title: Crystal structure of the invertebrate bifunctional purine biosynthesis enzyme PAICS at 2.8 Å resolution.
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-Å 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.
authors.affiliation: Max-Planck-Institute of Biochemistry, Department of Structural Cell Biology, Martinsried, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Taschner
authors.forename: Jérôme
authors.initials: J
authors.lastname: Basquin
authors.forename: Christian
authors.initials: C
authors.lastname: Benda
authors.forename: Esben
authors.initials: E
authors.lastname: Lorentzen
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002262:Carboxy-Lyases / Q000737:chemistry* / Q000378:metabolism; D018360:Crystallography, X-Ray; D006801:Humans; D019476:Insect Proteins / Q000737:chemistry* / Q000378:metabolism; D008969:Molecular Sequence Data; D009036:Moths / Q000737:chemistry / Q000201:enzymology*; D011687:Purines / Q000378:metabolism*; D016415:Sequence Alignment
chemical_list: D019476:Insect Proteins; D011687:Purines; D002262:Carboxy-Lyases; C022378:phosphoribosylaminoimidazole carboxylase; C030985:purine
keywords: 4-(N-succinylcarboxamide)-5-aminoimidazole ribonucleotide synthetase; 5-aminoimidazole ribonucleotide carboxylase; PAICS; PurE; SAICAR; crystal structure; purine biosynthesis