KEGG   ENZYME: 4.1.99.23Help
Entry
EC 4.1.99.23                Enzyme                                 

Name
5-hydroxybenzimidazole synthase;
bzaF (gene name);
HBI synthase
Class
Lyases;
Carbon-carbon lyases;
Other carbon-carbon lyases
BRITE hierarchy
Sysname
5-amino-1-(5-phospho-beta-D-ribosyl)imidazole formate-lyase (5-hydroxybenzimidazole-forming)
Reaction(IUBMB)
5-amino-1-(5-phospho-beta-D-ribosyl)imidazole + S-adenosyl-L-methionine + reduced acceptor = 5-hydroxybenzimidazole + 5'-deoxyadenosine + L-methionine + formate + NH3 + phosphate + oxidized acceptor [RN:R11919]
Reaction(KEGG)
Substrate
5-amino-1-(5-phospho-beta-D-ribosyl)imidazole [CPD:C03373];
S-adenosyl-L-methionine [CPD:C00019];
reduced acceptor [CPD:C00030]
Product
5-hydroxybenzimidazole [CPD:C21764];
5'-deoxyadenosine [CPD:C05198];
L-methionine [CPD:C00073];
formate [CPD:C00058];
NH3 [CPD:C00014];
phosphate [CPD:C00009];
oxidized acceptor
Comment
The enzyme, purified from bacteria, is part of the anaerobic pathway for cobalamin biosynthesis. It binds a [4Fe-4S] cluster that is coordinated by 3 cysteines and an exchangeable S-adenosyl-L-methionine molecule. The first stage of catalysis is reduction of the S-adenosyl-L-methionine to produce L-methionine and a 5'-deoxyadenosin-5'-yl radical that is crucial for the conversion of the substrate.
History
EC 4.1.99.23 created 2017
Orthology
K22465  5-hydroxybenzimidazole synthase
K22466  5-hydroxybenzimidazole synthase
Genes
GSU: GSU3005(thiC-2)
GSK: KN400_2948(thiC-2)
GME: Gmet_0471(thiC-2)
GUR: Gura_4183
GLO: Glov_3677
GBM: Gbem_3809(thiC-2)
GEO: Geob_0543(thiC-2)
GEM: GM21_3893
GEB: GM18_4239
GPI: GPICK_02630
PPD: Ppro_2809
DES: DSOUD_0618(thiC-2)
DEU: DBW_3101
DSF: UWK_02784
DML: Dmul_38190(thiC2)
DAL: Dalk_0439
DAT: HRM2_06760(thiC)
DTO: TOL2_C39750(thiC2)
DBR: Deba_2032
CACE: CACET_c19200(thiC1) CACET_c19210(thiC2)
AWO: Awo_c14630(thiC2) Awo_c14640(thiC3)
TPZ: Tph_c22270(thiC2) Tph_c22280(thiC3)
 » show all
Taxonomy
Reference
1  [PMID:26237670]
  Authors
Mehta AP, Abdelwahed SH, Fenwick MK, Hazra AB, Taga ME, Zhang Y, Ealick SE, Begley TP
  Title
Anaerobic 5-Hydroxybenzimidazole Formation from Aminoimidazole Ribotide: An Unanticipated Intersection of Thiamin and Vitamin B(1)(2) Biosynthesis.
  Journal
J Am Chem Soc 137:10444-7 (2015)
DOI:10.1021/jacs.5b03576
Reference
2  [PMID:26246619]
  Authors
Hazra AB, Han AW, Mehta AP, Mok KC, Osadchiy V, Begley TP, Taga ME
  Title
Anaerobic biosynthesis of the lower ligand of vitamin B12.
  Journal
Proc Natl Acad Sci U S A 112:10792-7 (2015)
DOI:10.1073/pnas.1509132112
  Sequence
Other DBs
ExplorEnz - The Enzyme Database: 4.1.99.23
IUBMB Enzyme Nomenclature: 4.1.99.23
ExPASy - ENZYME nomenclature database: 4.1.99.23
BRENDA, the Enzyme Database: 4.1.99.23

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