EC Number   |
Substrates |
Organism |
Products |
Reversibility |
|---|
    1.3.98.3 | coproporphyrinogen-III + S-adenosyl-L-methionine |
HemN catalyzes the oxygen-independent conversion of coproporphyrinogen-III to protoporphyrinogen IX, requires S-adenosyl-L-methionine, NAD(P)H and additional cytoplasmatic components for catalysis. Cys-62, Cys-66 and Cys-69 are part of the conserved CXXXCXXC motif and essential for iron-sulfur cluster formation and enzyme function. Gly-111 and Gly-113 are part of the potential GGGTP S-adenosyl-L-methionine binding motif and essential for enzymatic function, catalytic, radical mechanism |
Escherichia coli |
protoporphyrinogen IX + CO2 + L-methionine + 5'-deoxyadenosine |
- |
? |
| 1.3.98.3 | coproporphyrinogen-III + S-adenosyl-L-methionine |
HemN requires the juxtaposition of the [4Fe-4S] cluster and the cosubstrate S-adenosyl-L-methionine. The reaction involves the stereospecific hydrogen abstraction of the pro-S hydrogen from the propionate side chain beta-C of coproporphyrinogen-III, involvement of a coproporphyrinogenyl III radical, which is then decarboxylated releasing CO2 and forming the vinyl group, enzyme structure, two-domain enzyme consisting of the catalytic N- and an alpha-helical C-terminal domain, substrate binding mode |
Escherichia coli |
protoporphyrinogen IX + CO2 + L-methionine + 5'-deoxyadenosine |
- |
? |
| 1.3.98.3 | coproporphyrinogen-III + S-adenosyl-L-methionine |
mechanism, the S-adenosyl-L-methionine sulfonium sulfur is near both the Fe and neighboring sulfur of the cluster allowing single electron transfer from the 4Fe-4S cluster to the S-adenosyl-L-methionine sulfonium. S-adenosyl-L-methionine is cleaved yielding a highly oxidizing 5-deoxyadenosyl radical, HemN binds a second S-adenosyl-L-methionine immediately adjacent to the first and may thus successively catalyze two propionate decarboxylations. Cofactor geometry required for Radical SAM catalysis, detailed enzyme structure, two distinct domains, domain structure, S-adenosyl-L-methionine binding mode |
Escherichia coli |
protoporphyrinogen IX + CO2 + L-methionine + 5'-deoxyadenosine |
- |
? |
| 1.3.98.3 | harderoporphyrinogen + 2 S-adenosyl-L-methionine |
HemN can utilize chemically synthesized harderoporphyrinogen as a substrate and converts it to protoporphyrinogen IX |
Escherichia coli |
protoporphyrinogen IX + 2 CO2 + 2 L-methionine + 2 5'-deoxyadenosine |
- |
? |
| 1.3.98.3 | harderoporphyrinogen + S-adenosyl-L-methionine |
chemical substrate sythesis, overview |
Escherichia coli |
protoporphyrinogen IX + CO2 + L-methionine + 5'-deoxyadenosine |
- |
? |
| 1.3.98.3 | more |
no activity with 1L-chiro-inositol, muco-inositol, allo-inositol, D-glucose, D-glucosamine, D-xylose, 1D-chiro-inositol, and 2,3-dideoxy-scyllo-inosose |
Niallia circulans |
? |
- |
? |
| 1.3.98.3 | more |
HemW shows no coproporphyrinogen III oxidase activity in vivo or in vitro |
Lactococcus lactis |
? |
- |
? |
| 1.3.98.3 | myo-inositol + S-adenosyl-L-methionine |
0.9% activity compared to 2-deoxy-scyllo-inosamine |
Niallia circulans |
? + CO2 + L-methionine + 5'-deoxyadenosine |
- |
? |
| 1.3.98.3 | scyllo-inositol + S-adenosyl-L-methionine |
3.3% activity compared to 2-deoxy-scyllo-inosamine |
Niallia circulans |
? + CO2 + L-methionine + 5'-deoxyadenosine |
- |
? |
