidoreductase found in the endoplasmic reticulum (ER) and is the main redox partner for most cytochrome P450 enzymes. Presented are the measured thermodynamic driving forces responsible for how strongly CPR partitions into a biomimetic ER with the same lipid composition of a natural ER. Using temperature-dependent fluorescence correlation spectroscopy and fluorescence single-protein tracking, the standard state free energies, enthalpies, and entropies of the CPR insertion process were all measured. The results of this study demonstrate that the thermodynamic driving forces are dependent on the redox states of CPR. In particular, the partitioning of CPRox into a biomimetic ER is an exothermic process with a small positive change in entropy, while CPRred partitioning is endothermic with a large positive change in entropy. Both resulted in negative free energies and strong association to the biomimetic ER, but the KP of CPRox insertion is measurably smaller than that of CPRred. Using this new information and known results from literature sources, we also present a phenomenological model that accounts for membrane–protein interactions, protein orientation relative to the membrane, and protein conformation as a function of the redox state.
January 2022- Evan Taylor Successfully Defended his Ph.D. Dissertation! Congrats Evan!
November 2021 – Michael Martinez Successfully Defended his Ph.D. Dissertation! Congrats Michael!
Left to Right: Dr. Martinez and Dr. Brozik
October 2021 – The Brozik Lab Group Photo
Left to Right: Michael Martinez, Evan Taylor, Faraz Abounorinejad, Eric Jacobo, Ethan Villalovoz, Dr. Brozik, Aditi Dahiya, Jessica Carder, Daniel Rouhana
March 2021 – Jessica Carder Wins 1st Place at the GPSA Poster Session
Jessica took 1st place in the WSU Graduate and Professional Student Association Research Expo on March 30th 2021 for her thesis work “Stochastic Biophysics of Human Aquaporin-4: A Protein Tracking Study.” You can watch her poster presentation linked here
2018 – The Brozik Lab Group Photo
Back row (left to right): Dr. J. A. Brozik, Heather Heidenreich, Evan Taylor, Michael Martinez, Dr. Bryan Boarders
Front row (left to right): Jessica Carder, Boris Lam, Steven Mather, Payton Bredstrand, Dr. Alexandre Dixon, Sajad Alsadah