Reaction: 2 ATP + NH3 + 7-carboxy-7-carbaguanine = 2 AMP + 2 diphosphate + 7-cyano-7-carbaguanine (overall reaction)
(1a) ATP + 7-carboxy-7-carbaguanine = diphosphate + 7-carboxyadenylyl-7-carbaguanine
(1b) NH3 + 7-carboxyadenylyl-7-carbaguanine = AMP + 7-amido-7-carbaguanine
(1c) ATP + 7-amido-7-carbaguanine = diphosphate + 7-iminomethyladenylyl-7-carbaguanine
(1d) 7-iminomethyladenylyl-7-carbaguanine = AMP + 7-cyano-7-carbaguanine
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
7-carboxyadenylyl-7-carbaguanine = 2-amino-4-oxo-3H,4H,7H-pyrrolo[2,3-d]pyrimidine-5-carboxyadenylate
7-iminomethyladenylyl-7-carbaguanine = 2-amino-4-oxo-3H,4H,7H-pyrrolo[2,3-d]pyrimidine-5-carboximidyl-adenylate
Other name(s): preQ0 synthase; 7-cyano-7-carbaguanine synthase; queC (gene name); toyM (gene name); 7-carboxy-7-carbaguanine:ammonia ligase (ADP-forming)
Systematic name: 7-carboxy-7-carbaguanine:ammonia ligase (AMP-forming)
Comments: Binds Zn2+. The enzyme is found in bacteria and archaea.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number:
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. [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. [PMID: 18491386]
3. Nelp, M.T. and Bandarian, V. A single enzyme transforms a carboxylic acid into a nitrile through an amide intermediate. Angew. Chem. Int. Ed. Engl. 54 (2015) 10627-10629. [PMID: 26228534]