Decomposition of\nForces in Protein: Methodology and\nGeneral Properties

In contrast to the central role played by the structure\nof biomolecules,\nthe complementary force-based view has received little attention in\npast studies. Here, we proposed a simple method for the force decomposition\nof multibody interactions and provided some techniques to analyze\nand visualize the general behavior of forces in proteins. It was shown\nthat atomic forces fluctuate at a magnitude of about 3000 pN, which\nis huge in the context of cell biology. Remarkably, the average scalar\nproduct between atomic force and displacement universally approximates\n−3<i>k</i><sub><i>B</i></sub><i>T</i>. This is smaller by an order of magnitude than the simple product\nof their fluctuation magnitudes due to the unexpectedly weak correlation\nbetween the directions of force and displacement. The pairwise forces\nare highly anisotropic, with elongated fluctuation ellipsoids. Residue–residue\nforces can be attractive or repulsive (despite being more likely to\nbe attractive), forming some kind of tensegrity structure stabilized\nby a complicated network of forces. Being able to understand and predict\nthe interaction network provides a basis for rational drug design\nand uncovering molecular recognition mechanisms.