Molecular modeling of two hexapeptide repeat motifs of HMW glutenin subunits

The three-dimensional structures of two hexapeptide repeat motifs (PGQGQQ a nd SGQGQQ, in one letter code) in the repetitive central domain of HMW glut enin subunits are investigated by using the multicanonical simulation proce dure. Ramachandran plots were prepared and analyzed to predict the relative occurrence probabilities of beta -turn and gamma -turn structures and heli cal state. Structural predictions of PGQGQQ repeat motif indicated the pres ence of high level of beta -turns and considerable level of gamma -turns. S imulations of the repeat motifs in the repetitive central domain of HMW glu tenin subunits indicated that these structures take important part in the t hree-dimensional structures of repeat motifs.