A multifunctional lipoxygenase with fatty acid hydroperoxide cleaving activity from the moss Physcomitrella patens.
A complex mixture of fatty acid-derived aldehydes, ketones, and alcohols is released upon wounding of the moss Physcomitrella patens. To investigate the formation of these oxylipins at the molecular level we isolated a lipoxygenase from P. patens, which was identified in an EST library by sequence homology to lipoxygenases from plants. Sequence analysis of the cDNA showed that it exhibits a domain structure similar to that of type2 lipoxygenases from plants, harboring an N-terminal import signal for chloroplasts. The recombinant protein was identified as arachidonate 12-lipoxygenase and linoleate 13-lipoxygenase with a preference for arachidonic acid and eicosapentaenoic acid. In contrast to any other lipoxygenase cloned so far, this enzyme exhibited in addition an unusual high hydroperoxidase and also a fatty acid chain-cleaving lyase activity. Because of these unique features the pronounced formation of (2Z)-octen-1-ol, 1-octen-3-ol, the dienal (5Z,8Z,10E)-12-oxo-dodecatrienoic acid and 12-keto eicosatetraenoic acid was observed when arachidonic acid was administered as substrate. 12-Hydroperoxy eicosatetraenoic acid was found to be only a minor product. Moreover, the P. patens LOX has a relaxed substrate tolerance accepting C(18)-C(22) fatty acids giving rise to even more LOX-derived products. In contrast to other lipoxygenases a highly diverse product spectrum is formed by a single enzyme accounting for most of the observed oxylipins produced by the moss. This single enzyme might, in a fast and effective way, be involved in the formation of signal and/or defense molecules thus contributing to the broad resistance of mosses against pathogens.
Senger
Toralf
T
Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK), Corrensstr. 3, D-06466 Gatersleben, Germany.
Wichard
Thomas
T
Kunze
Susan
S
Göbel
Cornelia
C
Lerchl
Jens
J
Pohnert
Georg
G
Feussner
Ivo
I
D000595:Amino Acid Sequence; D001092:Arachidonate 12-Lipoxygenase / Q000737:chemistry; D019068:Bryopsida / Q000737:chemistry* / Q000201:enzymology*; D020134:Catalytic Domain; D002736:Chloroplasts / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000378:metabolism; D015118:Eicosapentaenoic Acid / Q000737:chemistry; D020224:Expressed Sequence Tags; D005227:Fatty Acids / Q000378:metabolism*; D008401:Gas Chromatography-Mass Spectrometry; D015723:Gene Library; D017343:Genes, Plant; D006861:Hydrogen Peroxide / Q000737:chemistry*; D007651:Keto Acids / Q000737:chemistry; D008084:Lipoxygenase / Q000737:chemistry / Q000502:physiology*; D008190:Lyases / Q000737:chemistry; D008956:Models, Chemical; D008969:Molecular Sequence Data; D010802:Phylogeny; D010940:Plant Proteins / Q000737:chemistry; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D013997:Time Factors; D014466:Ultraviolet Rays
D018076:DNA, Complementary; D005227:Fatty Acids; D007651:Keto Acids; D010940:Plant Proteins; D015118:Eicosapentaenoic Acid; D006861:Hydrogen Peroxide; D008084:Lipoxygenase; D001092:Arachidonate 12-Lipoxygenase; D008190:Lyases