Department of Physics and Center of the Physics of Living Cells, University of Illinois, Urbana, IL 61801, USA.
Structure. 2010 Nov 10;18(11):1443-9. doi: 10.1016/j.str.2010.09.011.
The unconventional motor protein, myosin VI, is known to dimerize upon cargo binding to its C-terminal end. It has been shown that one of its tail domains, called the medial tail domain, is a dimerization region. The domain contains an unusual pattern of alternating charged residues and a few hydrophobic residues. To reveal the unknown dimerization mechanism of the medial tail domain, we employed molecular dynamics and single-molecule experimental techniques. Both techniques suggest that the formation of electrostatic-based interhelical salt bridges between oppositely charged residues is a key dimerization factor. For the dimerization to occur, the two identical helices within the dimer do not bind in a symmetric fashion, but rather with an offset of about one helical repeat. Calculations of the dimer-dissociation energy find the contribution of hydrophobic residues to the dimerization process to be minor; they also find that the asymmetric homodimer state is energetically favorable over a state of separate helices.
非传统的肌球蛋白 VI 分子在其 C 末端与货物结合时会发生二聚化。已经表明，它的一个尾部结构域，称为中尾结构域，是一个二聚化区域。该结构域包含一种不寻常的交替带电荷残基和一些疏水性残基的模式。为了揭示中尾结构域未知的二聚化机制，我们采用了分子动力学和单分子实验技术。这两种技术都表明，在相反电荷残基之间形成基于静电的螺旋间盐桥是二聚化的关键因素。为了发生二聚化，二聚体中的两个相同螺旋不以对称的方式结合，而是有大约一个螺旋重复的偏移。对二聚体解离能的计算发现，疏水性残基对二聚化过程的贡献较小；它们还发现，不对称的同源二聚体状态在能量上优于单独螺旋的状态。
