title: Possible role of phosphatidylserine-hemocyanin interaction in the innate immune response of Limulus polyphemus.
abstract: Phenoloxidase enzymes and the associated pro-phenoloxidase activation cascade play an essential role in the immune response of arthropods. Phenoloxidase activity can be elicited in the oxygen carrier, hemocyanin, by the addition of the artificial inducer, SDS. There is some evidence to support hemocyanin acting as a phenoloxidase in vivo; however, the identity of natural activators remains unclear. This study explores the role of the phospholipid, phosphatidylserine, as a possible natural activator of hemocyanin-derived phenoloxidase activity. Characterisation of the structural changes associated with activation of hemocyanin-derived phenoloxidase suggests that phosphatidylserine induces similar conformational changes to those caused by the artificial inducer, SDS. We propose that anionic phospholipids, in particular phosphatidylserine, may act as natural activators of hemocyanin-derived phenoloxidase.
authors.affiliation: School of Biological and Environmental Sciences, University of Stirling, Stirling FK9 4LA, Scotland, UK.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Coates
authors.forename: Sharon M
authors.initials: SM
authors.lastname: Kelly
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Nairn
mesh_terms: D000818:Animals; D004156:Catechol Oxidase / Q000378:metabolism; D004792:Enzyme Precursors / Q000378:metabolism; D006433:Hemocyanins / Q000737:chemistry / Q000378:metabolism*; D006737:Horseshoe Crabs / Q000276:immunology* / Q000378:metabolism*; D007113:Immunity, Innate; D014442:Monophenol Monooxygenase / Q000378:metabolism*; D010718:Phosphatidylserines / Q000737:chemistry / Q000378:metabolism*; D010743:Phospholipids / Q000378:metabolism; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology; D013050:Spectrometry, Fluorescence
chemical_list: D004792:Enzyme Precursors; D010718:Phosphatidylserines; D010743:Phospholipids; D012967:Sodium Dodecyl Sulfate; D006433:Hemocyanins; C038451:pro-phenoloxidase; D004156:Catechol Oxidase; D014442:Monophenol Monooxygenase