Prediction of Conformation in Peptides

A simple and popular method for the prediction of conformation is the application of empirical conformational parameters. From the study of numerous protein structures determined by x-ray crystallography it became obvious that certain amino acids are frequent constituents of helical portions while others are more likely to occur in j -sheets and still others are often found in reverse turns. Statistical treatment of such frequencies (Chou and Fasman 1978) produced sets of conformational parameters (Table 5) which were applied for the prediction of conformation in proteins with considerable success. A cluster of four helical residues (P 1.00) in a six residue stretch of a chain is predictive for a helical region that can be extended in both directions until a 

is the statistical probability for a residue to be in an a-helical region P is the statistical probability for a residue to be in a -sheet region 

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