The presence of a furin-cleavage is favored for infection of SARS-CoV-2 as the cleavage allows the open conformation, exposing the receptor-binding domain (RBD) for easier binding access to a human receptor. The study found that the lower number of S proteins are in a closed conformation for protease-cleaved. There is also an increasing percentage of intermediate form, which is possibly transient, (39%, compared to 34% being closed and 27% being open) demonstrating a high probability that it will shift to an open form and allow binding to a receptor. Therefore, protease cleavage is favored not only for membrane fusion but also for better binding to a receptor by increasing the proportion of S protein on the virus surface.