Molecular Mechanics of Fundamental Biological Processes

Fundamental biological processes require the concurrent occupation of DNA by numerous motor proteins and complexes. Thus, collisions, congestion, and roadblocks are inescapable on these busy ‘molecular highways’. The consequences of these traffic problems are diverse, requiring complex molecular mechanisms to resolve threats to genome stability and ensure cellular viability. Additionally, the molecular highways are continually and dynamically restructured during these processes, altering highway topology and traffic flow.  

My laboratory focuses on the motion, dynamics and mechanics of DNA roadblocks, how DNA motor proteins collide and navigate through roadblocks, and DNA topology during transcription and replication. These highly complex problems require the development of real‐time techniques to decipher the actions of multiple players, while also simultaneously allowing the ability to mechanically control, alter, and measure DNA topology.  To work with biological motors and DNA at the single molecule level, we develop and utilize state-of-the-art (and often one-of-a-kind) instruments spanning optical trapping, magnetic tweezers, and nanophotonics.  These allow us to directly measure molecular extensions, forces, and torques on the scales of nanometers, piconewtons, and piconewton×nanometers.  We also combine our novel measurements with statistical mechanical models to better elucidate the mechanisms of these molecular machines.

Our precision measurements and models have enabled novel insights into the complex coordination of cellular machineries and the fundamental role of DNA mechanics and topology – including measurements of RNA polymerase torque generation capacity, mechanistic insights into lesion bypass during replication and subsequent re-initiation, and the intricate coordination mechanisms between RNA polymerase and the replisome or motor proteins.

• Member of the National Academy of Sciences, 2023
• Fellow, American Physical Society, elected 2009
• Provost's Award for Distinguished Scholarship, 2008
• Keck Foundation Distinguished Young Scholar in Medical Research Award, 2000-2007
• Beckman Young Investigator Award, 1999-2002
• Alfred P. Sloan Research Fellow, 1999-2001
• Dale F. and Betty Ann Frey Scholar of the Damon Runyon-Walter Winchell Foundation, 1999
• Damon Runyon Scholar Award, 1999-2000
• Damon Runyon-Walter Winchell Foundation Postdoctoral Fellowship, 1995-1997
• National Cancer Institute Fellowship, 1994
• University of Michigan Biophysics Fellowship, 1988-1989
• Outstanding Student Award, Nanjing University, 1985

• Professor, Physics, Cornell University, 2009-present
• Howard Hughes Medical Institute Investigator, 2008-present
• Associate Professor, Physics, Cornell University, 2004-2009
• Assistant Professor, Physics, Cornell University, 1998-2004
• Postdoctoral Fellow, Biophysics, Princeton University, 1994-1997
• Ph.D. in Biophysics, University of Michigan at Ann Arbor, 1993
• M.S. in Physics, University of Southern Mississippi, 1988
• Ph.D. student, Institute of Physics, Chinese Academy of Sciences, 1985-1986
• B.S. in Nuclear Physics, Nanjing University, 1985