Sandbox Reserved 1097: Difference between revisions
From Proteopedia
Jump to navigationJump to search
Faure Marina (talk | contribs) No edit summary |
Faure Marina (talk | contribs) No edit summary |
||
| Line 32: | Line 32: | ||
The active site is located in the tyrosinase-like subdomain. It is delimited by four helices and contains the binuclear metal-binding site. It looks like type-3 binuclear copper-binding site of Tyrosinases. The two ions are bound with planar trigonal geometry and the distance between them is : 3,5 ± 0,1 Ā. A molecule of water located at the same distance (2,1 ± 0,1 Ā) from the two ions can make a bridge between them. mutations on amino acids of the active site have no significant affect on TYRP1 activity. | The active site is located in the tyrosinase-like subdomain. It is delimited by four helices and contains the binuclear metal-binding site. It looks like type-3 binuclear copper-binding site of Tyrosinases. The two ions are bound with planar trigonal geometry and the distance between them is : 3,5 ± 0,1 Ā. A molecule of water located at the same distance (2,1 ± 0,1 Ā) from the two ions can make a bridge between them. mutations on amino acids of the active site have no significant affect on TYRP1 activity. | ||
The crystal structure of TYRP1 shows that TYRP1 can bind tyrosine, mimosine (DOPA equivalent), kojic acid, tropolone. | The crystal structure of TYRP1 shows that TYRP1 can bind tyrosine, mimosine (DOPA equivalent), kojic acid, tropolone. DOPA and tyrosine can interact with the active site by their aromatic hydroxy or keto groups through hydrogen bounds with water molecule between the ions. Aromatic stacking interactions with H381 and hydrogen bonds between carboxylate group, ARG374 and Ser 394 represent other interactions between these substrates and the active site. Tropolone have direct interactions with one of the Zn2+ ion because of its metal-chelating property. The interactions between tropolone and Zn2+ show that the binuclear site is flexible. The ring hydroxy and keto groups of kojic acid bind the Zinc ion away from 3Ā. All these non specific interactions may confirm that TYRP1 can have several roles. | ||
(image à faire) | (image à faire) | ||
| Line 48: | Line 48: | ||
(image à faire) | (image à faire) | ||
According to crystal knowledges, it is said that TYRP1 and TYR can bind the same | According to crystal knowledges, it is said that TYRP1 and TYR can bind the same substrates and even if the composition of the active site is different, it doesn't affect the binding modes of these compounds. | ||
The three enzymes have several sites of N-glycosylation which are important for their maturation, two of these sites are shared by the three enzymes. TYRP1 and 2 have both six sites and among them, four are exactly the same. <ref name="Xlai"/> | The three enzymes have several sites of N-glycosylation which are important for their maturation, two of these sites are shared by the three enzymes. TYRP1 and 2 have both six sites and among them, four are exactly the same. <ref name="Xlai"/> | ||
