CRYSTALLIZATION AND PRELIMINARY-X-RAY DIFFRACTION STUDIES ON THE MUTT NUCLEOSIDE TRIPHOSPHATE PYROPHOSPHOHYDROLASE OF ESCHERICHIA-COLI

The mutT nucleoside triphosphatase, which prevents AT-->CG transversions during DNA replication, has been crystallized from ammonium sulfate utilizing a novel technique involving vapor diffusion in capillaries. X-ray diffraction analysis has revealed that the crystals are monoclinic, space group P2(1), with cell constants a = 34.14, b = 72.54, c = 56.38, and beta = 98.90. The V(m) value of 2.31 angstrom3/Da is consistent with two molecules of enzyme per asymmetric unit. The crystals are reasonably stable in the x-ray beam, and a data set to 2.5 angstrom resolution has been collected for native protein. There is evidence that the crystals diffract to at least 2.1 angstrom.