zlacker

The furin cleavage site in SARS-Cov-2 does not appear in any other SARS-related beta coronavirus (sarbecovirus).

>>reuben+(OP)
From 2014, Host cell entry of Middle East respiratory syndrome coronavirus after two-step, furin-mediated activation of the spike protein [1]:

> Such furin-mediated activation is unusual in that it occurs in part during virus entry. Our findings may explain the polytropic nature, pathogenicity, and life cycle of this zoonotic coronavirus.

MERS-CoV uses furin cleavage of S1/S2 but it does not bind to ACE2 like SARS-CoV-2.

[1] https://www.pnas.org/content/111/42/15214