Research

Protective Electron Transfer Pathways in Oxidative Enzymes

Enzymes that activate oxygen, like cytochromes P450 and multicopper oxidases, perform some of biology’s most chemically challenging reactions. However, these high-energy transformations risk generating reactive intermediates that can damage the enzyme itself. My research investigates how these enzymes protect themselves during catalysis by leveraging internal electron (hole) transfer pathways composed of tryptophan and tyrosine residues. These aromatic chains can reroute oxidizing equivalents away from the active site, extending the enzyme’s functional lifetime.

I focus on the self-sufficient cytochrome P450BM3, where previous work in our group has demonstrated that disrupting key residues (like W96) significantly decreases enzyme stability, especially under low NADPH conditions. Using total turnover number (TTN) as a metric for enzyme survival, I am evaluating the protective role of these redox-active residues. I am complementing these studies with site-directed mutagenesis, kinetics modeling, and stopped-flow spectroscopy using ruthenium-based redox probes to directly track hole migration to the enzyme surface.

Building on this work, I’ll extend these concepts to other P450 enzymes that rely on external redox partners, as well as to multicopper oxidases like the small laccase from Streptomyces coelicolor. These efforts aim to uncover universal strategies that oxidative enzymes use to avoid self-destruction—a question with implications for bioinorganic chemistry, enzyme design, and cellular redox balance.

Understanding and inhibiting Nsp1, a nonstructural protein in SARS-CoV-2

The SARS-CoV-2 virus, responsible for the ongoing global pandemic, has infected over 774 million people and caused more than 7.03 million deaths worldwide as of March 2024. Upon entering host cells, the virus’s positive-sense single-stranded RNA genome is translated into 29 viral proteins. Among the earliest expressed is a polyprotein that is cleaved into 16 nonstructural proteins (Nsps), including Nsp1, a key virulence factor that suppresses host immune responses by selectively inhibiting host protein translation. Cryo-EM studies have shown that residues 148–180 of Nsp1 adopt a helix-turn-helix motif upon binding to the 40S ribosome, effectively plugging the mRNA entry tunnel. At 1 μM, Nsp1 can reduce in vitro host translation efficiency by over 90%. The intrinsically disordered nature of its C-terminal (CT) domain presents challenges for structure-based drug design.

My research focuses on characterizing the structural dynamics and metal-binding properties of this disordered CT region. I have shown that aquo copper(II) binds selectively to histidine 165 in a synthetic 33-residue C-terminal peptide of Nsp1. Building on this, I am now examining how metal binding, including both copper(II) and cobalt(III) complexes, affects the structure and function of full-length Nsp1 and its variants. These studies aim to provide molecular-level insights into how transition metals may modulate Nsp1’s interaction with the host translation machinery.

Throughout this project, I have developed expertise in protein expression and purification, SDS-PAGE, mass spectrometry, and X-ray crystallography. I also use a suite of biophysical techniques, including tryptophan fluorescence (W161), time-resolved Förster resonance energy transfer (TR-FRET), electron paramagnetic resonance (EPR) spectroscopy, and circular dichroism. Complementing these tools, I perform in vitro translation assays to probe the functional impact of metal coordination on ribosome inhibition.

Research Experiences

Merck Future Talent Program Intern in Discovery Biologics

I have investigated the role of glycosylation in the function and folding of a pharmaceutically relevant protein by designing various deglycosylated and glycosylated mutants. My work involved the expression, purification, and characterization of these protein constructs. I tested the constructs using ELISA assays and a range of in vitro functional assays to assess their properties and behavior.

Summer 2023, Merck Research Laboratories, South San Fransisco

For students interested in applying to this internship visit the following:

Merck Future Talent Program

Undergraduate Researcher with Dr. Valentine Vullev

I synthesized biomimetic molecular electrets incorporating non-native amino acid residues and characterized various charge transfer organic compounds using advanced techniques such as UV-Vis spectroscopy, fluorescence spectroscopy, and transient absorption spectroscopy. See Publications for work done on these projects.

June 2017-June 2020, University of California Riverside, Riverside

Funding for my research from 2018-2020 was provided by the NIH through MARC U Star Program. For students at UCR interested in applying please visit the following:

MARC U Star Program at UCR

WAVE Fellow with Dr. Harry Gray

I synthesized and purified meso-substituted corroles and characterized their photophysical properties using UV-Vis spectroscopy. Additionally, I analyzed these corroles for their potential applications in cancer theranostics.

June 2019- August 2019, California Institute of Technology, Pasadena

For students interested in applying to this program visit:

Caltech WAVE Fellows

DAAD RISE Fellow with Dr. Jens Pietsch

I synthesized and purified cathepsin B inhibitors for cancer treatment and tumor radiolabeling. These inhibitors were characterized and tested using relevant assays. See Publications for work done on these projects.

June 2018-August 2018, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany

For students interested in applying to this program visit:

DAAD RISE

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