| EC |
4.3.99.3 |
| Accepted name: |
7-carboxy-7-deazaguanine synthase |
| Reaction: |
6-carboxy-5,6,7,8-tetrahydropterin = 7-carboxy-7-carbaguanine + NH3 |
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For diagram of queuine biosynthesis, click here |
| Glossary: |
7-carboxy-7-carbaguanine = 7-carboxy-7-deazaguanine |
| Other name(s): |
7-carboxy-7-carbaguanine synthase; queE (gene name) |
| Systematic name: |
6-carboxy-5,6,7,8-tetrahydropterin ammonia-lyase |
| Comments: |
Requires Mg2+. The enzyme is a member of the superfamily of S-adenosyl-L-methionine-dependent radical (radical AdoMet) enzymes. Binds a [4Fe-4S] cluster that is coordinated by 3 cysteines and an exchangeable S-adenosyl-L-methionine molecule. The S-adenosyl-L-methionine is catalytic as it is regenerated at the end of the reaction. The reaction is part of the biosynthesis pathway of queuosine. |
| Links to other databases: |
BRENDA, EXPASY, KEGG, MetaCyc, PDB |
| References: |
| 1. |
McCarty, R.M., Somogyi, A., Lin, G., Jacobsen, N.E. and Bandarian, V. The deazapurine biosynthetic pathway revealed: in vitro enzymatic synthesis of preQ0 from guanosine 5′-triphosphate in four steps. Biochemistry 48 (2009) 3847–3852. [DOI] [PMID: 19354300] |
| 2. |
McCarty, R.M., Krebs, C. and Bandarian, V. Spectroscopic, steady-state kinetic, and mechanistic characterization of the radical SAM enzyme QueE, which catalyzes a complex cyclization reaction in the biosynthesis of 7-deazapurines. Biochemistry 52 (2013) 188–198. [DOI] [PMID: 23194065] |
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| [EC 4.3.99.3 created 2012] |
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| EC |
6.3.4.20 |
| Accepted name: |
7-cyano-7-deazaguanine synthase |
| Reaction: |
7-carboxy-7-carbaguanine + NH3 + ATP = 7-cyano-7-carbaguanine + ADP + phosphate + H2O |
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For diagram of queuine biosynthesis, click here |
| Glossary: |
preQ0 = 7-cyano-7-carbaguanine = 7-cyano-7-deazaguanine
7-carboxy-7-carbaguanine = 7-carboxy-7-deazaguanine |
| Other name(s): |
preQ0 synthase; 7-cyano-7-carbaguanine synthase; queC (gene name) |
| Systematic name: |
7-carboxy-7-carbaguanine:ammonia ligase (ADP-forming) |
| Comments: |
Binds Zn2+. The reaction is part of the biosynthesis pathway of queuosine. |
| Links to other databases: |
BRENDA, EXPASY, KEGG, MetaCyc, PDB |
| References: |
| 1. |
McCarty, R.M., Somogyi, A., Lin, G., Jacobsen, N.E. and Bandarian, V. The deazapurine biosynthetic pathway revealed: in vitro enzymatic synthesis of preQ0 from guanosine 5′-triphosphate in four steps. Biochemistry 48 (2009) 3847–3852. [DOI] [PMID: 19354300] |
| 2. |
Cicmil, N. and Huang, R.H. Crystal structure of QueC from Bacillus subtilis: an enzyme involved in preQ1 biosynthesis. Proteins 72 (2008) 1084–1088. [DOI] [PMID: 18491386] |
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| [EC 6.3.4.20 created 2012] |
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