About

Steven Boxer is the Camille Dreyfus Professor of Chemistry at Stanford University. He earned his PhD from the University of Chicago in 1976, specializing in Physical and Physical-Organic Chemistry, and his BS with Honors in Chemistry from Tufts University in 1969. His laboratory investigates the structure and function of biological systems through a physical perspective, developing experimental methods and theories as needed. His research encompasses several interconnected themes, including the excited state dynamics in Green Fluorescent Protein (GFP) and split GFP, where his team demonstrated the existence of two protonation states of the GFP chromophore that interconvert via ultrafast excited state proton transfer. This work has led to the development of GFP variants with diverse colors and sensitivities. His group also explores the optogenetic applications of split GFPs, which can be photodissociated or associated with peptides using light. Additionally, Boxer studies electrostatics and dynamics in proteins, utilizing Stark spectroscopy and vibrational probes to measure electrostatic fields within proteins and their influence on enzymatic activity. His research extends to model membranes, where supported lipid bilayers serve as mimics for cell surfaces, enabling the study of membrane organization, fusion, and protein interactions. His work in energy and electron transfer in photosynthesis involves femtosecond spectroscopy and mutagenesis to understand electron transfer pathways in bacterial reaction centers, including the use of non-canonical amino acids to probe these pathways. Overall, his research aims to elucidate fundamental biological processes through a physical and chemical lens, advancing our understanding of protein function, membrane dynamics, and bioenergetics.

Research topics

• Stereochemistry
• Quantum mechanics
• Chemical physics
• Computational chemistry
• Organic chemistry
• Atomic physics
• Chemistry
• Physics

Selected publications

• BPS2026 – Who's really in charge? Dissecting directional electric fields in enzyme catalysis

  Biophysical Journal · 2026-02-01

  articleSenior author
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• Magnetic resonance control of spin-correlated radical pair dynamics in vivo

  Nature · 2026-03-18

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• BPS2026 – Interplay of electrostatics and conformational dynamics in dihydrofolate reductase catalysis

  Biophysical Journal · 2026-02-01

  articleSenior author
  PublisherDOI

• BPS2026 – Magnetic-resonance control of spin-correlated radical pair dynamics in a transgenic animal

  Biophysical Journal · 2026-02-01

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  PublisherDOI

• BPS2026 – Electrostatic insights into X-H···π interactions (X = C, N, O, S) through the vibrational Stark effect

  Biophysical Journal · 2026-02-01

  articleSenior author
  PublisherDOI

• BPS2025 - An investigation into the origins of vibrational freqeuncy tuning for the green fluorescent protein chromophore

  Biophysical Journal · 2025-02-01

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• BPS2025 - The vibrational stark effect in carboxylates: A sensitive probe of electric fields in proteins

  Biophysical Journal · 2025-02-01

  articleSenior author
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• Covalent Drug binding in Live Cells Monitored by Mid-IR Quantum Cascade Laser Spectroscopy: Photoactive Yellow Protein as a Model System

  bioRxiv (Cold Spring Harbor Laboratory) · 2025-08-19

  preprintOpen accessSenior authorCorresponding

  The detection of drug-target interactions in live cells enables analysis of therapeutic compounds in a native cellular environment. Recent advances in spectroscopy and molecular biology have facilitated the development of genetically encoded vibrational probes like nitriles that can sensitively report on molecular interactions. Nitriles are powerful tools for measuring electrostatic environments within condensed media like proteins, but such measurements in live cells have been hindered by low signal-to-noise ratios. In this study, we design a spectrometer based on a double-beam quantum cascade laser (QCL)-based transmission infrared (IR) source with balanced detection that can significantly enhance sensitivity to nitrile vibrational probes embedded in proteins within cells compared to a conventional FTIR spectrometer. Using this approach, we detect small-molecule binding in E. coli, with particular focus on the interaction between para-coumaric acid (pCA) and nitrile-incorporated photoactive yellow protein (PYP). This system effectively serves as a model for investigating covalent drug binding in a cellular environment. Notably, we observe large spectral shifts of up to 15 cm -1 for nitriles embedded in PYP between the unbound and drug-bound states directly within bacteria, in agreement with observations for purified proteins. Such large spectral shifts are ascribed to the changes in the hydrogen-bonding environment around the local environment of nitriles, accurately modeled through high-level molecular dynamics simulations using the AMOEBA force field. Our findings underscore the QCL spectrometer's ability to enhance sensitivity for monitoring drug-protein interactions, offering new opportunities for advanced methodologies in drug development and biochemical research.

