title: On the electrostatic properties of homodimeric proteins.
abstract: A large fraction of proteins function as homodimers, but it is not always clear why the dimerization is important for functionality since frequently each monomer possesses a distinctive active site. Recent work (PLoS Computational Biology, 9(2), e1002924) indicates that homodimerization may be important for forming an electrostatic funnel in the spermine synthase homodimer which guides changed substrates toward the active centers. This prompted us to investigate the electrostatic properties of a large set of homodimeric proteins and resulted in an observation that in a vast majority of the cases the dimerization indeed results in specific electrostatic features, although not necessarily in an electrostatic funnel. It is demonstrated that the electrostatic dipole moment of the dimer is predominantly perpendicular to the axis connecting the centers of the mass of the monomers. In addition, the surface points with highest potential are located in the proximity of the interfacial plane of the homodimeric complexes. These findings indicate that frequently homodimerization provides specific electrostatic features needed for the function of proteins.
authors.affiliation: Computational Biophysics and Bioinformatics, Department of Physics, Clemson University, Clemson, SC 29634.
authors.forename: Brandon
authors.initials: B
authors.lastname: Campbell
authors.affiliation: Computational Biophysics and Bioinformatics, Department of Physics, Clemson University, Clemson, SC 29634.
authors.forename: Marharyta
authors.initials: M
authors.lastname: Petukh
authors.affiliation: Computational Biophysics and Bioinformatics, Department of Physics, Clemson University, Clemson, SC 29634.
authors.forename: Emil
authors.initials: E
authors.lastname: Alexov
authors.affiliation: Computational Biophysics and Bioinformatics, Department of Physics, Clemson University, Clemson, SC 29634.
authors.forename: Chuan
authors.initials: C
authors.lastname: Li
keywords: Poisson-Boltzmann equation; electrostatic field; electrostatic funneling; electrostatics; homodimers