| Abstract
| - One of the functions of MutY from Escherchia coli is removal of adenine mispaired with7,8-dihydro-8-oxoguanine (8-oxoG), a common lesion in oxidatively damaged DNA. MutY is composedof two domains: the larger N-terminal domain (p26) contains the catalytic properties of the enzyme whilethe C-terminal domain (p13) affects substrate recognition and enzyme turnover. On the basis of sequenceanalyses, it has been recently suggested that the C-terminal domain is distantly related to MutT, a dNTPasewhich hydrolyzes 8-oxo-dGTP [Noll et al. (1999) Biochemistry38, 6374−6379]. We have studied thesolution structure of the C-terminal domain of MutY by NMR and find striking similarity with the reportedsolution structure of MutT. Despite low sequence identity between the two proteins, they have similarsecondary structure and topology. The C-terminal domain of MutY is composed of two α-helices andfive β-strands. The NOESY data indicate that the protein has two β-sheets. MutT is also a mixed α/βprotein with two helices and two β-sheets composed of five strands. The secondary structure elementsare similarly arranged in the two proteins.
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