  PublisherOA PDFDOI

• A Comprehensive Test of the AMOEBA Force Field Using Spectroscopy, Structures, and Simulations of Nitrile Protein Environments

  ChemRxiv · 2025-12-29

  articleOpen accessSenior author

  Local noncovalent interactions including hydrogen bonds (H-bonds) generate electric fields that are essential for biological assembly and function. We recently demonstrated that a nitrile’s (–C≡N) infrared (IR) transition dipole moment (TDM) and anomalous H-bond frequency blueshift can report on its environmental electric field and H-bond geometry and dynamics, respectively. Here, we expand on prior work with nitriles site-selectively incorporated into photoactive yellow protein by introducing mutations designed to alter local nitrile H-bonding and electrostatics. A comprehensive analysis combining IR data, high-resolution X-ray crystal structures, and extensive molecular dynamics simulations demonstrates that the multipolar, polarizable AMOEBA force field accurately models electrostatics and H-bond geometries in both fast and slow H-bond exchange regimes. This finding is reached by correlating experimentally and computationally derived –C≡N electric fields and H-bond blueshifts exhibiting different H-bond fluctuation timescales. This implies that AMOEBA correctly models thermodynamic and kinetic aspects of noncovalent interactions. The diverse, thoroughly characterized collection of –C≡N protein environments reported herein provide a benchmark for next-generation molecular dynamics force fields that incorporate higher level descriptions of molecular electrostatics.

  PublisherDOI

• Electrostatic atlas of non-covalent interactions built into metal–organic frameworks

  Nature Chemistry · 2025-08-27 · 8 citations

  articleOpen accessSenior author

  Non-covalent interactions are central to the organization of matter and molecular recognition processes, yet they are difficult to characterize. Here we devise a platform strategy to systematically build non-covalent interactions with selective chemical groups into precisely designed configurations by using metal–organic frameworks (MOFs) as the molecular scaffold. Using the vibrational Stark effect benchmarked against computer models, we find the electric field provides a unifying metric for quantifying diverse non-covalent interactions in MOFs and solvation environments. We synthesize and analyse spectroscopically a collection of non-covalent interactions using a nitrile probe within the MOF structure, and identify stabilizing fields as strong as −123 MV cm−1 produced additively by multiple hydrogen bonds, an unusual destabilizing field of +6 MV cm−1 between antiparallel dipoles, anomalous hydrogen-bond blueshifts as large as 34 cm−1 and unique solvation under nanoconfinement. This method for making and testing non-covalent interactions opens new avenues for exploring non-covalent interactions. Non-covalent interactions are very diverse, and they are generally difficult to investigate through experimental methods. Here tailored metal–organic frameworks serve as a platform for the systematic generation of a variety of non-covalent interactions, which can be studied through the electric fields produced by the charges and dipoles involved in the interactions.

  PublisherOA PDFDOI

Recent grants

• Organization and Dynamics in Photosynthetic Reaction Centers and Model Membrane Architectures

  NSF · $1.4M · 2014–2019

• Mechanism and Macromolecular Organization in Photosynthetic Reaction Centers

  NSF · $931k · 2004–2010

• Organization and Dynamics in Photosynthetic Reaction Centers and Model Membrane Architectures

  NSF · $1.2M · 2019–2024

• NIH Grant R01GM027738

  NIH · $5.7M · 2017

• Biophysical studies of macromolecules and molecular assemblies

  NIH · $6.5M · 2016–2027

Frequent coauthors

• Seth R. Marder

  86 shared

• Stefan Franzen

  North Carolina State University

  85 shared

• William H. Woodruff

  University of Illinois Urbana-Champaign

  60 shared

• Gerold U. Bublitz

  Stanford University

  58 shared

• S. James Remington

  University of Oregon

  41 shared

• Melissa Thomas

  40 shared

• G. I. Stegeman

  King Fahd University of Petroleum and Minerals

  36 shared

• Jun Li

  36 shared