Patent ID: 7158891

Claim:
A method for modeling the three dimensional structure of a molecule by determining the lowest value of conformational potential energy of a molecule by using an algorithm to define the lowest value of the conformational potential energy as the best conformation representing the three dimensional structure of the molecule, said algorithm comprising the steps of: a) representing the molecule in terms of coordinates defined by torsion angles of the atoms comprising the molecule; b) specifying the number of torsion angles, n, the range of each n torsion angle, and a step size at which the values of each torsion angle is sampled, there being a total of m steps for each torsion angle, θ r,s ,r=1 to n and s=1 to m as the input set of values for each torsion angle selected; c) selecting a set of all possible conformations of the molecule represented by a combinatorial arrangement of Mutually Orthogonal Latin Squares (MOLS) of order N, wherein said MOLS are constructed based upon the n selected torsion angles of the molecule to provide N 2 sub squares in each set of MOLS, wherein N is a prime number obtained by R/m, R being 360°, with each MOLS sub square corresponding to one possible conformation of the molecule; d) labeling the sub squares of the MOLS by indices (u,t), u and t being integer numbers, u=1 to N and t=1 to N, and the value of the rth torsion angle in a given sub square (u,t) being chosen from the input set of values θ r,s as θ u , t r = θ r , s in which the index u is given by u={(t−1)(r−1)+(s−1)} modulo(N); e) repeating the procedure of filling up the sub squares of the MOLS with the values chosen for r=1 to n, s=1 to m, and t=1 to N, with u being calculated each time by the formula given in step (d), until each sub square of the N 2 MOLS sub squares are filled with a set of n values, each value defining one conformation of the molecule, resulting in N 2 conformations; f) calculating the potential energy for each of N 2 conformations of the molecule in accordance with V u , t = V ⁡ ( θ u , t r ) , g) analyzing the set of N 2 values obtained to determine a best value for each torsion angle, by determining the average value of the potential energy for each torsion angle at all the N conformations, there being n×m average values, the set of average values being determined according to the formula: < V ⁢ > s r = ∑ t ⁢ V ⁡ ( θ u , t r ) ⁢ exp ⁡ ( - V ⁡ ( θ u , t r ) / κ ⁢ ⁢ T ) ∑ t ⁢ exp ⁡ ( - V ⁡ ( θ u , t r ) / κ ⁢ ⁢ T ) ; h) scanning the set of n×m average values of the potential energy obtained for each torsion angle, to determine the lowest average value of the potential energy to define a best conformation of the molecule; i) confirming the results obtained by choosing a different set of values for the torsion angle and repeating steps e) to i); and j) outputting the best conformation of the molecule to a user of said method.