The catalytic domain of murine terminal deoxynucleotidyl transferase (TdT)
has been crystallized in the space group P2(1)2(1)2(1), with unit-cell para
meters a = 47.1, b = 86.2, c = 111.7 Angstrom. The crystals diffract to a r
esolution of 2.4 Angstrom using synchrotron radiation and a full data set h
as been collected from the native crystals. The enzyme was shown to be acti
ve in the crystalline state.