What would happen if you delete one amino acid in a particular protein?

It depends upon the protein and also where the deletion of the single amino acid has occurred. Does ur alter or disrupt an important fundamental function or aspect of the protein such as the capability of substrates to bind to the active site, or is near a region that is primarily for developing the additional structure of the protein and is not as important. In most cases, a single amino acid change will not cause the protein to lose its complete function of be denatured.