Carlsson Andreas, Olsson Ulf, Linse Sara
Biochemistry and Structural Biology, Chemical Centre, Lund University, Lund, Sweden.
Physical Chemistry, Chemical Centre, Lund University, Lund, Sweden.
QRB Discov. 2023 Aug 15;4:e6. doi: 10.1017/qrd.2023.4. eCollection 2023.
The human chaperone DNAJB6b increases the solubility of proteins involved in protein aggregation diseases and suppresses the nucleation of amyloid structures. Due to such favourable properties, DNAJB6b has gained increasing attention over the past decade. The understanding of how DNAJB6b operates on a molecular level may aid the design of inhibitors against amyloid formation. In this work, fundamental aspects of DNAJB6b self-assembly have been examined, providing a basis for future experimental designs and conclusions. The results imply the formation of large chaperone clusters in a concentration-dependent manner. Microfluidic diffusional sizing (MDS) was used to evaluate how DNAJB6b average hydrodynamic radius varies with concentration. We found that, in 20 mM sodium phosphate buffer, 0.2 mM EDTA, at pH 8.0 and room temperature, DNAJB6b displays a micellar behaviour, with a critical micelle concentration (CMC) of around 120 nM. The average hydrodynamic radius appears to be concentration independent between ∼10 μM and 100 μM, with a mean radius of about 12 nm. The CMC found by MDS is supported by native agarose gel electrophoresis and the size distribution appears bimodal in the DNAJB6b concentration range ∼100 nM to 4 μM.
人伴侣蛋白DNAJB6b可提高与蛋白质聚集疾病相关的蛋白质的溶解度，并抑制淀粉样结构的成核。由于具有这些有利特性，DNAJB6b在过去十年中受到了越来越多的关注。了解DNAJB6b在分子水平上的作用方式可能有助于设计抗淀粉样蛋白形成的抑制剂。在这项工作中，我们研究了DNAJB6b自组装的基本方面，为未来的实验设计和结论提供了基础。结果表明，DNAJB6b以浓度依赖的方式形成大的伴侣蛋白簇。微流控扩散筛分（MDS）用于评估DNAJB6b的平均流体动力学半径如何随浓度变化。我们发现，在pH 8.0、室温下的20 mM磷酸钠缓冲液、0.2 mM EDTA中，DNAJB6b表现出胶束行为，临界胶束浓度（CMC）约为120 nM。在约10 μM至100 μM之间，平均流体动力学半径似乎与浓度无关，平均半径约为12 nm。通过MDS发现的CMC得到了天然琼脂糖凝胶电泳的支持，并且在DNAJB6b浓度范围约100 nM至4 μM内，尺寸分布呈现双峰。
