UMMS Affiliation

Program in Molecular Medicine; Department of Microbiology and Physiological Systems; Department of Biochemistry and Molecular Pharmacology; Graduate School of Biomedical Sciences

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Article Preprint


Amino Acids, Peptides, and Proteins | Genetics and Genomics | Immunology and Infectious Disease | Infectious Disease | Microbiology | Nucleic Acids, Nucleotides, and Nucleosides | Virus Diseases


Virus genome sequence variants that appear over the course of an outbreak can be exploited to map the trajectory of the virus from one susceptible host to another. While such variants are usually of no functional significance, in some cases they may allow the virus to transmit faster, change disease severity, or confer resistance to antiviral therapies. Since the discovery of SARS-CoV-2 as the cause of COVID-19, the virus has spread around the globe, and thousands of SARS-CoV-2 genomes have been sequenced. The rate of sequence variation among SARS-CoV-2 isolates is modest for an RNA virus but the enormous number of human-to-human transmission events has provided abundant opportunity for selection of sequence variants. Among these, the SARS-CoV-2 Spike protein variant, D614G, was not present in the presumptive common ancestor of this zoonotic virus, but was first detected in late January in Germany and China. The D614G variant steadily increased in frequency and now constitutes >97% of isolates world-wide, raising the question whether D614G confers a replication advantage to SARS-CoV-2. Structural models predict that D614G would disrupt contacts between the S1 and S2 domains of the Spike protein and cause significant shifts in conformation. Using single-cycle vectors we showed that D614G is three to nine-fold more infectious than the ancestral form on human lung and colon cell lines, as well as on other human cell lines rendered permissive by ectopic expression of human ACE2 and TMPRSS2, or by ACE2 orthologues from pangolin, pig, dog, or cat. Nonetheless, monoclonal antibodies targeting the receptor binding domain of the SARS-CoV-2 Spike protein retain full neutralization potency. These results suggest that D614G was selected for increased human-to-human transmission, that it contributed to the rapidity of SARS-CoV-2 spread around the world, and that it does not confer resistance to antiviral therapies targeting the receptor binding domain.


SARS-CoV-2, COVID-19, microbiology, proteins, antibodies, virus genome sequence variants, D614G

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The copyright holder for this preprint (which was not peer-reviewed) is the author/funder. It is made available under a CC-BY-NC-ND 4.0 International license.

DOI of Published Version



bioRxiv 2020.07.04.187757; doi: 10.1101/2020.07.04.187757. Link to preprint on bioRxiv

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The PDF available for download is Version 1 of this preprint. The complete version history of this preprint is available at bioRxiv.

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Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.