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 Biology9(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 frequent homodimerization provides specific electrostatic features needed for the function of proteins.

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关于同源二聚体蛋白的静电特性

大部分蛋白质作为同源二聚体发挥作用，但并不总是清楚为什么二聚化对功能很重要，因为通常每个单体都具有独特的活性位点。最近的工作 (PLoS Computational Biology9(2):e1002924) 表明，同二聚体可能对在精胺合酶同二聚体中形成静电漏斗很重要，该静电漏斗将改变的底物引导向活性中心。这促使我们研究大量同源二聚体蛋白质的静电特性，并观察到在绝大多数情况下，二聚化确实导致特定的静电特征，尽管不一定在静电漏斗中。证明二聚体的静电偶极矩主要垂直于连接单体质心的轴。此外，具有最高电位的表面点位于同二聚体配合物的界面平面附近。这些发现表明频繁的同源二聚化提供了蛋白质功能所需的特定静电特征。