{"doi":"10.1101/2020.06.14.150607","title":"Characterization of the SARS-CoV-2 S Protein: Biophysical, Biochemical, Structural, and Antigenic Analysis","abstract":"ABSTRACT Coronavirus disease 2019 ( COVID-19 ) is a global health crisis caused by the novel severe acute respiratory syndrome coronavirus 2 ( SARS-CoV-2 ), and there is a critical need to produce large quantities of high-quality SARS-CoV-2 Spike ( S ) protein for use in both clinical and basic science settings. To address this need, we have evaluated the expression and purification of two previously reported S protein constructs in Expi293F ™ and ExpiCHO-S ™ cells, two different cell lines selected for increased expression of secreted glycoproteins. We show that ExpiCHO-S ™ cells produce enhanced yields of both SARS-CoV-2 S proteins. Biochemical, biophysical, and structural ( cryo-EM ) characterization of the SARS-CoV-2 S proteins produced in both cell lines demonstrate that the reported purification strategy yields high quality S protein (non-aggregated, uniform material with appropriate biochemical and biophysical properties). Importantly, we show that multiple preparations of these two recombinant S proteins from either cell line exhibit identical behavior in two different serology assays. We also evaluate the specificity of S protein-mediated host cell binding by examining interactions with proposed binding partners in the human secretome. In addition, the antigenicity of these proteins is demonstrated by standard ELISAs, and in a flexible protein microarray format. Collectively, we establish an array of metrics for ensuring the production of high-quality S protein to support clinical, biological, biochemical, structural and mechanistic studies to combat the global pandemic caused by SARS-CoV-2.","journal":"bioRxiv (Cold Spring Harbor Laboratory)","year":2020,"id":118935,"datarank":0.5333022092234121,"base_score":3.5553480614894135,"endowment":3.5553480614894135,"self_citation_contribution":0.5333022092234121,"citation_network_contribution":0.0,"self_endowment_contribution":0.5333022092234121,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":34,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9333,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2020-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":230346,"name":"Nicholas C. 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Noble","orcid":"0000-0001-8634-2279","position":10,"is_corresponding":false},{"id":258060,"name":"Mykhailo Kopylov","orcid":"0000-0003-0188-9799","position":11,"is_corresponding":false},{"id":475732,"name":"J.B. Bonanno","orcid":"0000-0003-0863-7826","position":12,"is_corresponding":false},{"id":475729,"name":"Sarah C. Garrett-Thomson","orcid":"0000-0002-3073-1571","position":13,"is_corresponding":false},{"id":552494,"name":"David Hayes","orcid":"0000-0002-1133-3471","position":14,"is_corresponding":false},{"id":109540,"name":"Robert H. Bortz","orcid":"0000-0003-1751-2152","position":15,"is_corresponding":false},{"id":109541,"name":"Ariel S. 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