Caulobacter crescentus CB15 Pathway: superpathway of guanosine nucleotides de novo biosynthesis II
Inferred by computational analysis

Pathway diagram: superpathway of guanosine nucleotides de novo biosynthesis II

If an enzyme name is shown in bold, there is experimental evidence for this enzymatic activity.

Locations of Mapped Genes:

Schematic showing all replicons, marked with selected genes

Superclasses: BiosynthesisNucleosides and Nucleotides BiosynthesisPurine Nucleotide BiosynthesisPurine Nucleotides De Novo Biosynthesis

Pathway Summary from MetaCyc:
The first purine nucleotide that is synthesized de novo is IMP (IMP). IMP is converted to XMP (XMP) by the enzyme IMP dehydrogenase, and the later is converted to the first guanosine nucleotide, GMP (GMP), by the action of GMP synthetase, an enzyme that can use either glutamine or ammonia as substrate. GMP is then converted to GDP (GDP) and subsequently to GTP (GTP) by the enzymes guanylate kinase and nucleoside diphosphate kinase, respectively.

In Escherichia coli both GDP and GTP can be converted to the deoxy forms of the nucleotide. GTP is converted to dGTP (dGTP) by the uncommon enzyme ribonucleoside-triphosphate reductase, while GDP can be converted to dGDP (dGDP) by either ribonucleoside diphosphate reductase 1 or ribonucleoside-diphosphate reductase 2.

Finally, nucleoside diphosphate kinase can also convert dGDP to dGTP.

In bacterial systems genetic studies indicate that 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 [Meng90].

Superpathways: superpathway of purine nucleotides de novo biosynthesis II

Subpathways: guanosine deoxyribonucleotides de novo biosynthesis II, guanosine ribonucleotides de novo biosynthesis

Variants: superpathway of adenosine nucleotides de novo biosynthesis I, superpathway of adenosine nucleotides de novo biosynthesis II, superpathway of guanosine nucleotides de novo biosynthesis I, superpathway of purine nucleotides de novo biosynthesis I

Created in MetaCyc 13-Jan-2009 by SRI International
Imported from MetaCyc 18-Sep-2013 by Fulcher CA, SRI International


Meng90: Meng LM, Kilstrup M, Nygaard P (1990). "Autoregulation of PurR repressor synthesis and involvement of purR in the regulation of purB, purC, purL, purMN and guaBA expression in Escherichia coli." Eur J Biochem 1990;187(2);373-9. PMID: 2404765

Other References Related to Enzymes, Genes, Subpathways, and Substrates of this Pathway

Dyson90: Dyson HJ, Gippert GP, Case DA, Holmgren A, Wright PE (1990). "Three-dimensional solution structure of the reduced form of Escherichia coli thioredoxin determined by nuclear magnetic resonance spectroscopy." Biochemistry 1990;29(17);4129-36. PMID: 2193685

Eklund84: Eklund H, Cambillau C, Sjoberg BM, Holmgren A, Jornvall H, Hoog JO, Branden CI (1984). "Conformational and functional similarities between glutaredoxin and thioredoxins." EMBO J 1984;3(7);1443-9. PMID: 6378624

Gleason88: Gleason FK, Holmgren A (1988). "Thioredoxin and related proteins in procaryotes." FEMS Microbiol Rev 1988;4(4);271-97. PMID: 3152490

Gleason90: Gleason FK, Lim CJ, Gerami-Nejad M, Fuchs JA (1990). "Characterization of Escherichia coli thioredoxins with altered active site residues." Biochemistry 1990;29(15);3701-9. PMID: 2187529

Green04: Green ML, Karp PD (2004). "A Bayesian method for identifying missing enzymes in predicted metabolic pathway databases." BMC Bioinformatics 5;76. PMID: 15189570

Holmgren85: Holmgren A (1985). "Thioredoxin." Annu Rev Biochem 1985;54;237-71. PMID: 3896121

Katti90: Katti SK, LeMaster DM, Eklund H (1990). "Crystal structure of thioredoxin from Escherichia coli at 1.68 A resolution." J Mol Biol 1990;212(1);167-84. PMID: 2181145

Nikkola93: Nikkola M, Gleason FK, Fuchs JA, Eklund H (1993). "Crystal structure analysis of a mutant Escherichia coli thioredoxin in which lysine 36 is replaced by glutamic acid." Biochemistry 1993;32(19);5093-8. PMID: 8098620

Setif01: Setif P (2001). "Ferredoxin and flavodoxin reduction by photosystem I." Biochim Biophys Acta 1507(1-3);161-79. PMID: 11687213

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