Crystallographic investigations of the tryptophan‐derived cofactor in the quinoprotein methylamine dehydrogenase

Abstract
A model of tryptophan tryptophylquinone (TTQ), recently proposed by Mclntire et al. (Science (1991) 252, 817-824) to be the prosthetic group of the quinoprotein methylamine dehydrogenase, has been compared with electron density maps of this dehydrogenase from Thiobacillus versutus and Paracoccus denitrificans . The comparison shows that the TTQ model can be neatly accommodated, providing strong supportive evidence that TTQ is indeed the cofactor for this group of quinoproteins.