Research
Post-translational modifications (PTMs) are used by cells to modulate the function of proteins and respond to external stimuli. Deviations from homeostasis can signal a changing environment, aging, and disease. Thus, where and how frequently a protein is modified can be used as a diagnostic tool and—if intervention is necessary—identify potential druggable targets. Mass spectrometry is the primary method for the high-throughput identification of modified sites but there are still significant areas in need of improvement.
My research program strives to improve mass spectrometric-based detection and analysis of biomolecules. In particular, we pair mass spectrometry with chemical derivatization, photon irradiation, ion mobility, and radical chemistry to elucidate the three-dimensional structure of proteins, better characterize the acidic and hydrophobic proteome, and detect and localize PTMs. Centered at the interface of chemistry and biology, my research program provides students with the opportunity to tackle both biochemically-focused projects and biophysical questions at the core of the techniques themselves. Currently, my group is recruiting students for three projects:
1) IRMPD with a CO Laser: Mass spectrometric analysis of biomolecules relies on the dissociation of the analyte. Typically, collisions with gas molecules are used to initiate this dissociation (CID). There are several drawbacks, however, and irradiation with photons offers a promising alternative. This project aims to outfit the first mass spectrometer with a carbon monoxide laser, characterize the behavior of irradiated biomolecules, and apply infrared multiphoton dissociation (IRMPD) to instruments and at pressure regimes traditionally precluded from this technique.
2) Mass Spectrometric Analysis of Protein Conformation: The "shape" of a protein significantly influences its function and stability in solution. MS-based analysis of conformation is achieved by encoding the three-dimensional structure of the protein into its mass through reactions with small molecule probes. This MS technique enables the rapid analysis of low abundant analytes both in vitro and in vivo. Our lab utilizes this technique to investigate perturbations initiated by post-translational modification. Additionally, we will utilize a series of probes that enable temporal and spatial control of the reaction.
3) Negative-ion FRIPS Proteomics: Mass spectrometry is predominately applied in positive-ion mode and many dissociation techniques have been developed with this in mind. When applied in negative-ion mode these traditional techniques are either inefficient or not amendable to analysis via traditional bioinformatic techniques. Free-radical initiated peptide sequencing (FRIPS) offers significant advantages compared to other tandem mass spectrometry techniques and we aim to further develop the technique and apply it to complex mixtures of anions.
