UV cross-linking of DNA-protein complexes in vitro

UV cross-linking provides a powerful method to identify proteins that interact with DNA. By using DNA fragments that have been selectively radiolabeled in specific regions of the fragment, it is possible to detect the contacts of specific components in relatively complex mixtures of proteins. Moreover, as many of the functions of DNA are performed by large complexes composed of several multi-subunit proteins, this highly specific strategy of cross-linking can be used to determine the locations of specific polypeptides on the DNA.