COMPUTER STUDY OF CONFORMATIONAL FLEXIBILITY OF 20 COMMON AMINO-ACIDS

Conformational potential energy hypersurfaces (PES) for the N-acetyl-N'-methylamides of all the 20 common amino acids have been analyzed by means of the molecular mechanics method in combination with the programs ROSE, DAISY, CICADA and PANIC. Global and fragmental flexibility f and phi, conformational softness f0 as well as flexibility of each conformation found have been computed for each residue. Rank correlation between the flexibility and Boltzmann probability, respectively, and the ability to form alpha-helix or beta-pleated sheet structure in a protein has been evaluated. It has been revealed that the ability to form alpha-helix or beta-pleated sheet correlates better with the conformational flexibility of single residues in the corresponding region than with the Boltzmann distribution of the corresponding single residue conformations in that region.