Reaction: ATP + L-glutamine = AMP + diphosphate + 2-amino-4-cyanobutanoate (overall reaction)
(1a) ATP + H2O = AMP + diphosphate
(1b) L-glutamine + AMP = (2S)-5-[(5'-adenylyl)oxy]-5-imino-2-aminopentanoate + H2O
(1c) (2S)-5-[(5'-adenylyl)oxy]-5-imino-2-aminopentanoate = 2-amino-4-cyanobutanoate + AMP
Glossary: 2-amino-4-cyanobutanoate = 3-cyano-L-homoalanine = L-γ-cyanohomoalanine
Other name(s): nitB (gene name); artA (gene name)
Systematic name: L-glutamine hydro-lyase (ATP-hydrolysing, 3-cyano-L-homoalanine-forming)
Comments: The enzyme, charaterized from the fungi Penicillium aurantiocandidum and Aspergillus lentulus, participates in the biosynthesis of the the fungal antimicrobial compound auranthine. It is a member of a family of argininosuccinate synthetase (EC 6.3.4.5)-like nitrile synthases that are widespread in fungi and bacteria. Note that while a water molecule is released from L-glutamine, another one is incorporated during the hydrolysis of ATP, and thus the overall reaction does not include water.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number:
References:
1. Kishimoto, S., Tamura, T., Okamoto, T. and Watanabe, K. Enantioselective biosynthesis of (+)- and (–)-auranthines. J. Am. Chem. Soc. 147 (2025) 10612-10617. [PMID: 40099513]
2. Zeng, Y., Zhang, K., Lu, T., Yin, X., Wang, Q., Xiong, L., Guo, H., Li, J., Lu, X., Liu, L., Ma, H. and Gao, Z. Structural and mechanistic basis for nitrile synthetase by an argininosuccinate synthetase-like enzyme. ACS Catalysis (2025) 16254-16267.