Multicanonical simulations of five tetrapeptide sequences in the central domain of HMW glutenin

The application of the multicanonical simulation method to small proteins a nd peptides seems to be feasible and should be undertaken. In this work, th e three-dimensional structures of five common tetrapeptide sequences (QPGQ, QSGQ, YPTS, SPQQ and QPGY, in one letter code) in the repetitive central d omain of HMW glutenin subunits are investigated by using the multicanonical simulation procedure. Ramachandran plots were prepared and analyzed to pre dict the relative occurrence probabilities of beta -turn and gamma -turn st ructures and helical states. Structural predictions of the five tetrapeptid e sequences indicated the presence of high level of p-turns and considerabl e level of gamma -turns. It was also possible to distinguish different type of turns and their occurrence probabilities.