Coulomb energies of proteinprotein complexes with monopole-free charge distributions
From an analysis of Coulomb energy distributions of a large set of proteinprotein complexes we show that the positive tail in the energy distribution disappears when the monopolemonopole term, the only energy term independent of inter-subunit orientations, is removed. This indicates that unfavorable Coulomb energies associated with subunit orientations are excluded in proteinprotein complexes. The overall result remained unchanged when solvent effects were included. Our results have important bearing on the restriction of subunit orientations in proteinprotein complexes and complement a recent work [K. Brock, K. Talley, K. Coley, P. Kundrotas, E. Alexov, Optimization of electrostatic interactions in proteinprotein complexes, Biophys. J. 93 (2007) 33403352.] which showed that Coulomb energy of interaction in proteinprotein complexes is sequence-optimized.
electrostatics proteinprotein interactions monopole dipole