FRACTAL STUDIES ON PROTEIN MOLECULAR CHAINS

A new method for the calculation of the fractal dimension (D) of a pro tein molecular chain and the D values of three kinds of protein are re ported. Thirty-nine proteins covering four structural classes of prote ins, selected from the protein data bank were computed. It was found t hat the mean value of fractal dimension of protein increased in order of the local D-L < middle mean D-M < global D-G for the short, middle and long range construction, respectively. The D value decreased in or der of alpha > alpha/beta > (alpha + beta) > beta for the structural c lasses of protein molecules. This suggests that the fractal dimension may be used to characterize the tertiary structure of a protein. As a structural quantity it reflects the morphology of a protein chain base d on the amino acid sequence.