Why worrisome coronavirus mutations may soon hit their limit

All three variants are troubling because of a change to the “spike” protein that allows the virus to latch on to humans’ ACE-2 receptor and enter human cells more easily, making it more transmissible. And the Brazilian and South African variants carry an additional mutation which diminishes the ability of antibodies to bind to and neutralize the virus, possibly rendering previous infection and vaccines less effective, Khullar writes. There is good news, though — at least in the eyes of Jason McLellan, a structural biologist at the University of Texas at Austin, who believes such mutations may be few and far between going forward.

“There’s just not a lot of space for the spike to continue to change in ways that allow it to evade antibodies but still bind to its receptor,” McLellan told Khullar. “Substitutions that allow the virus to resist antibodies will probably also decrease its affinity for ACE-2,” he continued, adding that because the variants “have independently hit on the same mutations” it’s likely “we’re already seeing the limits of where the virus can go.”