Hoi Sung Chung, Ph.D.

Current Research

Single Protein Conformational Dynamics: Folding, Binding, and Aggregation of Disordered Proteins

We study conformational dynamics of proteins using single molecule Förster resonance energy transfer (FRET) spectroscopy. Especially, we focus on intrinsically disordered proteins (IDPs) that are closely related to various human diseases. The primary goal of our research is to understand the mechanisms of binding and aggregation processes of IDPs.

1. Understanding binding mechanism of IDPs. We try to understand the mechanistic details of binding: how molecular conformations evolve when two molecules approach to each other, make a contact, and form a bound complex. This information is contained in the moment of binding that can be probed only by single molecule spectroscopy.
2. Characterization of protein aggregation. Protein aggregates and oligomers are thought to be implicated in the development of various neurodegenerative diseases. However, oligomerization and aggregation have been extremely difficult to study due to the heterogeneity of the process. Single molecule spectroscopy can effectively characterize this complicated process by detecting individual molecular species without separation.

Postdoctoral Positions

Postdoctoral positions are available. To apply email a CV, bibliography, brief summary of research accomplishments, and the names of references.

Research in Plain Language

Proteins play critical roles in virtually every cellular process. To perform their biological functions, they must properly fold into a unique three-dimensional structure. However, it is predicted that a surprisingly large fraction (> 30 percent) of proteins stay unfolded or contain unstructured regions. These unstructured proteins are called intrinsically disordered proteins (IDPs). Interestingly, IDPs fold when performing their biological functions: binding to target proteins. The intrinsic disorder is found in many proteins performing central roles in cellular regulation such as gene transcription and signal transduction and therefore is frequently implicated in the development of various diseases such as cancers. In addition, disordered proteins are often prone to aggregation, which also causes various protein misfolding diseases such as Alzheimer’s disease and Parkinson’s disease.

We study protein binding and aggregation processes of IDPs by watching one molecule at a time using single molecule spectroscopy. Recent development of various single molecule techniques has allowed monitoring heterogeneous biological processes. Studying the heterogeneity is particularly important for understanding the binding and aggregation mechanisms because conformational transitions of proteins are intrinsically heterogeneous.