This view shows enzymes only for those organisms listed below, in the list of taxa known to possess the pathway. If an enzyme name is shown in bold, there is experimental evidence for this enzymatic activity.
Synonyms: IMP biosynthesis I
|Superclasses:||Biosynthesis → Nucleosides and Nucleotides Biosynthesis → Purine Nucleotide Biosynthesis → Purine Nucleotides De Novo Biosynthesis → Purine Riboucleotides De Novo Biosynthesis → Inosine-5'-phosphate Biosynthesis|
Expected Taxonomic Range:
De novo biosynthesis of purines starts with the synthesis of IMP, which can be converted to all other purines.
In bacteria and archaea IMP is synthesized from 5-amino-1-(5-phospho-β-D-ribosyl)imidazole in 6 steps, while in eukarya the first two steps are replaced by a single reaction (see inosine-5'-phosphate biosynthesis II).
The first 4 steps of the bacterial pathway are catalyzed by individual enzymes, and the last two steps are catalyzed by a single multifunctional enzyme, AICAR transformylase / IMP cyclohydrolase, which is encoded by the purH gene.
In archaea the last two steps are catalyzes by two different enzymes (see inosine-5'-phosphate biosynthesis III).
Genetic studies indicate that in bacterial systems the majority of de novo purine biosynthetic genes are unlinked, but may act as a single unit of regulation controlled by the `purR' repressor protein.
Unification Links: EcoCyc:PWY-6123
Neidhardt96: Neidhardt FC, Curtiss III R, Ingraham JL, Lin ECC, Low Jr KB, Magasanik B, Reznikoff WS, Riley M, Schaechter M, Umbarger HE "Escherichia coli and Salmonella, Cellular and Molecular Biology, Second Edition." American Society for Microbiology, Washington, D.C., 1996.
Aiba89: Aiba A, Mizobuchi K (1989). "Nucleotide sequence analysis of genes purH and purD involved in the de novo purine nucleotide biosynthesis of Escherichia coli." J Biol Chem 1989;264(35);21239-46. PMID: 2687276
Alenin92: Alenin VV, Ostanin KV, Kostikova TR, Domkin VD, Zubova VA, Smirnov MN (1992). "[Substrate specificity of phosphoribosyl-aminoimidazole-succinocarboxamide synthetase (SAICAR-synthetase) from Saccharomyces cerevisiae yeast]." Biokhimiia 1992;57(6);845-55. PMID: 1420588
Axelrod08: Axelrod HL, McMullan D, Krishna SS, Miller MD, Elsliger MA, Abdubek P, Ambing E, Astakhova T, Carlton D, Chiu HJ, Clayton T, Duan L, Feuerhelm J, Grzechnik SK, Hale J, Han GW, Haugen J, Jaroszewski L, Jin KK, Klock HE, Knuth MW, Koesema E, Morse AT, Nigoghossian E, Okach L, Oommachen S, Paulsen J, Quijano K, Reyes R, Rife CL, van den Bedem H, Weekes D, White A, Wolf G, Xu Q, Hodgson KO, Wooley J, Deacon AM, Godzik A, Lesley SA, Wilson IA (2008). "Crystal structure of AICAR transformylase IMP cyclohydrolase (TM1249) from Thermotoga maritima at 1.88 A resolution." Proteins 71(2);1042-9. PMID: 18260100
Bulock02: Bulock KG, Beardsley GP, Anderson KS (2002). "The kinetic mechanism of the human bifunctional enzyme ATIC (5-amino-4-imidazolecarboxamide ribonucleotide transformylase/inosine 5'-monophosphate cyclohydrolase). A surprising lack of substrate channeling." J Biol Chem 277(25);22168-74. PMID: 11948179
DiazMejia09: Diaz-Mejia JJ, Babu M, Emili A (2009). "Computational and experimental approaches to chart the Escherichia coli cell-envelope-associated proteome and interactome." FEMS Microbiol Rev 33(1);66-97. PMID: 19054114
Firestine94: Firestine SM, Poon SW, Mueller EJ, Stubbe J, Davisson VJ (1994). "Reactions catalyzed by 5-aminoimidazole ribonucleotide carboxylases from Escherichia coli and Gallus gallus: a case for divergent catalytic mechanisms." Biochemistry 1994;33(39);11927-34. PMID: 7918411
Flannigan90: Flannigan KA, Hennigan SH, Vogelbacker HH, Gots JS, Smith JM (1990). "Purine biosynthesis in Escherichia coli K12: structure and DNA sequence studies of the purHD locus." Mol Microbiol 1990;4(3);381-92. PMID: 2192230
Ginder06: Ginder ND, Binkowski DJ, Fromm HJ, Honzatko RB (2006). "Nucleotide complexes of Escherichia coli phosphoribosylaminoimidazole succinocarboxamide synthetase." J Biol Chem 281(30);20680-8. PMID: 16687397
Hoskins07: Hoskins AA, Morar M, Kappock TJ, Mathews II, Zaugg JB, Barder TE, Peng P, Okamoto A, Ealick SE, Stubbe J (2007). "N5-CAIR mutase: role of a CO2 binding site and substrate movement in catalysis." Biochemistry 46(10);2842-55. PMID: 17298082
Jung10: Jung SC, Smith CL, Lee KS, Hong ME, Kweon DH, Stephanopoulos G, Jin YS (2010). "Restoration of growth phenotypes of Escherichia coli DH5alpha in minimal media through reversal of a point mutation in purB." Appl Environ Microbiol 76(18);6307-9. PMID: 20675450
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