Proteins蛋白质的折叠问题.ppt

The Protein Folding Problem Yi Fang Proteins Proteins are the most important performers of life activities. They are natures robots. They participate in every life phenomenon: regulate physiological processes; catalyze chemical reactions; form supporting structures; transfer signals so that we can feel, hear, and see; form the immune system to deal with intruders; absorb energy from light; help replicate DNA; etc. Amino Acids Proteins are polymers, building from standard blocks called amino acids. There are 20 kinds of amino acids. Structures of Proteins Proteins can have infinite different structures, for example, by changing the ?I and ?I Native Structures of Proteins Although a protein can have infinite structures, only one shape, called the native structure of the protein, can perform the biological function of the protein. Wrong shapes of proteins, are causes of many diseases. Protein Folding An amino acids chain is a long and thin string. This string in space can form infinite different shapes. Only one shape, called the native structure of the protein, can perform the biological function of the protein. Protein Folding Physically, an amino acid chain is a very long and very thin string. In cell, a new amino acid chain, especially small ones (100 to 400 residues) will automatically fold to its native structure. This process is called protein folding. Protein Folding Problem Folding Code: what is the fundamental law of folding Structure prediction Folding process Dominate Force What is the dominate force in protein folding? Hydrogen bonding? Hydrophobic effect? Thermodynamical Principle The native structural of a protein is determined by its amino acid sequence Among all possible structures (conformations), the native structure has the least Gibbs free energy Structure Prediction From local to global Taking a global view Primary structure, the amino acid sequence, depends on the sequencing of DNA sequence Structure Prediction First principle Lac