Lw. Zhong et al., Purification, crystallization and preliminary crystallographic data for rat cytosolic selenocysteine 498 to cysteine mutant thioredoxin reductase, ACT CRYST D, 56, 2000, pp. 1191-1193
Mammalian cytosolic thioredoxin reductase is a homodimer of 55 kDa subunit
containing an essential penultimate selenocysteine residue. An active analo
gue of the rat enzyme in which cysteine replaces selenocysteine has been ex
pressed in Escherichia coli cells at high levels and purified to homogeneit
y. The pure enzyme contains one FAD per subunit and shows spectral properti
es identical to that of the wild-type thioredoxin reductase. The isolated e
nzyme in its oxidized and reduced forms or the enzyme complexed with NADP() was crystallized by the hanging-drop vapour-diffusion method. The diffrac
tion pattern extends to 3 Angstrom resolution. The crystals are monoclinic,
space group P2(1), with unit-cell parameters a = 78.9, b = 140.5, c = 170.
8 Angstrom, alpha = 94.6 degrees. There are three dimeric molecules in the
asymmetric unit.