DEVELOPMENT OF A NEW DENSITY-FUNCTIONAL PROGRAM FOR ALL-ELECTRON CALCULATION OF PROTEINS

In this article, we propose a new molecular orbital program for all-el ectron calculation of proteins which is based on density functional th eory. To carry it out in a fully analytical way, we adopted the (pure- ) analytical X alpha method and modified it for saving a lot of memori es for large-scale calculations. The recent software technology sophis ticated in information science is inevitably applied to achieve calcul ations of large molecular systems. The program is coded by the object- oriented language C++, its output is shown graphically, and the most o f the procedures in this program are controlled through an efficient g raphical user interface developed by ourselves. Such technology suppor ts the safe construction of the huge software, the tidy representation of enormous data, and the ready control of complex calculations. Test calculations with various sizes of glycine polypeptides indicate that the computation time is proportional to the 1.7 powers of the number of residues. This result suggests that the all-electron calculations o f proteins consisting of over 1000 atoms could be performed with distr ibuted and/or massively parallel computers. (C) 1997 John Wiley & Sons , Inc.