Rogers S S, Venema P, van der Ploeg J P M, van der Linden E, Sagis L M C, Donald A M
Cavendish Laboratory, Department of Physics, Cambridge University, Cambridge, CB3 0HE, UK.
Biopolymers. 2006 Jun 15;82(3):241-52. doi: 10.1002/bip.20483.
Amyloid fibrils, which are polymeric assemblies of protein molecules, have been intensively studied on a structural level, yet due to complications such as the disorder within the molecules, several aspects of their structure remain mysterious. Similarly, the kinetics of assembly are not well understood. Here we investigate the electric dipole moment of beta-lactoglobulin fibrils, a model amyloid fibril system, by applying the technique of transient electric birefringence. This moment appears to be large, and comparable to the total moment of the constituent protein monomers if they were joined in a chain, head-to-tail, without changing conformation, suggesting an ordered joining of monomers in the fibril. Such an ordered assembly may have implications for the assembly mechanism of beta-lactoglobulin fibrils in particular, and amyloid fibrils in general.
淀粉样纤维是蛋白质分子的聚合物聚集体，已在结构层面进行了深入研究，但由于分子内无序等复杂情况，其结构的几个方面仍然神秘。同样，组装动力学也尚未得到很好的理解。在这里，我们通过应用瞬态电双折射技术研究了β-乳球蛋白纤维（一种模型淀粉样纤维系统）的电偶极矩。这个偶极矩似乎很大，并且如果组成蛋白单体以首尾相连的方式连接成链且不改变构象，那么它与这些单体的总偶极矩相当，这表明纤维中单体的有序连接。这种有序组装可能对β-乳球蛋白纤维的组装机制尤其有影响，对一般的淀粉样纤维也有影响。
