molecular lesion

A molecular lesion or point lesion is damage to the structure of a biological molecule such as DNA, enzymes, or proteins that results in reduction or absence of normal function or, in rare cases, the gain of a new function. Lesions in DNA consist of breaks and other changes in the chemical structure of the helix (see types of DNA lesions) while lesions in proteins consist of both broken bonds and improper folding of the amino acid chain.