PDBsum entry: 1mae

Oxidoreductase(chnh2(d)-deaminating)

PDB id: 1mae

Contents

Protein chains

124 a.a. *

373 a.a.* *

Ligands

HDZ

Waters ×85

* Residue conservation analysis

* C-alpha coords only

PDB id:

1mae

Name:

Oxidoreductase(chnh2(d)-deaminating)

Title:

The active site structure of methylamine dehydrogenase: hydrazines identify c6 as the reactive site of the tryptophan derived quinone cofactor

Structure:

Methylamine dehydrogenase (light subunit). Chain: l. Engineered: yes. Methylamine dehydrogenase (heavy subunit). Chain: h. Engineered: yes

Source:

Paracoccus versutus. Organism_taxid: 34007. Organism_taxid: 34007

Biol. unit:

Tetramer (from PQS)

Resolution:

2.80Å R-factor: 0.183

Authors:

E.G.Huizinga,F.M.D.Vellieux,W.G.J.Hol

Key ref:

E.G.Huizinga et al. (1992). Active site structure of methylamine dehydrogenase: hydrazines identify C6 as the reactive site of the tryptophan-derived quinone cofactor. Biochemistry, 31, 9789-9795. PubMed id: 1390754 DOI: 10.1021/bi00155a036

Date:

20-May-92 Release date: 31-Jan-94

Protein chain

P22641  (DHML_PARVE) -  Methylamine dehydrogenase light chain

Seq: 188 a.a.

Struc: 124 a.a.*

Protein chain

P23006  (DHMH_PARVE) -  Methylamine dehydrogenase heavy chain

Seq: 426 a.a.

Struc: 373 a.a.*

* PDB and UniProt seqs differ at 171 residue positions (black crosses)

Enzyme reactions

• Enzyme class: Chains L, H: E.C.1.4.9.1 - Methylamine dehydrogenase (amicyanin).
• Reaction: Methylamine + H₂O + amicyanin = formaldehyde + ammonia + reduced amicyanin
• Cofactor: Tryptophan tryptophylquinone

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

 Gene Ontology (GO) functional annotation 

• Cellular component: periplasmic space (2 terms)
• Biological process: oxidation-reduction process (5 terms)
• Biochemical function: protein binding (4 terms)

Added reference

DOI no: 10.1021/bi00155a036

Biochemistry 31:9789-9795 (1992)

PubMed id: 1390754

Active site structure of methylamine dehydrogenase: hydrazines identify C6 as the reactive site of the tryptophan-derived quinone cofactor.

E.G.Huizinga, B.A.van Zanten, J.A.Duine, J.A.Jongejan, F.Huitema, K.S.Wilson, W.G.Hol.

ABSTRACT

To identify the reactive part of the orthoquinone function of the tryptophan-derived cofactor found in methylamine dehydrogenase (MADH), we have determined the crystal structures of MADH from Thiobacillus versutus inhibited by methylhydrazine and (2,2,2-trifluoroethyl)hydrazine. Extra electron density attached to C6 of the tryptophyl tryptophanquinone cofactor shows that this atom and not C7 is the reactive part of the ortho-quinone moiety. The density retained after hydrazine inhibition is much less extensive than expected, however, suggesting that partial breakdown of the inhibitors after reaction with the cofactor may take place. A detailed description is presented of the cofactor environment in an improved model of MADH which now includes information from the recently determined gene sequence of the cofactor-containing subunit [Ubbink, M., van Kleef, M.A.G., Kleinjan, D., Hoitink, C.W.G., Huitema, F., Beintema, J.J., Duine, J.A., & Canters, G.W. (1991) Eur. J. Biochem. 202, 1003-1012]. We hypothesize that Asp76 is responsible for proton abstraction from the alpha-carbon of the substrate during catalysis.