Statement of Purpose

My early interest in biophysics can be traced back to my sophomore year at National Dong Hwa University. There I studied triplex DNA under the supervision of Dr. Chia-Ching Chang and Dr. Lou-Sing Kan of Academia Sinica. I wrote my own grant proposal, and received a research fellowship from the Republic of China National Science Council (NSC). This became my senior undergraduate thesis project: an independent investigation of pyrimidine motif triplex formation that earned an NSC Research Creativity Award. The conference papers that I wrote won financial support for my attendance at the 4th East Asian Biophysical Symposium in Taipei and the 48th Annual Meeting of the Biophysical Society in Baltimore.

During the past four years I have been very fortunate in having Dr. Shih-Hsiung Wu as my mentor for both my master’s thesis at National Taiwan University and my current research at Academia Sinica. Dr. Wu has given me a great deal of latitude in choosing topics, designing experiments, and writing research articles—that is, I have held full responsibility for all aspects of the publication process. He has consistently encouraged me with such advice as, “At most I can show you the road signs, but please remember that we are all finding our own way.” He has made the experience more than simply learning how to do technical research; I learned a lot about myself and about working with others to achieve a goal.

The focus of my research in Dr. Wu’s lab is a mitochondrial protein called Lon protease, a member of the AAA+ class of multifunctional proteins. In brief, I conducted a study of the physicochemical properties of hLon binding to G-quartet-forming oligonucleotides (GFOs). A combination of thermodynamic and spectroscopic data revealed that hLon is not only favorable to sequences that form G-quadruplexes (as compared to double helical and single stranded DNA), but also differentiates among GFOs through different levels of thermal fluctuation reduction. This is a very interesting finding in two contexts. In biological terms, our results provide direct evidence that hLon recognizes a sequence of mtDNA regulatory region coupled with structural tightening. In biophysical terms, the same results indicate that a new variable—DNA local structures—must be introduced to current theories of how DNA-binding proteins search for target sequences. For more detail, I invite you to read my report at http://nar.oxfordjournals.org/cgi/content/abstract/gkm1140v1?ck=nck.

In Dr. Wu’s lab I have continued working on several ideas emerging from my graduate research—for example, protein dynamics involved in the mitochondrial nucleoids and G-quartet formation on mtDNA (please see the research summary in the my CV at http://niwhu.blogspot.com/2008/10/rsum.html and my research statement at http://niwhu.blogspot.com/2008/10/research-statement.html). I am particularly interested in finding out whether G-quartet structures of mtDNA interact with potential G-quartet-binding proteins that reside in mitochondria (e.g., Lon, mtTop1) or translocate to mitochondria (e.g., TERT). I have spent time developing several possible methods for investigating these questions, including proteomics and fluorescence spectroscopy. Still, I recognize a need for further training and practice using such techniques as single-molecule fluorescence and cryo-electron microscopy, which allow for the detection of biomolecular energetics and dynamics in a scale-free manner. This year I wrote a proposal describing my Ph.D. research intentions and received a Republic of China Government Fellowship that will support my study in the US to develop these skills (http://niwhu.blogspot.com/2008/10/proposal-summary.html).