Lu Ming, Sohn Kwang-Jea, Kim Si-Won, Li Chun-Ri, Kim Suhkmann, Kim Dong-Kyoo, Park Jang-Su
Department of Chemistry, Pusan National University, Busan 609-735, Republic of Korea.
Biochem Biophys Res Commun. 2009 Aug 7;385(4):612-7. doi: 10.1016/j.bbrc.2009.05.109. Epub 2009 May 30.
Heat shock factor 1 (HSF1) primarily regulates various cellular stress responses. The role of alpha-helix1 (H1) in its DNA-binding domain (DBD) during HSF1 activation remains unknown. Here, HSF1 lacking H1 loses its heat-induced activity, suggesting the importance of the latter. Furthermore, the CD spectra and AMBER prediction show that this H1 deficiency does not change the structure of HSF1 monomer, but does impact its heat-induced trimerization. Point mutation showed that Phe18 in H1 interacts with Tyr60, and that Trp23 interacts with Phe104 by an aromatic-aromatic interaction. Thus, the presence of H1 stabilizes the DBD structure, which facilitates the heat-induced trimerization and DNA-binding of HSF1.
热休克因子1（HSF1）主要调节各种细胞应激反应。α-螺旋1（H1）在其DNA结合结构域（DBD）中在HSF1激活过程中的作用尚不清楚。在这里，缺乏H1的HSF1失去了其热诱导活性，表明后者的重要性。此外，圆二色光谱（CD光谱）和琥珀色（AMBER）预测表明，这种H1缺陷不会改变HSF1单体的结构，但会影响其热诱导三聚化。点突变表明，H1中的苯丙氨酸18（Phe18）与酪氨酸60（Tyr60）相互作用，色氨酸23（Trp23）通过芳香-芳香相互作用与苯丙氨酸104（Phe104）相互作用。因此，H1的存在稳定了DBD结构，这有利于HSF1的热诱导三聚化和DNA结合。
