Chemical biophysics of proteins in vitro and in vivo.

My main interest is the biophysics of protein misfolding in vivo and mechanisms of misfolding-associated diseases, discovery and pharmacological targeting of physiologically relevant non-native protein conformations, and protein engineering in currently inaccessible environments. To enable these lines of research, I develop new experimental methods at the interface of molecular biophysics and chemical biology and closely collaborate with computational biophysicists for computational-experimental integration..

Recent Research Outputs

We introduced a new technology in protein science: high-throughput disulfide scanning of protein conformations to map conformational landscapes to phenotypic landscapes in vivo. Achieving this required solving a partial case of the grand challenge of single-molecule protein deep sequencing: precisely locating the sequence positions of both Cys simultaneously in each double-Cys variant polypeptide.

We elucidated a biochemical mechanism of protein aggregation in the eye lens, which leads to cataract: a redox-driven “inverse-prion” aggregation phenotype, wherein wild-type human γD-crystallin dramatically promotes aggregation of its oxidation-mimicking W42Q variant. We showed that this reaction involves transfer of disulfide bonds from the C-terminal domain of the WT to the N-terminal domain of the mutant, locking the latter in an aggregation-prone conformation. This work has helped change our understanding of lens crystallin biochemistry by realizing that proteins formerly considered inert in fact have oxidoreductase activity and likely serve as a protein-based redox buffer in aging lens.

We opened the way to a potential first non-surgical treatment for age-onset cataracts. It reports that a highly abundant metabolite in the human eye lens, myo-inositol, has the previously unrecognized function of suppressing cataract-associated lens crystallin aggregation. Notably, many prior efforts to develop an anti-cataract therapeutic fell victim to the steep challenge of drug delivery to lens tissue; native myo-inositol transporters in the lens give this compound or its derivatives a natural advantage in this regard. We elucidated important aspects of the interaction between lens crystallins and transition metal ions, leading to pronounced aggregation but also formation of extraordinarily long-lived free radicals in human lens γD-crystallin, which has implications for protein-based radical chemistry during the process of lens aging and cataract development.