Biography
Dr. Yi Fang
Dr. Yi Fang
Australian National University, Australia
Title: Equations of Life: Revealing Physical Laws of Protein Folding
Abstract: 
To resolve the protein folding problem, that is: predicting the native structure and describe the folding dynamics, we must work with the fundamental physical law that directly governs protein folding process. That law is the Thermodynamic Principle of Protein Folding, it is just the Second Law of Thermodynamics. In the protein folding case, the second law is that the Gibbs free energy achieves a minimum at the native structure.
Therefore, we have to figure out what is the Gibbs free energy. The question is, is there a Gibbs free energy function whose variables are all possible conformations of a given protein molecule? Or is it only a Gibbs free energy difference between the folded ensemble of protein molecules and its counterpart, the unfolded ensemble? The former is a microscopic view; the latter is a macroscopic view.

Completed Speech Abstract File
Biography: 
My last 18 years of research can be summarized as: A mathematician trying to solve a biological problem by revealing how fundamental physical laws govern protein folding. I first heard protein folding from Jiri Novotny. He told me that a folded globular protein has smaller volume, surface area, and better hydrophobic core than unfolded one. As a geometer used to calculus of variations, my instinct is that why not minimize volume, area, 5 and hydrophobic area (the smaller it is, the better the hydrophobic core) simultaneously and cohesively to get the native structure? A mathematical model was formulated during the conversation and was published [1]. In 2006 Junmei Jing and I participated CASP7, submitted our models [3], which were results of shrinking the hydrophobic area. Neglecting volume and area certainly will not give us good 3-dimensional models. But our models contain a lot of secondary structures and hydrogen bonds, even though we only calculated the gradient of the hydrophobic area function. This result confirms that I was on the right track. But we cannot just publish a mathematical model without computer simulation. Most of my papers were rejected without going to referees. Realzing that protein folding is a physics problem, I determined to study physics to prove my mathematical model has a firm physics foundation. I am used to teach myself. I was born in 1953, finished primary school in 1966, missed secondary education because all schools in China were closed down in 1966. After wasting 4 years, from 1970 to 1978, I worked as a farm labor. I tried to teach myself by reading textbooks. In 1997, I passed university admission examination of 1977, the first one in 12 years since 1966, entered Jilin University to learn mathematics. In 1985, I went to University of Massachusetts and got my PhD in 1990. Broad reading and mathematical skills enable me to learn biology, chemistry, thermodynamics, statistical and quantum mechanics, etc. After years of study, I created a new physical method to derive conformational Gibbs free energy function G(X; EN , U). As anticipated, it is a refined version of my original mathematical model. With more learning of physics, the microscopic thermodynamic hypothesis for protein folding follows suit.