Kringle domain
Kringle domains are autonomous protein domains that fold into large loops stabilized by 3 disulfide linkages. These are important in protein–protein interactions with blood coagulation factors. Their name refers to the Kringle, a Scandinavian pastry which they somewhat resemble.
Fragment of bovine prothrombin in complex with calcium and lysophosphatidylserine. The protein associate with membrane through its alpha-helical GLA domain. The adjacent kringle domain is beta-structural (yellow). | |||||||||
| Identifiers | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Symbol | Kringle | ||||||||
| Pfam | PF00051 | ||||||||
| InterPro | IPR000001 | ||||||||
| SMART | KR | ||||||||
| PROSITE | PDOC00020 | ||||||||
| SCOP2 | 1pk4 / SCOPe / SUPFAM | ||||||||
| OPM superfamily | 115 | ||||||||
| OPM protein | 1h8p | ||||||||
| CDD | cd00108 | ||||||||
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Kringle domains have been found in plasminogen, hepatocyte growth factors, prothrombin, and apolipoprotein(a).
Kringles are found throughout the blood clotting and fibrinolytic proteins. Kringle domains are believed to play a role in binding mediators (e.g., membranes, other proteins or phospholipids), and in the regulation of proteolytic activity. Kringle domains are characterised by a triple loop, 3-disulfide bridge structure, whose conformation is defined by a number of hydrogen bonds and small pieces of anti-parallel beta-sheet. They are found in a varying number of copies in some plasma proteins including prothrombin and urokinase-type plasminogen activator, which are serine proteases belonging to MEROPS peptidase family S1A.