PDBsum entry 1mg2

Oxidoreductase

PDB id: 1mg2

Contents

Protein chains

382 a.a. *

125 a.a. *

105 a.a. *

147 a.a. *

Ligands

PO4 ×8

HEC ×4

Metals

_CU ×4

_NA ×4

Waters ×1685

* Residue conservation analysis

PDB id:

1mg2

Name:

Oxidoreductase

Title:

Mutation of alpha phe55 of methylamine dehydrogenase alters the reorganization energy and electronic coupling for its electron transfer reaction with amicyanin

Structure:

Methylamine dehydrogenase, heavy chain. Chain: a, e, i, m. Synonym: madh. Engineered: yes. Mutation: yes. Methylamine dehydrogenase, light chain. Chain: b, f, j, n. Synonym: madh. Engineered: yes.

Source:

Paracoccus denitrificans. Organism_taxid: 266. Expressed in: rhodobacter sphaeroides. Expression_system_taxid: 1063. Expression_system_taxid: 1063

Biol. unit:

Octamer (from PQS)

Resolution:

2.25Å R-factor: 0.173 R-free: 0.210

Authors:

D.Sun,Z.W.Chen,F.S.Mathews,V.L.Davidson

Key ref:

D.Sun et al. (2002). Mutation of alphaPhe55 of methylamine dehydrogenase alters the reorganization energy and electronic coupling for its electron transfer reaction with amicyanin. Biochemistry, 41, 13926-13933. PubMed id: 12437349 DOI: 10.1021/bi026654x

Date:

14-Aug-02 Release date: 11-Dec-02

Protein chains

P29894  (DHMH_PARDE) -  Methylamine dehydrogenase heavy chain from Paracoccus denitrificans

Seq: 417 a.a.

Struc: 382 a.a.*

Protein chains

P22619  (DHML_PARDE) -  Methylamine dehydrogenase light chain from Paracoccus denitrificans

Seq: 188 a.a.

Struc: 125 a.a.*

Protein chains

P22364  (AMCY_PARDE) -  Amicyanin from Paracoccus denitrificans

Seq: 131 a.a.

Struc: 105 a.a.

Protein chains

P29899  (CYCL_PARDE) -  Cytochrome c-L from Paracoccus denitrificans

Seq: 177 a.a.

Struc: 147 a.a.

* PDB and UniProt seqs differ at 4 residue positions (black crosses)

Enzyme reactions

• Enzyme class: Chains A, B, E, F, I, J, M, N: E.C.1.4.9.1 - methylamine dehydrogenase (amicyanin).
• Reaction: 2 oxidized [amicyanin] + methylamine + H2O = 2 reduced [amicyanin] + formaldehyde + NH4⁺ + 2 H⁺
• Cofactor: Tryptophan tryptophylquinone

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

Added reference

DOI no: 10.1021/bi026654x

Biochemistry 41:13926-13933 (2002)

PubMed id: 12437349

Mutation of alphaPhe55 of methylamine dehydrogenase alters the reorganization energy and electronic coupling for its electron transfer reaction with amicyanin.

D.Sun, Z.W.Chen, F.S.Mathews, V.L.Davidson.

ABSTRACT

Methylamine dehydrogenase (MADH) possesses an alpha(2)beta(2) structure with each smaller beta subunit possessing a tryptophan tryptophylquinone (TTQ) prosthetic group. Phe55 of the alpha subunit is located where the substrate channel from the enzyme surface opens into the active site. Site-directed mutagenesis of alphaPhe55 has revealed roles for this residue in determining substrate specificity and binding monovalent cations at the active site. It is now shown that the alphaF55A mutation also increases the rate of the true electron transfer (ET) reaction from O-quinol MADH to amicyanin. The reorganization energy associated with the ET reaction is decreased from 2.3 to 1.8 eV. The electronic coupling associated with the ET reaction is decreased from 12 to 3 cm(-1). The crystal structure of alphaF55A MADH in complex with its electron acceptors, amicyanin and cytochrome c-551i, has been determined. Little difference in the overall structure is seen, relative to the native complex; however, there are significant changes in the solvent content of the active site and substrate channel. The crystal structure of alphaF55A MADH has also been determined with phenylhydrazine covalently bound to TTQ in the active site. Phenylhydrazine binding significantly perturbs the orientation of the TTQ rings relative to each other. The ET results are discussed in the context of the new and old crystal structures of the native and mutant enzymes.