Skip to main content

Table 1 Structural differences in the active site of type-3 copper proteins

From: Origin, evolution and classification of type-3 copper proteins: lineage-specific gene expansions and losses across the Metazoa

 

Place-holder residue1

Cysteine-histidine bound2

Disulfide bridges3

α-subclass protein

   

Eubacteria tyrosinases

V

No

No

Archaebacteria tyrosinases

V

No

No

Plantae catechol oxidases

F/L

Yes

2 bridges

Chromalveolata tyrosinases

V

No

No

Amoebozoan tyrosinases

V

No

No

Fungal tyrosinases

V/L/I

Yes

No

Cnidarian tyrosinases

V

No

No

Molluscan hemocyanins

L

Yes

2 bridges

Molluscan tyrosinases

V/I

No

No

Nematode tyrosinases

I

No

No

Urochordate hemocyanins

L

Yes

2 bridges

β-subclass protein

   

Amoebozoan tyrosinases

F

No

No

Fungal tyrosinases

F

No

No

Poriferan tyrosinase

F

No

1 bridge

Arthropod tyrosinases

F

No

2 bridges

Arthropod hemocyanins

F

No

2 bridges

Hemichordate hemocyanin

F

No

No

Urochordate tyrosinases

F

No

No

γ-subclass protein

   

Poriferan tyrosinase

V

No

No

Platyhelminth tyrosinases

V

No

No

Annelid tyrosinases

V

No

No

Hemichordate tyrosinases

V

No

No

Cephalochordate tyrosinases

V

No

No

Urochordate tyrosinases

V

No

No

Vertebrate tyrosinases

V

No

No

  1. 1The placeholder residue blocks the access of the substrate to the active site, affecting the enzymatic activity of type-3 copper proteins.
  2. 2Cysteine-histidine bond is proposed to be involved in the electron transfer process; however, its function is still contentious.
  3. 3Disulfide bridges stabilise protein folding.