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bioRxiv · 10.1101/2021.12.16.473025

In vitro and computational analysis of the putative furin cleavage site (RRARS) in the divergent spike protein of the rodent coronavirus AcCoV-JC34 (sub-genus luchacovirus)

Choi, A.·Singleton, D.·Stout, A.·Millet, J.·Whittaker, G.
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Abstract

The Coronaviridae is a highly diverse virus family, with reservoir hosts in a variety of wildlife species that encompass bats, birds and small mammals, including rodents. Within the taxonomic group alphacoronavirus, certain sub-genera (including the luchacoviruses) have phylogenetically distinct spike proteins, which remain essentially uncharacterized. Using in vitro and computational techniques, we analyzed the spike protein of the rodent coronavirus AcCoV-JC34 from the sub-genus luchacovirus, previously identified in Apodemus chevrieri (Chevriers field mouse). We show that AcCoV-JC34--unlike the other luchacoviruses--has a putative furin cleavage site (FCS) within its spike S1 domain, close to the S1/S2 interface. The pattern of basic amino acids within the AcCoV-JC34 FCS (-RR-R-) is identical to that found in "pre-variant" SARS-CoV-2--which is in itself atypical for an FCS, and suboptimal for furin cleavage. Our analysis shows that, while containing an -RR-R-motif, the AcCoV-JC34 spike "FCS" is not cleaved by furin (unlike for SARS-CoV-2), suggesting the possible presence of a progenitor sequence for viral emergence from a distinct wildlife host.

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Choi, A., Singleton, D., Stout, A., Millet, J., Whittaker, G.. 2021-12-20. In vitro and computational analysis of the putative furin cleavage site (RRARS) in the divergent spike protein of the rodent coronavirus AcCoV-JC34 (sub-genus luchacovirus). https://doi.org/10.1101/2021.12.16.473025

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