biostudies-literatureKrichel BEuropean Research Council1009-1019https://www.ebi.ac.uk/biostudies/studies/S-EPMC7078746biostudies-literatureUnknown477(5)Severe acute respiratory syndrome coronavirus is the causative agent of a respiratory disease with a high case fatality rate. During the formation of the coronaviral replication/transcription complex, essential steps include processing of the conserved polyprotein nsp7-10 region by the main protease Mpro and subsequent complex formation of the released nsp's. Here, we analyzed processing of the coronavirus nsp7-10 region using native mass spectrometry showing consumption of substrate, rise and fall of intermediate products and complexation. Importantly, there is a clear order of cleavage efficiencies, which is influenced by the polyprotein tertiary structure. Furthermore, the predominant product is an nsp7+8(2 : 2) hetero-tetramer with nsp8 scaffold. In conclusion, native MS, opposed to otThe Biochemical journalProcessing of the SARS-CoV pp1a/ab nsp7-10 region.PMC7078746759661Falke SHilgenfeld RRedecke LUetrecht CKrichel BfalseProcessing of the SARS-CoV pp1a/ab nsp7-10 region.Severe acute respiratory syndrome coronavirus is the causative agent of a respiratory disease with a high case fatality rate. During the formation of the coronaviral replication/transcription complex, essential steps include processing of the conserved polyprotein nsp7-10 region by the main protease Mpro and subsequent complex formation of the released nsp's. Here, we analyzed processing of the coronavirus nsp7-10 region using native mass spectrometry showing consumption of substrate, rise and fall of intermediate products and complexation. Importantly, there is a clear order of cleavage efficiencies, which is influenced by the polyprotein tertiary structure. Furthermore, the predominant product is an nsp7+8(2 : 2) hetero-tetramer with nsp8 scaffold. In conclusion, native MS, opposed to ot2020-01-01T00:00:00Z2020 Mar2026-05-01T16:18:51.953Z2026-04-07T17:03:58.77ZS-EPMC70787463208363810.1042/BCJ20200029