Sandbox Reserved 1097: Difference between revisions
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* '''The cystein-rich subdomain''' ''(25-126)'' | * '''The cystein-rich subdomain''' ''(25-126)'' | ||
The cystein-rich domain has an epidermal growth factor‐like fold formed by two pairs of short antiparallel | The cystein-rich domain has an epidermal growth factor‐like fold formed by two pairs of short antiparallel β-strands (62-66/98-102 and 116-118/124-126)<ref name= "lai"/> . This previous domain strongly interacts with the tyrosinase-like subdomain by the lastloop of the cystein-rich domain preceding the N-terminal domain. The role of the cystein-rich domain is still unknown, it is only found in [https://en.wikipedia.org/wiki/Mammal mammalians]. This domain is stabilized by three (42-65/56-99/101-110) disulfide bounds and is located at the opposite of the active site. It is said that the cystein-rich domain might help the formation of a complex between TYR and TYRP2.<ref name="Xlai"/><ref name= "lai"/> | ||
* '''The tyrosinase-like subdomain''' ''(127-477)'' | * '''The tyrosinase-like subdomain''' ''(127-477)'' | ||
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==== Differences ==== | ==== Differences ==== | ||
The main difference between these three enzymes is the nature of metal ions they bind on the active site. TYRP1 and TYRP2 bind two zinc ions whereas TYR binds two copper ions. Therefore these enzymes catalyze different reactions: TYR catalyzes the conversion of tyrosine into L-DOPA and then in Dopaquinone,TYRP2 isomerizes dopachrome to DHICA. Moreover, the active site of TYRP2 contains two molecules of water and a substrate interacting with both Zn2+ during reactions, whereas TYRP1 active site contains only one molecule of water and a substrate which are interacting with only one Zn2+ ion. However, no 3D-structure of TYRP2 is currently available so the exact coordination of metal ions in the active site stays unclear.<ref name="Xlai"/> | The main difference between these three enzymes is the nature of metal ions they bind on the active site. TYRP1 and TYRP2 bind two zinc ions whereas TYR binds two copper ions. Therefore these enzymes catalyze different reactions: TYR catalyzes the conversion of tyrosine into L-DOPA and then in Dopaquinone,TYRP2 isomerizes dopachrome to DHICA. Moreover, the active site of TYRP2 contains two molecules of water and a substrate interacting with both Zn2+ during reactions, whereas TYRP1 active site contains only one molecule of water and a substrate which are interacting with only one Zn2+ ion(ZnA). However, no 3D-structure of TYRP2 is currently available so the exact coordination of metal ions in the active site stays unclear.<ref name="Xlai"/> | ||
Besides, TYRP1 has the longuest sequence of the three proteins (TYR : 529, TYRP2 : 519, TYRP1 : 537) and contrary to TYRP1 and TYRP2, TYR contains six sites of N-glycosylation.<ref name="Xlai"/> | Besides, TYRP1 has the longuest sequence of the three proteins (TYR : 529, TYRP2 : 519, TYRP1 : 537) and contrary to TYRP1 and TYRP2, TYR contains six sites of N-glycosylation.<ref name="Xlai"/> | ||
