Number 189 (Story #4), August 9, 1994 by Phillip F. Schewe and Ben Stein THE P53 MOLECULE , a protein whose damaged form is associated with half of all human cancers, has been imaged using x-ray crystallography by Nikola Pavletich and his colleagues at the Memorial Sloan-Kettering Cancer Center in New York. In its normal state, p53 actually prevents the spread of cancer, by halting the division of cells with mistakes in their DNA. But when p53 gets damaged, it can no longer prevent the spread of cancer, and mutated forms of p53 have been found in at least 51 types of human tumors. Pavletich studied the part of p53 responsible for halting cell growth, the part that binds to DNA. Shown at the recent American Crystallographic Association meeting in Atlanta, the new image has 2.2 angstroms resolution and shows exactly where the defects occur on the protein's binding sites. This could enable the development of drugs to repair the damaged sites. However, this task may be complex: researchers believe a different drug may be needed to repair each of the defects on the protein. (Science, 15 July 1994)