Isolation and characterization of the Drosophila melanogaster cDNA encoding the sepiapterin reductase

We have isolated and characterized the cDNA encoding Drosophila melanogaste r sepiapterin reductase (SR). The amino acid sequence deduced from the cDNA sequence was 29% identical to those of mammalian SRs. The active site resi dues proposed from the three-dimensional structure of mouse SR are well con served in Drosophila SR. The protein-coding region of the cDNA was expresse d in Escherichia coil as a histidine fusion protein, and the resulting reco mbinant protein proved to have SR activity. The SR activity of the recombin ant protein was inhibited by two indoleamines, N-acetyl serotonin and melat onin, Southern analysis suggests that the Drosophila SR gene is encoded by a single copy gene. RNA blot analysis revealed that the gene expresses 1.5 kb mRNA in both adult heads and bodies. (C) 1998 Elsevier Science B.V. All rights reserved.