Cloned (Comment) | Organism |
---|---|
recombinant expression of His-tagged enzyme in Escherichia coli BL21 | Priestia megaterium |
Crystallization (Comment) | Organism |
---|---|
purified enzyme bound with L-tyrosine or L-dopa and zinc ions, hanging drop vapour diffusion method, mixing of 0.002 ml or 2 mg/ml protein in 20mM Tris-HCl, pH 7.5, and 500 mM NaCl, with 0.002 ml reservoir solution containing 18% PEG 8000 and 0.1 M cacodylic acid, pH 6.5, and equilibration against 0.6 ml of reservoir solution, 20°C, soaking of the crystals in inhibiting ZnCl2 before soaking them in the substrate solution in order to trap the substrates within the active site of TyrBm in the crystal, X-ray diffraction structure determination and analysis at 2.2-2.5 A resolution | Priestia megaterium |
Inhibitors | Comment | Organism | Structure |
---|---|---|---|
Zn2+ | binding structure in the active site, modeling, overview. Replacing the Cu2+ with Zn2+ ions can be performed in TyrBm without structural consequences, while the presence of Zn2+ ions inhibits the activity of tyrosinase on both monophenols and diphenols | Priestia megaterium |
Metals/Ions | Comment | Organism | Structure |
---|---|---|---|
Cu2+ | the enzyme is a type-3 copper protein | Priestia megaterium |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
2 L-dopa + O2 | Priestia megaterium | - |
2 dopaquinone + 2 H2O | - |
? | |
tyrosine + O2 | Priestia megaterium | - |
dopaquinone + H2O | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Priestia megaterium | - |
- |
- |
Purification (Comment) | Organism |
---|---|
recombinant His-tagged enzyme from Escherichia coli BL21 by nickel affinity chromatography | Priestia megaterium |
Reaction | Comment | Organism | Reaction ID |
---|---|---|---|
L-tyrosine + O2 = dopaquinone + H2O | molecular reaction mechanism and substrate binding mode, L-tyrosine in the active site forms hydrogen bonds with R209 via its carboxyl side chain | Priestia megaterium |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
2 L-dopa + O2 | - |
Priestia megaterium | 2 dopaquinone + 2 H2O | - |
? | |
tyrosine + O2 | - |
Priestia megaterium | dopaquinone + H2O | - |
? |
Synonyms | Comment | Organism |
---|---|---|
TyrBm | - |
Priestia megaterium |
General Information | Comment | Organism |
---|---|---|
metabolism | tyrosinase is responsible for the two initial enzymatic steps in the conversion of tyrosine to melanin | Priestia megaterium |
additional information | determination of tyrosinase substrate-binding modes, overview. Both monophenol hydroxylation and diphenol oxidation occur at the same site. Compared to tyrosinase, the concurrent presence of a phenylalanine above the active site and a restricting thioether bond on the histidine coordinating copper ion CuA prevent hydroxylation of monophenols by catechol oxidases, EC 1.10.3.1. A conserved water molecule activated by E195 and N205 is proposed to mediate deprotonation of the monophenol at the active site. The diphenol L-dopa binds to uinc ion ZnA in the active site in the same orientation as tyrosine, assisted by interactions with H208, both the hydroxylation and oxidation activities occur without significant binding site reorganization. Comarison of binding modes of catecol oxidase/diphenolase, and tyrosinase/monophenolase. Structure-supported monophenol hydroxylation and deprotonation mechanism, overview | Priestia megaterium |