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Literature summary for 4.1.1.111 extracted from

  • Kühner, M.; Haufschildt, K.; Neumann, A.; Storbeck, S.; Streif, J.; Layer, G.
    The alternative route to heme in the methanogenic archaeon Methanosarcina barkeri (2014), Archaea, 2014, 327637.
    View publication on PubMedView publication on EuropePMC
Search for more literature for 4.1.1.111

Activating Compound

Activating Compound Comment Organism Structure
Dithionite the haem bound to the AhbA/B complex must be reduced in order for the enzyme to be most active. Treatment with excess dithionite results in a 6.5fold increase in the activity of the enzyme Desulfovibrio desulfuricans
Dithionite the heme bound to the AhbA/B complex must be reduced in order for the enzyme to be most active. Treatment with excess dithionite results in a 6.5fold increase in the activity of the enzyme Methanosarcina barkeri

Cloned(Commentary)

Cloned (Comment) Organism
proteins ahbA and ahbB are cloned into distinct plasmids and expressed separately in Escherichia coli. When expressed individually the encoded proteins are highly unstable and can only be purified at very low concentrations due to their tendency to precipitate Desulfovibrio desulfuricans

Crystallization (Commentary)

Crystallization (Comment) Organism
hanging drop vapour diffusion crystallization at 19°C Desulfovibrio desulfuricans

General Stability

General Stability Organism
subunits AhbA and AhbB have a stabilizing effect on each other by forming a complex Desulfovibrio desulfuricans

Inhibitors

Inhibitors Comment Organism Structure
monodecarboxysiroheme single active site with a competitive inhibition model for siroheme and monodecarboxysiroheme Desulfovibrio desulfuricans
siroheme single active site with a competitive inhibition model for siroheme and monodecarboxysiroheme Desulfovibrio desulfuricans

Molecular Weight [Da]

Molecular Weight [Da] Molecular Weight Maximum [Da] Comment Organism
44000
-
 heterodimeric complex of subunits AhbA and AhbB, gel filtration Desulfovibrio desulfuricans
94000
-
 heterotetrameric complex of subunits AhbA and AhbB, gel filtration Desulfovibrio desulfuricans

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
siroheme Desulfovibrio desulfuricans
-
 12,18-didecarboxysiroheme + 2 CO2
-
 ?
siroheme Methanosarcina barkeri the enzyme is involved in the alternative heme biosynthesis pathway (in bacteria and archaea) 12,18-didecarboxysiroheme + 2 CO2
-
 ?
siroheme Desulfovibrio desulfuricans DSM 6949
-
 12,18-didecarboxysiroheme + 2 CO2
-
 ?

Organism

Organism UniProt Comment Textmining
Desulfovibrio desulfuricans B8J364
-
-
Desulfovibrio desulfuricans DSM 6949 B8J364
-
-
Methanosarcina barkeri
-
-
-

Purification (Commentary)

Purification (Comment) Organism
proteins ahbA and ahbB are cloned into distinct plasmids and expressed separately in Escherichia coli. When expressed individually the encoded proteins are highly unstable and can only be purified at very low concentrations due to their tendency to precipitate Desulfovibrio desulfuricans

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
siroheme
-
 Methanosarcina barkeri 12,18-didecarboxysiroheme + 2 CO2
-
 ?
siroheme
-
 Desulfovibrio desulfuricans 12,18-didecarboxysiroheme + 2 CO2
-
 ?
siroheme the enzyme is involved in the alternative heme biosynthesis pathway (in bacteria and archaea) Methanosarcina barkeri 12,18-didecarboxysiroheme + 2 CO2
-
 ?
siroheme incubations of individual AhbA and AhbB proteins in excess with sirohaem yields mixtures with varying levels of siroheme, monodecarboxysiroheme and didecarboxysiroheme. The monodecarboxysiroheme is not characterized further and hence it is not determined as to whether it is due to loss of the carboxylic acid from the C12 or C18 side-chain. The individual subunits, AhbA and AhbB, are capable of decarboxylating siroheme by themselves. The individual subunits form homodimers, which likely represents the active species Desulfovibrio desulfuricans 12,18-didecarboxysiroheme + 2 CO2
-
 ?
siroheme
-
 Desulfovibrio desulfuricans DSM 6949 12,18-didecarboxysiroheme + 2 CO2
-
 ?
siroheme incubations of individual AhbA and AhbB proteins in excess with sirohaem yields mixtures with varying levels of siroheme, monodecarboxysiroheme and didecarboxysiroheme. The monodecarboxysiroheme is not characterized further and hence it is not determined as to whether it is due to loss of the carboxylic acid from the C12 or C18 side-chain. The individual subunits, AhbA and AhbB, are capable of decarboxylating siroheme by themselves. The individual subunits form homodimers, which likely represents the active species Desulfovibrio desulfuricans DSM 6949 12,18-didecarboxysiroheme + 2 CO2
-
 ?

Subunits

Subunits Comment Organism
heterodimer composed of AhbA and AhbB Methanosarcina barkeri
heterodimer the individual subunits, AhbA and AhbB, are capable of decarboxylating sirohaem by themselves. The individual subunits form homodimers, which likely represents the active species. Subunits AhbA and AhbB have a stabilizing effect on each other by forming a complex Desulfovibrio desulfuricans

Synonyms

Synonyms Comment Organism
AhbA/B
-
 Methanosarcina barkeri
sirohaem decarboxylase
-
 Methanosarcina barkeri

Cofactor

Cofactor Comment Organism Structure
heme the heme bound to the AhbA/B complex must be reduced in order for the enzyme to be most active. Treatment with excess dithionite results in a 6.5fold increase in the activity of the enzyme Methanosarcina barkeri

General Information

General Information Comment Organism
physiological function the enzyme is involved in the alternative heme biosynthesis pathway (in bacteria and archaea) Desulfovibrio desulfuricans
physiological function the enzyme is involved in the alternative heme biosynthesis pathway (in bacterioa and archaea) Methanosarcina barkeri