Three-dimensional structure of the inosine-uridine nucleoside N-ribohydrolase from Crithidia fasciculata

The three-dimensional structure of inosine-uridine nucleoside N-ribohydrolase from Crithidia fasciculata is resolved using X-ray crystallography. The protein comprises an eight-stranded beta-sheet and six alpha-helices. The catalytic site is situated at the C-terminal end of beta-strands beta-1 and beta-4. The part of the catalytic site envisaged to be involved in purine salvage is hydrophobic and contains a single ionizable histidine. The substrate binding site has a novel architecture.