The origin of 15R-prostaglandins in the Caribbean coral Plexaura homomalla: Molecular cloning and expression of a novel cyclooxygenase
The highest concentrations of prostaglandins in nature are found in the Caribbean gorgonian Plexaura homomalla. Depending on its geographical location, this coral contains prostaglandins with typical mammalian stereochemistry (15S-hydroxy) or the unusual 15R-prostaglandins. Their metabolic origin ha...
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ftpubmed:oai:pubmedcentral.nih.gov:35405 2023-05-15T15:10:39+02:00 The origin of 15R-prostaglandins in the Caribbean coral Plexaura homomalla: Molecular cloning and expression of a novel cyclooxygenase Valmsen, Karin Järving, Ivar Boeglin, William E. Varvas, Külliki Koljak, Reet Pehk, Tõnis Brash, Alan R. Samel, Nigulas 2001-07-03 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC35405 http://www.ncbi.nlm.nih.gov/pubmed/11427702 https://doi.org/10.1073/pnas.131022398 en eng The National Academy of Sciences http://www.ncbi.nlm.nih.gov/pmc/articles/PMC35405 http://www.ncbi.nlm.nih.gov/pubmed/11427702 http://dx.doi.org/10.1073/pnas.131022398 Copyright © 2001, The National Academy of Sciences Biological Sciences Text 2001 ftpubmed https://doi.org/10.1073/pnas.131022398 2013-08-29T07:38:32Z The highest concentrations of prostaglandins in nature are found in the Caribbean gorgonian Plexaura homomalla. Depending on its geographical location, this coral contains prostaglandins with typical mammalian stereochemistry (15S-hydroxy) or the unusual 15R-prostaglandins. Their metabolic origin has remained the subject of mechanistic speculations for three decades. Here, we report the structure of a type of cyclooxygenase (COX) that catalyzes transformation of arachidonic acid into 15R-prostaglandins. Using a homology-based reverse transcriptase–PCR strategy, we cloned a cDNA corresponding to a COX protein from the R variety of P. homomalla. The deduced peptide sequence shows 80% identity with the 15S-specific coral COX from the Arctic soft coral Gersemia fruticosa and ≈50% identity to mammalian COX-1 and COX-2. The predicted tertiary structure shows high homology with mammalian COX isozymes having all of the characteristic structural units and the amino acid residues important in catalysis. Some structural differences are apparent around the peroxidase active site, in the membrane-binding domain, and in the pattern of glycosylation. When expressed in Sf9 cells, the P. homomalla enzyme forms a 15R-prostaglandin endoperoxide together with 11R-hydroxyeicosatetraenoic acid and 15R-hydroxyeicosatetraenoic acid as by-products. The endoperoxide gives rise to 15R-prostaglandins and 12R-hydroxyheptadecatrienoic acid, identified by comparison to authentic standards. Evaluation of the structural differences of this 15R-COX isozyme should provide new insights into the substrate binding and stereospecificity of the dioxygenation reaction of arachidonic acid in the cyclooxygenase active site. Text Arctic PubMed Central (PMC) Arctic Proceedings of the National Academy of Sciences 98 14 7700 7705 |
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Biological Sciences Valmsen, Karin Järving, Ivar Boeglin, William E. Varvas, Külliki Koljak, Reet Pehk, Tõnis Brash, Alan R. Samel, Nigulas The origin of 15R-prostaglandins in the Caribbean coral Plexaura homomalla: Molecular cloning and expression of a novel cyclooxygenase |
topic_facet |
Biological Sciences |
description |
The highest concentrations of prostaglandins in nature are found in the Caribbean gorgonian Plexaura homomalla. Depending on its geographical location, this coral contains prostaglandins with typical mammalian stereochemistry (15S-hydroxy) or the unusual 15R-prostaglandins. Their metabolic origin has remained the subject of mechanistic speculations for three decades. Here, we report the structure of a type of cyclooxygenase (COX) that catalyzes transformation of arachidonic acid into 15R-prostaglandins. Using a homology-based reverse transcriptase–PCR strategy, we cloned a cDNA corresponding to a COX protein from the R variety of P. homomalla. The deduced peptide sequence shows 80% identity with the 15S-specific coral COX from the Arctic soft coral Gersemia fruticosa and ≈50% identity to mammalian COX-1 and COX-2. The predicted tertiary structure shows high homology with mammalian COX isozymes having all of the characteristic structural units and the amino acid residues important in catalysis. Some structural differences are apparent around the peroxidase active site, in the membrane-binding domain, and in the pattern of glycosylation. When expressed in Sf9 cells, the P. homomalla enzyme forms a 15R-prostaglandin endoperoxide together with 11R-hydroxyeicosatetraenoic acid and 15R-hydroxyeicosatetraenoic acid as by-products. The endoperoxide gives rise to 15R-prostaglandins and 12R-hydroxyheptadecatrienoic acid, identified by comparison to authentic standards. Evaluation of the structural differences of this 15R-COX isozyme should provide new insights into the substrate binding and stereospecificity of the dioxygenation reaction of arachidonic acid in the cyclooxygenase active site. |
format |
Text |
author |
Valmsen, Karin Järving, Ivar Boeglin, William E. Varvas, Külliki Koljak, Reet Pehk, Tõnis Brash, Alan R. Samel, Nigulas |
author_facet |
Valmsen, Karin Järving, Ivar Boeglin, William E. Varvas, Külliki Koljak, Reet Pehk, Tõnis Brash, Alan R. Samel, Nigulas |
author_sort |
Valmsen, Karin |
title |
The origin of 15R-prostaglandins in the Caribbean coral Plexaura homomalla: Molecular cloning and expression of a novel cyclooxygenase |
title_short |
The origin of 15R-prostaglandins in the Caribbean coral Plexaura homomalla: Molecular cloning and expression of a novel cyclooxygenase |
title_full |
The origin of 15R-prostaglandins in the Caribbean coral Plexaura homomalla: Molecular cloning and expression of a novel cyclooxygenase |
title_fullStr |
The origin of 15R-prostaglandins in the Caribbean coral Plexaura homomalla: Molecular cloning and expression of a novel cyclooxygenase |
title_full_unstemmed |
The origin of 15R-prostaglandins in the Caribbean coral Plexaura homomalla: Molecular cloning and expression of a novel cyclooxygenase |
title_sort |
origin of 15r-prostaglandins in the caribbean coral plexaura homomalla: molecular cloning and expression of a novel cyclooxygenase |
publisher |
The National Academy of Sciences |
publishDate |
2001 |
url |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC35405 http://www.ncbi.nlm.nih.gov/pubmed/11427702 https://doi.org/10.1073/pnas.131022398 |
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Arctic |
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Arctic |
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Arctic |
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Arctic |
op_relation |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC35405 http://www.ncbi.nlm.nih.gov/pubmed/11427702 http://dx.doi.org/10.1073/pnas.131022398 |
op_rights |
Copyright © 2001, The National Academy of Sciences |
op_doi |
https://doi.org/10.1073/pnas.131022398 |
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Proceedings of the National Academy of Sciences |
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98 |
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14 |
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7700 |
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7705 |
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1766341636388814848 |