Structure-Guided Mutagenesis Alters Deubiquitinating Activity and Attenuates Pathogenesis of a Murine Coronavirus

Xufang Deng; Yafang Chen; Anna M. Mielech; Matthew Hackbart; Kristina R. Kesely; Robert C. Mettelman; Amornrat O’Brien; Mackenzie E. Chapman; Andrew D. Mesecar; Susan C. Baker

We can also use these structural, mutagenesis and kinetic characterization studies on MHV 241 PLP2 to guide future structure-based design studies of emerging coronaviruses, such as the newly We were able to reproduce the enzymatic profile of the purified PLP2-D1772A mutant 256 protein when we expressed it in cell culture (Fig. 3) . Therefore, our finding that the DUBmut virus 257 containing the PLP2-D1772A substitution activates an elevated antiviral response in macrophages 258 compared to the wild-type virus, but that this antiviral state results in only mild attenuation of 259 disease in mice relative to WT infection, was unexpected. Previous studies demonstrated that 260 ubiquitin has important roles in both the activation and the attenuation of innate antiviral pathways 261 (39); therefore, we anticipated a more remarkable phenotype for a DUB-mutant virus. We can 262 imagine several possible explanations for our findings. First, it is possible that viral DUB activity 263 All rights reserved. No reuse allowed without permission.