title: Salicyl alcohol oxidase of the chemical defense secretion of two chrysomelid leaf beetles. Molecular and functional characterization of two new members of the glucose-methanol-choline oxidoreductase gene family.
abstract: Salicyl alcohol oxidase is an extracellular enzyme that occurs in glandular reservoirs of chrysomelid leaf beetle larvae and catalyzes the formation of salicylaldehyde, a volatile deterrent used by the larvae against predators. Salicyl alcohol is the hydrolysis product of salicin, a plant-derived precursor taken up by the beetle larvae from the leaves of willow and poplar trees. The cDNA encoding salicyl alcohol oxidase from two related species Chrysomela tremulae and Chrysomela populi has been identified, cloned, and expressed in an active form in Escherichia coli. The open reading frame of 623 amino acids begins in both enzymes with an N-terminal signal peptide of 21 amino acids. Sequence comparison has revealed that salicyl alcohol oxidase belongs to the family of glucose-methanol-choline oxidoreductase-like sequences with mostly unknown function. Enzymes of this family share similar overall structure with an essentially identical FAD-binding site but possess different catalytic activities. The data suggest that salicyl alcohol oxidase, essential for the activation of the plant-derived precursor salicin, was originally recruited from an oxidase involved in the autogenous biosynthesis of iridoid monoterpenes and found in related chrysomelid leaf beetle species.
authors.affiliation: Botanisches Institut und Botanischer Garten, Universität Kiel, Olshausenstrasse 40, 24098 Kiel, Germany.
authors.forename: Carmen
authors.initials: C
authors.lastname: Michalski
authors.forename: Hoda
authors.initials: H
authors.lastname: Mohagheghi
authors.forename: Manfred
authors.initials: M
authors.lastname: Nimtz
authors.forename: Jacques
authors.initials: J
authors.lastname: Pasteels
authors.forename: Dietrich
authors.initials: D
authors.lastname: Ober
mesh_terms: D000429:Alcohol Oxidoreductases / Q000235:genetics* / Q000378:metabolism; D000447:Aldehydes / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001592:Benzyl Alcohols / Q000378:metabolism; D001665:Binding Sites / Q000502:physiology; D003001:Cloning, Molecular; D001517:Coleoptera / Q000201:enzymology / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics; D005182:Flavin-Adenine Dinucleotide / Q000378:metabolism; D005960:Glucosides; D019476:Insect Proteins / Q000235:genetics* / Q000378:metabolism; D007814:Larva / Q000201:enzymology / Q000235:genetics; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000502:physiology; D032107:Populus; D021382:Protein Sorting Signals / Q000502:physiology; D032108:Salix; D020539:Sequence Analysis, Protein; D017386:Sequence Homology, Amino Acid
chemical_list: D000447:Aldehydes; D001592:Benzyl Alcohols; D005960:Glucosides; D019476:Insect Proteins; D021382:Protein Sorting Signals; D005182:Flavin-Adenine Dinucleotide; C013243:salicylaldehyde; C005696:salicin; D000429:Alcohol Oxidoreductases; C473419:salicyl alcohol oxidase; C010631:salicyl alcohol