Oh, it's a breakthrough all right, or it could be. Understanding the shape of a protein molecule belonging to a virus can help scientists determine the right "fit" of a drug to block that protein's function. In very basic terms, proteins often work as part of a sort of lock and key system. If a protein vital to the survival and reproduction of a virus is tied up by a drug, then it's no longer able to serve its function, and the virus dies out or at least isn't quite as deadly, assuming the pharmacologist got it right.