Q46FL0 · CBIA_METBF

Function

function

Catalyzes the ATP-dependent amidation of the two carboxylate groups at positions a and c of cobyrinate, using either L-glutamine or ammonia as the nitrogen source (Potential). Involved in the biosynthesis of the unique nickel-containing tetrapyrrole coenzyme F430, the prosthetic group of methyl-coenzyme M reductase (MCR), which plays a key role in methanogenesis and anaerobic methane oxidation (PubMed:28225763).
Catalyzes the ATP-dependent amidation of the two carboxylate groups at positions a and c of Ni-sirohydrochlorin, using L-glutamine or ammonia as the nitrogen source (PubMed:28225763).
Also able to use sirohydrochlorin as substrate, but only produces a monoamide species in a much slower reaction (PubMed:28225763).
Unable to use other metallosirohydrochlorins such as sirohaem and Co-sirohydrochlorin (PubMed:28225763).

Miscellaneous

The a and c carboxylates of cobyrinate and Ni-sirohydrochlorin are activated for nucleophilic attack via formation of a phosphorylated intermediate by ATP. CbiA catalyzes first the amidation of the c-carboxylate, and then that of the a-carboxylate.

Catalytic activity

Cofactor

Mg2+ (UniProtKB | Rhea| CHEBI:18420 )

Kinetics

KM SUBSTRATE pH TEMPERATURE[C] NOTES EVIDENCE
46 μML-glutamine
28 μMATP
kcat is 1.03 min-1 for ATP as substrate. kcat is 0.78 min-1 for L-glutamine as substrate.

Pathway

Cofactor biosynthesis; adenosylcobalamin biosynthesis; cob(II)yrinate a,c-diamide from sirohydrochlorin (anaerobic route): step 10/10.

Features

Showing features for active site, site.

TypeIDPosition(s)Description
Active site352Nucleophile
Site467Increases nucleophilicity of active site Cys

GO annotations

AspectTerm
Molecular FunctionATP binding
Molecular Functioncobyrinic acid a,c-diamide synthase activity
Biological Processcobalamin biosynthetic process
Biological Processglutamine metabolic process
Biological Processmethanogenesis

Keywords

Enzyme and pathway databases

Names & Taxonomy

Protein names

  • Recommended name
    Cobyrinate a,c-diamide synthase
  • EC number
  • Alternative names
    • Cobyrinic acid a,c-diamide synthetase
    • Ni-sirohydrochlorin a,c-diamide synthase
      (EC:6.3.5.12
      ) . EC:6.3.5.12 (UniProtKB | ENZYME | Rhea)
    • Ni-sirohydrochlorin a,c-diamide synthetase

Gene names

    • Name
      cbiA
    • Synonyms
      cfbB
    • Ordered locus names
      Mbar_A0348

Organism names

Accessions

  • Primary accession
    Q46FL0

PTM/Processing

Features

Showing features for chain.

TypeIDPosition(s)Description
ChainPRO_00004424591-494Cobyrinate a,c-diamide synthase

Proteomic databases

Interaction

Protein-protein interaction databases

Family & Domains

Features

Showing features for domain.

TypeIDPosition(s)Description
Domain270-475GATase cobBQ-type

Domain

Comprises of two domains. The C-terminal domain contains the binding site for glutamine and catalyzes the hydrolysis of this substrate to glutamate and ammonia. The N-terminal domain is anticipated to bind ATP, and cobyrinate or Ni-sirohydrochlorin, and catalyzes the ultimate synthesis of the diamide product. The ammonia produced via the glutaminase domain is probably translocated to the adjacent domain via a molecular tunnel, where it reacts with an activated intermediate.

Sequence similarities

Belongs to the CobB/CbiA family.

Keywords

Phylogenomic databases

Family and domain databases

Sequence

  • Sequence status
    Complete
  • Length
    494
  • Mass (Da)
    53,786
  • Last updated
    2005-09-13 v1
  • Checksum
    88D530FF1A2500C4
MLNDKQSVENIPRILISADRSSSGKTTISMGLMAALVSRGYKVQPFKVALDYIDPSYHTEITGRFCRNLDGYLMDENGILDVYTHACEAGEKADIAIIEGVRGLYEGFESLSDLGSTAQIAKILNCPVIFVINARSITRSSAALINGYRNFDPDVEIAGVILNNIGSRRHAKKAKEAIEYYTGVPVIGIVPRDPAMQISMRHLGLMPALEGRRRLGDGGFEARLRGIEEIINKGIDVDRFMEIAKSAKALKSPENSVFSSVSDPGAPRPKIGVALDEAFNFYYRDNIDLLNLAGAEIVYFSPVKDASLPEVDGLYIGGGYPELFAAELEANESMRQDIKKASAAGMPIYAECGGLMYLTEKISTGVPGKGTYHDASMPESTYSMVGALPGHTIMGQTRVVSYNIGTLNKDCLLGKKYNSFKGHEFHHSEIREIPEDAEFAITLSRGTGIKNGMDGLISGNTLGSYAHLHGVAYREFASSLVEAARNFRDSRVLP

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
CP000099
EMBL· GenBank· DDBJ
AAZ69332.1
EMBL· GenBank· DDBJ
Genomic DNA

Genome annotation databases

Similar Proteins

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