Functions Of SARS-CoV-2 NSP13 Helicase: Replication, Transcription, And Suppression Of Natural Immunity A new study sheds light on one of the roles SARS-CoV-2 NSP13 (nonstructural protein 13) plays in the virus' initial attack on the immune system, which is to degrade a kinase enzyme upstream of interferon, TBK1 (TANK-binding kinase 1).