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Curriculum Vitae




  • Principles of Chemistry I & II

  • Science Foundations

  • Biochemistry I, II, & Lab

  • Physical Chemistry II & Lab

  • Advanced Laboratory I & II

  • Environmental Chemistry

  • Instrumental Analysis

  • Analytical Chemistry

  • Quantum Chemistry

  • Physical Biochemistry



Dr. John E. Hansen, Ph.D.

Associate Professor

Office:  2126 TLC , Lab:  2110 TLC




Ph.D. Physical Chemistry, University of Chicago, 1991

B.S. Chemistry, University of Wisconsin, 1980

B.S. Mathematics, University of Wisconsin, 1980


Research Interests:


I am an experimental physical chemist interested in studying the dynamics of chemical and biological systems using optical and laser spectroscopy.  A major focus in my group is to determine the folding pathway a polypeptide chain will follow to finally arrive at a unique three dimensional protein structure. 


Examining the process of protein folding raises a fascinating paradox.  It is known that a polypeptide will spontaneously fold to the correct, unique three-dimensional protein structure within a test tube outside a cell.  The average-sized protein consists of 270 amino acids.  Each amino acid can adopt around 10 different conformations, so the average-sized protein could assume up to 10270 different three-dimensional structures.  To give this number some meaning, realize that astronomers estimate the number of atoms in the universe to be 1087.  Also consider that the fastest chemical event is a molecular vibration, which occurs in one-tenth of a picosecond (10-13 s).  If a polypeptide chain were to sample each of the available conformations for a duration of only one-tenth of a picosecond, it would take longer than the history of the universe to arrive at the correct three-dimensional structure for the average-sized protein!  Yet, we know polypeptides can fold to the correct structure in a test tube in less than a second – sometimes a few milliseconds.


Although protein folding is an extremely interesting theoretical problem, its study will answer important medical questions. A number of diseases result from misfolded proteins: Alzheimer’s, bovine spongiform encephalopathy (“mad cow” disease), Jacob-Kreutzfeld disease (the human equivalent of mad cow disease), amyloidosis, cystic fibrosis, sickle cell anemia and osteogenesis imperfecta (brittle bone disease). Understanding the process of protein folding, and those forces that stabilize a protein structure will yield beneficial insights that will help society.