About

Rachel Martin is a Professor at the University of California, Irvine, within the Department of Chemistry. Her research interests encompass Analytical Chemistry, Chemical Biology, Physical Chemistry, and Chemical Physics. She is involved in advancing knowledge in these areas through her academic and research activities at UC Irvine, contributing to the department's focus on interdisciplinary scientific inquiry and education.

Research topics

• Biology
• Computer Science
• Computational biology
• Genetics
• Chemistry
• Biochemistry
• Medicine
• Organic chemistry
• Virology
• Materials science
• Nanotechnology
• Biophysics

Selected publications

• BPS2026 – Probing the biophysical properties of Ciona intestinalis βγ-crystallin

  Biophysical Journal · 2026-02-01

  articleSenior author
  PublisherDOI

• Jasmonate signaling and prey nutrient availability trigger distinct biochemical responses in the <i>Drosera capensis</i> feeding cycle

  PLANT PHYSIOLOGY · 2026-01-17

  articleOpen accessSenior author

  The Cape sundew (Drosera capensis) is a carnivorous plant native to South Africa. Central to its prey capture and digestive processes is a complex array of biochemical processes that trigger the production of enzymes and small molecules. These processes are in part activated by the release of jasmonic acid, a plant defense hormone repurposed as a prey detection signal. Here, we use RNASeq and untargeted metabolomics to study the response of D. capensis to feeding stimuli. We confirm the expression of genes encoding digestive proteins predicted in prior genomic work and show up- and down-regulation for a number of enzyme classes in response to jasmonic acid. Metabolomics experiments indicate that many small molecules produced during feeding depend on specific nutrient inputs from prey (and not merely a jasmonic acid stimulus). These results shed light on the molecular basis of plant carnivory and the recruitment of existing biochemical pathways to perform specialized functions in Caryophyllales carnivorous plants.

  PublisherOA PDFDOI

• Mimicking oxidative damage in γS-crystallin with site-specific incorporation of 5-hydroxytryptophan

  Biophysical Reports · 2026-01-18

  articleOpen accessSenior author

  The human eye lens plays an essential role in vision by focusing light onto the retina. This transparent tissue consists of densely packed crystallin proteins that exhibit remarkable solubility despite minimal protein turnover. Post-translational modifications that accumulate over a lifetime can reduce crystallin solubility, resulting in the precipitation or phase separation of protein aggregates. Oxidation is a common type of modification that can cause such opacification of the lens, particularly in age-related cataract. Here, we study the oxidation of W163 in γS-crystallin, a structural lens protein that is particularly vulnerable to oxidative stress. We were motivated by previous findings reporting the oxidation of this residue in diseased and UV- and γ-irradiated samples. Using genetic code expansion (GCE), we incorporated an oxidation mimic, 5-hydroxytryptophan (5HTP), at position 163 of γS-crystallin (γS-W163(5HTP)). This subtle change in the structural and electronic properties of its side chain is hypothesized to destabilize the hydrophobic core of the C-terminal domain. γS-W163(5HTP) was characterized and compared to the wild-type (γS-WT). Although the overall fold and stability of the two proteins were comparable, the aggregation of γS-W163(5HTP) was triggered at notably lower temperatures compared to γS-WT. Subsequent investigation of this observation using both simulations and experiments suggests a potential mechanism for polymerization as well as oxidation-induced conformational changes that may cause susceptibility to thermal aggregation. Our findings highlight the utility of GCE platforms for systematically evaluating the impact of post-translational modifications on disease-related proteins.

  PublisherDOI

• BPS2026 – An eye lens protein forms a transparent hydrogel via transient intermolecular interactions

  Biophysical Journal · 2026-02-01

  articleSenior author
  PublisherDOI

• BPS2026 – Site-specific incorporation of 5-hydroxytryptophan mimics oxidative damage in a human eye lens protein

  Biophysical Journal · 2026-02-01

  articleSenior author
  PublisherDOI

• Differential expression and untargeted LC-MS metabolomics reveal jasmonate-induced assimilation of prey nutrients and upregulation of enzymes and small molecules

  OSF Preprints (OSF Preprints) · 2026-02-02

  other
  Publisher

• BPS2026 – Deamidation subtly changes biophysical and structural properties of an Antarctic toothfish protein

  Biophysical Journal · 2026-02-01

  articleSenior author
  PublisherDOI

• An Antarctic toothfish eye lens protein resists thermal stress even when extensively deamidated

