PDBsum entry 2ahk

Oxidoreductase/metal transport

PDB id: 2ahk

Contents

Protein chains

273 a.a. *

72 a.a. *

Ligands

NO3 ×4

Metals

_CU ×3

Waters ×315

* Residue conservation analysis

PDB id:

2ahk

Name:

Oxidoreductase/metal transport

Title:

Crystal structure of the met-form of the copper-bound streptomyces castaneoglobisporus tyrosinase in complex with a caddie protein obtained by soking in cupric sulfate for 6 months

Structure:

Tyrosinase. Chain: a. Engineered: yes. Caddie protein orf378. Chain: b. Synonym: melc. Engineered: yes

Source:

Streptomyces castaneoglobisporus. Organism_taxid: 79261. Gene: tyrc. Expressed in: escherichia coli. Expression_system_taxid: 562. Gene: orf378.

Biol. unit:

Dimer (from PQS)

Resolution:

1.71Å R-factor: 0.194 R-free: 0.241

Authors:

Y.Matoba,T.Kumagai,A.Yamamoto,H.Yoshitsu,M.Sugiyama

Key ref:

Y.Matoba et al. (2006). Crystallographic evidence that the dinuclear copper center of tyrosinase is flexible during catalysis. J Biol Chem, 281, 8981-8990. PubMed id: 16436386 DOI: 10.1074/jbc.M509785200

Date:

28-Jul-05 Release date: 31-Jan-06

Protein chain

Q83WS2  (Q83WS2_9ACTN) -  Tyrosinase from Streptomyces castaneoglobisporus

Seq: 273 a.a.

Struc: 273 a.a.*

Protein chain

Q83WS1  (Q83WS1_9ACTN) -  MelC from Streptomyces castaneoglobisporus

Seq: 126 a.a.

Struc: 72 a.a.

* PDB and UniProt seqs differ at 1 residue position (black cross)

Enzyme reactions

• Enzyme class: Chain A: E.C.1.14.18.1 - tyrosinase.
• Pathway: Melanin Biosynthesis
• Reaction:
  1. L-tyrosine + O2 = L-dopaquinone + H2O
  2. 2 L-dopa + O2 = 2 L-dopaquinone + 2 H2O
• Cofactor: Cu cation

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

reference

DOI no: 10.1074/jbc.M509785200

J Biol Chem 281:8981-8990 (2006)

PubMed id: 16436386

Crystallographic evidence that the dinuclear copper center of tyrosinase is flexible during catalysis.

Y.Matoba, T.Kumagai, A.Yamamoto, H.Yoshitsu, M.Sugiyama.

ABSTRACT

At high resolution, we determined the crystal structures of copper-bound and metal-free tyrosinase in a complex with ORF378 designated as a "caddie" protein because it assists with transportation of two CuII ions into the tyrosinase catalytic center. These structures suggest that the caddie protein covers the hydrophobic molecular surface of tyrosinase and interferes with the binding of a substrate tyrosine to the catalytic site of tyrosinase. The caddie protein, which consists of one six-strandedbeta-sheet and one alpha-helix, has no similarity with all proteins deposited into the Protein Data Bank. Although tyrosinase and catechol oxidase are classified into the type 3 copper protein family, the latter enzyme lacks monooxygenase activity. The difference in catalytic activity is based on the structural observations that a large vacant space is present just above the active center of tyrosinase and that one of the six His ligands for the two copper ions is highly flexible. These structural characteristics of tyrosinase suggest that, in the reaction that catalyzes the ortho-hydroxylation of monophenol, one of the two Cu(II) ions is coordinated by the peroxide-originated oxygen bound to the substrate. Our crystallographic study shows evidence that the tyrosinase active center formed by dinuclear coppers is flexible during catalysis.

Selected figure(s)

Figure 5.
FIGURE 5. Structural similarity. A, stereo representation of the superposition of tyrosinase and structurally homologous proteins, potato catechol oxidase (Protein Data Bank code 1BT1) and octopus hemocyanin (Protein Data Bank code 1JS8). Red, blue, and green indicate the backbone traces of tyrosinase, catechol oxidase, and hemocyanin, respectively. The yellow sphere indicates the two copper ions in the catalytic center. To emphasize similarity, the C-terminal domain of hemocyanin is omitted from the figure. B, stereo view of the superposition of ORF378 and the SH2 domain in the growth factor-bound protein 2 (Protein Data Bank code 1GRI). Red and blue indicate the backbone trace of ORF378 and the SH2 domain in the growth factor-bound protein 2, respectively.

Figure 9.
FIGURE 9. Structure-based catalytic mechanism of tyrosinase. The oxy form of tyrosinase catalyzes the conversion of monophenol to the corresponding quinone through the ortho-diphenol formation. In this scheme, His^54 is released from the Cu^A site, resulting in the formation of the bidentate intermediate. The met and oxy forms of tyrosinase can catalyze the conversion of ortho-diphenol to the corresponding quinone. This reaction should progress similarly to that of catechol oxidase.

The above figures are reprinted by permission from the ASBMB: J Biol Chem (2006, 281, 8981-8990) copyright 2006.

Figures were selected by an automated process.