Department of Chemical Sciences, Ariel University, 40700, Ariel, Israel.
Faculty of Chemistry, Weizmann Institute of Science, 76100, Rehovot, Israel.
Sci Rep. 2020 Jul 22;10(1):12199. doi: 10.1038/s41598-020-68689-6.
A new technique for promoting nucleation and growth of membrane protein (MP) crystals from micellar environments is reported. It relies on the conjugation of micelles that sequester MPs in protein detergent complexes (PDCs). Conjugation via amphiphilic [metal:chelator] complexes presumably takes place at the micelle/water interface, thereby bringing the PDCs into proximity, promoting crystal nucleation and growth. We have successfully applied this approach to two light-driven proton pumps: bacteriorhodopsin (bR) and the recently discovered King Sejong 1-2 (KS1-2), using the amphiphilic 4,4'-dinonyl-2,2'-dipyridyl (Dinonyl) (0.7 mM) chelator in combination with Zn, Fe, or Ni (0.1 mM). Crystal growth in the presence of the [metal-chelator] complexes leads to purple, hexagonal crystals (50-75 µm in size) of bR or pink, rectangular/square crystals (5-15 µm) of KS1-2. The effects of divalent cation identity and concentration, chelator structure and concentration, ionic strength and pH on crystal size, morphology and process kinetics, are described.
一种从胶束环境中促进膜蛋白 (MP) 晶体成核和生长的新技术被报道。它依赖于胶束的共轭，胶束将 MPs 隔离在蛋白洗涤剂复合物 (PDC) 中。通过两亲 [金属:螯合剂] 配合物的共轭可能发生在胶束/水界面，从而使 PDCs 接近，促进晶体成核和生长。我们已经成功地将这种方法应用于两种光驱动质子泵：细菌视紫红质 (bR) 和最近发现的 King Sejong 1-2 (KS1-2)，使用两亲性 4,4'-二壬基-2,2'-联吡啶 (Dinonyl)（0.7 mM）螯合剂与 Zn、Fe 或 Ni（0.1 mM）结合。在 [金属-螯合剂] 配合物的存在下进行晶体生长，得到紫色六方晶体（大小为 50-75 µm）的 bR 或粉色矩形/正方形晶体（大小为 5-15 µm）的 KS1-2。描述了二价阳离子种类和浓度、螯合剂结构和浓度、离子强度和 pH 对晶体大小、形态和过程动力学的影响。
