title: A high affinity serotonin- and histamine-binding lipocalin from tick saliva.
abstract: To overcome the inflammatory response in its host, the cattle-feeding, brown ear tick secretes histamine-binding proteins into the feeding site. These proteins are beta-barrels with two internal binding sites: a high-affinity (H) site for histamine and a site (L) for which the natural ligand is unknown. Here we report a related protein (SHBP), secreted by a rodent- and cattle-feeding tick, that traps both histamine and serotonin. The histamine-binding H site is well conserved in SHBP, whereas residue changes in the L-like site are consistent with binding of the bulkier serotonin molecule. As histamine is a key inflammatory mediator in cattle, while serotonin takes on this role in rodents, the diversification of these tick proteins may reflect host adaptation.
authors.affiliation: CEH Oxford, Mansfield Road, Oxford, OX1 3SR, UK.
authors.forename: S
authors.initials: S
authors.lastname: Sangamnatdej
authors.forename: G C
authors.initials: GC
authors.lastname: Paesen
authors.forename: M
authors.initials: M
authors.lastname: Slovak
authors.forename: P A
authors.initials: PA
authors.lastname: Nuttall
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D018076:DNA, Complementary; D003870:Dermacentor / Q000235:genetics / Q000378:metabolism*; D005260:Female; D006632:Histamine / Q000378:metabolism*; D008297:Male; D008969:Molecular Sequence Data; D012701:Serotonin / Q000378:metabolism*; D018411:Spodoptera
chemical_list: D002352:Carrier Proteins; D018076:DNA, Complementary; D012701:Serotonin; D006632:Histamine