Ebola virus VP35 has novel NTPase and helicase-like activities

Shu, Ting; Gan, Tianyu; Bai, Peng; Wang, Xiaotong; Qian, Qi; Zhou, Hui; Cheng, Qi; Qiu, Yang; Yin, Lei; Zhong, Jin; Zhou, Xi

To further characterize the optimal biochemical reaction conditions of EBOV VP35, the purified MBP-VP35 was reacted with the standard RNA helix substrate ( Figure 4A ) under different conditions. We observed that the RNA helix-unwinding activity of MBP-VP35 required the pres-ence of Mg 2+ ( Figure 4B, lane 4) , while the presence of Mn 2+ could also support the helix-unwinding by VP35 in a much lesser extent ( Figure 4B, lane 5) . On the other hand, although Ca 2+ and Zn 2+ have been found to support the NTPase activity of VP35 ( Figure 1D ), these two ions could not support the helix-unwinding activity of VP35 ( Figure 4B, lanes 6 and 7) . Moreover, increasing concentrations of Mg 2+ could promote the helix-unwinding activity of VP35 in a dose-responsive manner ( Figure 4C) . Besides, the optimal helix-unwinding activity of MBP-VP35 was determined to be at pH values of 7-8 ( Figure 4D , lanes 5 and 6), consistent with the optimal pH for the NTPase activity of VP35 ( Figure 1F ).