PDBsum entry 4j6t

Oxidoreductase

PDB id: 4j6t

Contents

Protein chains

287 a.a.

Metals

_CU ×4

Waters ×207

PDB id:

4j6t

Name:

Oxidoreductase

Title:

Crystal structure of tyrosinase from bacillus megaterium f197a mutant

Structure:

Tyrosinase. Chain: a, b. Engineered: yes. Mutation: yes

Source:

Bacillus megaterium. Organism_taxid: 1404. Expressed in: escherichia coli. Expression_system_taxid: 469008.

Resolution:

2.43Å R-factor: 0.198 R-free: 0.238

Authors:

M.Kanteev,M.Goldfeder,N.Adir,A.Fishman

Key ref:

M.Kanteev et al. (2013). The mechanism of copper uptake by tyrosinase from Bacillus megaterium. J Biol Inorg Chem, 18, 895-903. PubMed id: 24061559 DOI: 10.1007/s00775-013-1034-0

Date:

12-Feb-13 Release date: 25-Dec-13

Protein chains

B2ZB02  (B2ZB02_PRIMG) -  Tyrosinase from Priestia megaterium

Seq: 297 a.a.

Struc: 287 a.a.*

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

Enzyme reactions

• Enzyme class: 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: 10.1007/s00775-013-1034-0

J Biol Inorg Chem 18:895-903 (2013)

PubMed id: 24061559

The mechanism of copper uptake by tyrosinase from Bacillus megaterium.

M.Kanteev, M.Goldfeder, M.Chojnacki, N.Adir, A.Fishman.

ABSTRACT

Tyrosinase belongs to the type 3 copper enzyme family, containing a dinuclear copper center, CuA and CuB. It is mainly responsible for melanin production in a wide range of organisms. Although copper ions are essential for the activity of tyrosinase, the mechanism of copper uptake is still unclear. We have recently determined the crystal structure of tyrosinase from Bacillus megaterium (TyrBm) and revealed that this enzyme has tighter binding of CuA in comparison with CuB. Investigating copper accumulation in TyrBm, we found that the presence of copper has a more significant effect on the diphenolase activity. By decreasing the concentration of copper, we increased the diphenolase to monophenolase activity ratio twofold. Using a rational design approach, we identified five variants having an impact on copper uptake. We have found that a major role of the highly conserved Asn205 residue is to stabilize the orientation of the His204 imidazole ring in the binding site, thereby promoting the correct coordination of CuB. Further investigation of these variants revealed that Phe197, Met61, and Met184, which are located at the entrance to the binding site, not only play a role in copper uptake, but are also important for enhancing the diphenolase activity. We propose a mechanism of copper accumulation by the enzyme as well as an approach to changing the selectivity of TyrBm towards L-dopa production.