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Free keywords:
ESCHERICHIA-COLI; N-5-CARBOXYAMINOIMIDAZOLE RIBONUCLEOTIDE;
THERMOTOGA-MARITIMA; SAICAR SYNTHASE; GALLUS-GALLUS; MUTASE PURE;
CARBOXYLASES; PATHWAY; SITEpurine biosynthesis; PAICS; PurE; 5-aminoimidazole ribonucleotide
carboxylase; 4-(N-succinylcarboxamide)-5-aminoimidazole ribonucleotide
synthetase; SAICAR; crystal structure;
Abstract:
Two important steps of the de novo purine biosynthesis pathway are catalyzed by the 5-aminoimidazole ribonucleotide carboxylase and the 4-(N-succinylcarboxamide)-5-aminoimidazole ribonucleotide synthetase enzymes. In most eukaryotic organisms, these two activities are present in the bifunctional enzyme complex known as PAICS. We have determined the 2.8-angstrom resolution crystal structure of the 350-kDa invertebrate PAICS from insect cells (Trichoplusia ni) using single-wavelength anomalous dispersion methods. Comparison of insect PAICS to human and prokaryotic homologs provides insights into substrate binding and reveals a highly conserved enzymatic framework across divergent species. Proteins 2013; 81:1473-1478. (c) 2013 Wiley Periodicals, Inc.