  Biophysical Reports · 2025-11-05 · 1 citations

  articleOpen accessSenior author

  Crystallins are highly stable, soluble proteins that refract light and maintain transparency in the vertebrate eye lens. They are not replaced after early development, making them an excellent system for studying protein stability and solubility in crowded environments. To better understand the effects of deamidation on these ubiquitous vertebrate crystallins, we investigated a particularly extreme example, a lens protein from the long-lived Antarctic toothfish (Dissostichus mawsoni), γS1 crystallin (DmγS1). This protein remains soluble in the crowded fish lens, maintaining its transparency even at -2°C and at concentrations more than twofold that of humans (nearly 1000 mg/mL) and over a comparable timescale. As the organism ages, crystallins accumulate oxidative damage such as deamidation of Asn and Gln side chains, leading to aggregation and cataract. Previous studies of human γS crystallin (HγS) have shown that extensive deamidation reduces stability and increases aggregation propensity. Here, we present the biophysical characterization of wild-type DmγS1 and variants with three, five, and seven deamidation sites. In sharp contrast to results for human γS-crystallin, increasing the number of deamidations does not significantly change the thermal stability of DmγS1. These proteins are startlingly resistant to thermal denaturation; despite their psychrophilic origin, they have midpoint unfolding temperatures between 56°C and 63°C. Extensive deamidation does make the protein more vulnerable to chemical denaturation as well as aggregation below the unfolding temperature; however, all the variants resist aggregation well above the fish's physiological temperature. These proteins present a useful model system for aggregation resistance in extreme environments; most studies of protein solubility focus on unusually aggregation-prone proteins, but understanding the underlying biophysics also requires studying extremely soluble proteins.

  PublisherDOI

• Jasmonate-induced prey response in the carnivorous plant <i>Drosera capensis</i>

  bioRxiv (Cold Spring Harbor Laboratory) · 2025-07-20 · 1 citations

  preprintOpen accessSenior authorCorresponding

  Drosera capensis is a carnivorous plant native to South Africa. Central to its prey capture and digestive processes is a complex array of biochemical processes triggering the production of both enzymes and small molecules. These processes are in part activated by the release of jasmonic acid, a plant defense hormone repurposed as a prey detection signal. Here, we use RNASeq and untargeted LC-MS metabolomics to study the response of D. capensis to a feeding stimulus. We confirm the expression of digestive proteins predicted in prior genomic work and show up- and downregulation for a number of enzyme classes in response to jasmonic acid. Metabolomics experiments indicate that many small molecules produced during feeding depend on specific nutrient inputs from prey (and not merely a jasmonic acid stimulus). These results shed light on the molecular basis of plant carnivory and the recruitment of existing biochemical pathways to perform specialized functions.

  PublisherOA PDFDOI

• Design and Analysis of Untargeted Metabolomics Experiments

  Current Protocols · 2025-10-01 · 1 citations

  articleOpen accessSenior authorCorresponding

  Untargeted metabolomics is a powerful approach for identifying small molecules from highly complex mixtures, such as biological tissues or environmental samples. This technology enables the relatively fast and inexpensive identification of metabolites in situations where many or most of the chemical species are unknown before the experiment begins. This situation often arises in biomedical and environmental research, as well as in the case described here, the discovery of metabolites from plants. The objective of this paper is to provide practical and technical knowledge about untargeted metabolomics using mass spectrometry as the detection method. Specifically, we focus on liquid chromatography tandem mass spectrometry (LC-MS/MS). We provide a consolidated protocol for new users, serving as a starting point for experimental design, data collection, and data analysis. We explain the terminology and technical details in the context of real experiments and samples. In addition to general background information, step-by-step protocols are provided for sample preparation, liquid chromatography-tandem mass spectrometry data collection, and data analysis, utilizing readily available and widely used software. The chosen example data set is based on plant metabolites with varying chemical properties; however, the approach is applicable to essentially any complex biological sample. © 2025 The Author(s). Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Sample preparation for LC-MS/MS Support Protocol 1: Preparing a 'master mix' sample for assessment of liquid chromatography and sensitivity Basic Protocol 2: LC-MS/MS data collection Basic Protocol 3: Data analysis using the software MSConvert, MZMine, and SIRIUS Support Protocol 2: Using the MZMine batch file.

  PublisherOA PDFDOI

Recent grants

• Switched angle spinning NMR probes and stabilized membrane mimetics for oriented biomolecules

  NSF · $425k · 2013–2018

• CAREER: Switched-angle Spinning NMR for Investigation of Membrane Proteins

  NSF · $635k · 2009–2015

• Solid-state NMR methods for investigating native and aggregated eye lens proteins

  NIH · $2.8M · 2011–2025

• NIH Grant S10OD021594

  NIH · $139k · 2017

• Experimental and Modeling Study of the Optical Properties and Phase Behavior of Heat and Cold Tolerant Eye Lens Crystallins

  NSF · $525k · 2020–2025

Frequent coauthors

• Alexander Pines

  University of California, Berkeley

  47 shared

• Dimitris Sakellariou

  40 shared

• Carter T. Butts

  University of California, Irvine

  39 shared

• Carlos A. Meriles

  City College of New York

  29 shared

• Daniel Topgaard

  Lund University

  29 shared

• Brenna Norton‐Baker

  National Renewable Energy Laboratory

  27 shared

• Kurt W. Zilm

  Yale University

  20 shared

• Eric K. Paulson

  Yale University

  19 shared

Education

• Ph.D., Chemistry

  Yale University

  2002

• B.S., Chemistry

  Arizona State University

  1997