The number of hydrogen bonds during the simulations was calculated using the TAMD program [Math. Biol. Bioinform. (Russian). 2009, 4, 36-45]. The geometric criteria of hydrogen bond formation were as follows: the donor-acceptor distance is within 2.55 Α and the donor-hydrogen-acceptor angle is more than 140 degrees. We considered two variants of hydrogen bonds: the backbone hydrogen bonds (donor and acceptor belong to the protein backbone) and the side-chain hydrogen bonds (donor and acceptor belong to the protein side-chains).
The number of atom-atom contacts per residue in protein was calculated in the following way: two atoms were considered in contact with each other if their centers were at a distance of less than 6 Α. The atom-atom contacts between two adjacent residues as well as within one residue were not taken into account.