Department of Biochemistry, Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran.
Department of Drug Design, University of Groningen, Groningen, The Netherlands.
PLoS One. 2020 May 19;15(5):e0232953. doi: 10.1371/journal.pone.0232953. eCollection 2020.
The unpleasant smell released from dead bodies, may serve as an alarm for avoiding certain behaviour or as feeding or oviposition attractants for animals. However, little is known about their effect on the structure and function of proteins. Previously, we reported that using the aroma form of TEMED (a diamine), representative of the "smell of death", could completely inhibit the fibril formation of HEWL, as an antibacterial enzyme, and a model protein for fibrillation studies. To take this further, in this study we investigated the kinetics of TEMED using a number of techniques and in particular X-ray crystallography to identify the binding site(s) of TEMED and search for hotspot(s) necessary to inhibit fibril formation of HEWL. Structural data, coupled with other experimental data reported in this study, revealed that TEMED completely inhibited fibril formation and stabilized the structure of HEWL through enhancement of the CH-Π interaction and binding to an inhibitor hotspot comprised of residues Lys33, Phe34, Glu35 and Asn37 of HEWL. Additionally, results from this study showed that the binding of TEMED increased the activity and thermal stability of HEWL, helping to improve the function of this antibacterial enzyme. In conclusion, the role of the "smell of death", as an important signal molecule affecting the activity and stability of HEWL was greatly highlighted, suggesting that aroma producing small molecules can be signals for structural and functional changes in proteins.
从尸体中释放出的难闻气味可能是一种避免某些行为的警报，也可能是动物觅食或产卵的吸引剂。然而，人们对它们对蛋白质结构和功能的影响知之甚少。此前，我们报道过使用 TEMED（一种二胺）的香气形式（代表“死亡的味道”）可以完全抑制 HEWL（一种抗菌酶和纤维形成研究的模型蛋白）的纤维形成。为了进一步研究，在这项研究中，我们使用了多种技术，特别是 X 射线晶体学来研究 TEMED 的动力学，以确定 TEMED 的结合位点，并寻找抑制 HEWL 纤维形成所需的热点。结构数据与本研究中报告的其他实验数据相结合，表明 TEMED 通过增强 CH-Π 相互作用并与包含 HEWL 残基 Lys33、Phe34、Glu35 和 Asn37 的抑制剂热点结合，完全抑制纤维形成并稳定 HEWL 的结构。此外，这项研究的结果表明，TEMED 的结合增加了 HEWL 的活性和热稳定性，有助于提高这种抗菌酶的功能。总之，“死亡的味道”作为一种影响 HEWL 活性和稳定性的重要信号分子的作用得到了极大的强调，这表明产生气味的小分子可以作为蛋白质结构和功能变化的信号。
