CORE 1: BIOCHEMISTRY SUMMARY In support of QCRG Pandemic Response Program overall and Project goals, the Biochemistry Core will develop, optimize and execute viral protein expression, purification, and activity assays for structure and functional characterization. This includes suitable presentation of viral proteins in formats for: (1) high resolution structure determination of individual proteins and multi-subunit complexes; (2) screening effective hit and lead compounds; and (3) co-structure determination with hit and lead compounds for structure-based lead optimization and drug discovery. The QCRG Pandemic Response Program Project portfolio currently focuses on proteins from viruses with pandemic potential and proteins that have high potential for druggability. These viruses include 7 species of human coronaviruses (SARS-CoV-2, SARS-CoV, MERS-CoV, OC43, NL63, HKU1, 229E), flaviviruses (dengue, zika), togaviruses (chikungunya virus, Sindbis, Semliki forest, Ross river), and picornaviruses (EV-D68, EV-A71). Specifically, we will provide consistent, high level protein purification of protease (PR) and polymerase (Pol) targets from coronaviruses (e.g. Nsp3, Nsp5, Nsp7, Nsp8, Nsp12) and enteroviruses (e.g. 2A and 3Dpol) (Project 2); E and M coronavirus membrane proteins, and the viroporin '6K' protein from Alphaviruses of the Togaviridae chikungunya, Sindbis, Semliki forest, Ross river (Project 3); coronavirus methyltransferases (e.g. Nsp10, Nsp14, and Nsp16) (Project 4); the macrodomain of Nsp3 from SARS-CoV-2 and chikungunya (Project 5); and N and Orf9b from coronaviruses, and the N protein of zika, dengue, and HPIV3 (Project 6). Having expressed 15 proteins from the 23 coded by SARS-CoV-2 we have established feasibility for these and developed technologies that can be adapted and evolved toward expression and purification for all intended targets from other viruses (for summary see Research Strategy, Table 1).