Domain

Lipase/lipooxygenase, PLAT/LH2 (IPR008976)

Short name: Lipase_LipOase

Domain relationships

Description

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:1.13.11.12). Plants express a variety of cytosolic isozymes as well as what seems to be a chloroplast isozyme [PMID: 7508918].
  • Mammalian arachidonate 5-lipoxygenase (EC:1.13.11.34).
  • Mammalian arachidonate 12-lipoxygenase (EC:1.13.11.31).
  • Mammalian erythroid cell-specific 15-lipoxygenase (EC:1.13.11.33).

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.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
SUPERFAMILY