The conformational and physico-chemical features (properties mean values) of the site

For a nucleotide sequence S={s_{1}...s_{i}...s_{L}}, of the length L, containing dinucleotide s_{i}s_{i+1} at the i-th position the mean value X_{k} of the k-th __conformational or physico-chemical property__ averaged over the region [a; b] (1£ a£ b£ L) of the sequence S is calculated as follows:

Applying equation (1) to the site sequence set {S} at fixed k, a, and b yields the distribution X_{k,a,b}{S} for the site sequences. Similarly, the distribution, X_{k,a,b}{R} is generated for random sequences {R} with the same nucleotide frequencies as in the real sequences. The difference between these distributions X_{k,a,b}{S} and X_{k,a,b}{R} is tested for significance by calculating of the __utility value__ U(X_{k,a,b}), which is the integral characteristic of the discriminating ability of X_{k,a,b}.