Lipase/lipooxygenase, PLAT/LH2 (IPR008976)
Short name: Lipase_LipOase
- Lipase/lipooxygenase, PLAT/LH2 (IPR008976)
- PLAT/LH2 domain (IPR001024)
Lipoxygenases (EC:1.13.11.-) are a class of iron-containing dioxygenases which catalyses the hydroperoxidation of lipids, containing a cis,cis-1,4-pentadiene structure. They are common in plants where they may be involved in a number of diverse aspects of plant physiology including growth and development, pest resistance, and senescence or responses to wounding. In mammals a number of lipoxygenases isozymes are involved in the metabolism of prostaglandins and leukotrienes [PMID: 3017195]. Sequence data is available for the following lipoxygenases:
- Plant lipoxygenases (EC:18.104.22.168). Plants express a variety of cytosolic isozymes as well as what seems to be a chloroplast isozyme [PMID: 7508918].
- Mammalian arachidonate 5-lipoxygenase (EC:22.214.171.124).
- Mammalian arachidonate 12-lipoxygenase (EC:126.96.36.199).
- Mammalian erythroid cell-specific 15-lipoxygenase (EC:188.8.131.52).
The iron atom in lipoxygenases is bound by four ligands, three of which are histidine residues [PMID: 8502991]. Six histidines are conserved in all lipoxygenase sequences, five of them are found clustered in a stretch of 40 amino acids. This region contains two of the three iron-ligands; the other histidines have been shown [PMID: 1567851] to be important for the activity of lipoxygenases.
This entry represents a domain found in lipoxygenases and other enzymes. It is known as the PLAT (Polycystin-1, Lipoxygenase, Alpha-Toxin) domain or LH2 (Lipoxygenase homology) domain, is found in a variety of membrane or lipid associated proteins. Structurally, this domain forms a beta-sandwich composed of two sheets of four strands each [PMID: 10469604, PMID: 11985859, PMID: 11412104]. The most highly conserved regions coincide with the beta-strands, with most of the highly conserved residues being buried within the protein. An exception to this is a surface lysine or arginine that occurs on the surface of the fifth beta-strand of the eukaryotic domains. In pancreatic lipase, the lysine in this position forms a salt bridge with the procolipase protein. The conservation of a charged surface residue may indicate the location of a conserved ligand-binding site. It is thought that this domain may mediate membrane attachment via other protein binding partners.
- SSF49723 (SSF49723)