EC Number |
General Information |
Reference |
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1.14.99.50 | evolution |
EgtB contains a strongly conserved HX3HXE motif, implying that it is a member of the facial triad enzyme family with the Fe(II) site ligated by 2-His-1-Glu |
745390 |
1.14.99.50 | evolution |
enzyme EgtB belongs to the mononuclear nonheme iron dioxygenase family |
-, 745070 |
1.14.99.50 | evolution |
enzyme EgtB represents a distinct enzyme class (sulfoxide synthases) with no relation to sulfur oxidizing or C-S bond-forming iron enzymes such as cysteine dioxygenase or isopenicillin synthase |
733092 |
1.14.99.50 | evolution |
OvoA, EC 1.14.99.52, and EgtB are related in sequence, while they are biochemically distinct |
-, 743388 |
1.14.99.50 | evolution |
Some cyanobacteria recruited and adapted a sulfoxide synthase from a different biosynthetic pathway to make ergothioneine. Evolutionary malleability of the thiohistidine biosynthetic machinery. The sulfoxide synthase EgtB catalyzes the sulfurization of N-alpha-trimethylhistidine at the imidazole 2-position and subsequent oxidation to the S-sulfoxide. The homologous sulfoxide synthases OvoA, EC 1.14.99.52, catalyze the formation of 5-histidylcysteine sulfoxide. The stereochemistry of this sulfoxide is unknown, and cyanobacterial OvoA homologues (Egt-B(ovo)) have evolved to catalyze an EgtB-type reaction by convergent evolution. Prokaryotic EgtBs are usually monofunctional, fungal EgtBs are fused to EgtD |
744709 |
1.14.99.50 | evolution |
the two known sulfoxide synthases EgtB and OvoA distinguish themselves from each other by their substrate preferences and product C-S bond regioselectivity |
-, 734829 |
1.14.99.50 | malfunction |
a single point mutation Y377F converts this enzyme into a gamma-glutamyl cysteine dioxygenase with an efficiency that rivals naturally evolved thiol dioxygenases |
744679 |
1.14.99.50 | metabolism |
biosynthesis of N-alpha-trimethyl-2-thiohistidine (ergothioneine) is a frequent trait in cyanobacteria. This sulfur compound may provide essential relief from oxidative stress related to oxygenic photosynthesis. The central steps in ergothioneine biosynthesis are catalyzed by a histidine methyltransferase and the iron-dependent sulfoxide synthase. Ergothioneine biosynthesis starts by trimethylation of the alpha-amino group of histidine. The resulting N-alpha-trimethylhistidine (TMH) is fused to either gamma-glutamylcysteine (in actinomycetes, EC 1.14.99.50) or cysteine (in fungi, EC 1.14.99.51). The sulfoxide product is converted into ergothoneine by removal of the glutamyl and cysteinyl moieties |
744709 |
1.14.99.50 | metabolism |
EgtB is a nonheme iron enzyme catalyzing the C-S bond formation between gamma-glutamyl cysteine and N-alpha-trimethyl histidine in the ergothioneine biosynthesis |
-, 745070 |
1.14.99.50 | metabolism |
enzyme EgtB catalyzes O2-dependent C-S bond formation between gamma-glutamyl cysteine and N-alpha-trimethyl histidine as the central step in ergothioneine biosynthesis |
733092 |