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Characterization and comparison of fatty acyl Delta6 desaturase cDNAs from freshwater and marine teleost fish species.

Abstract

Fish are the most important dietary source of the n-3 highly unsaturated fatty acids (HUFA), eicosapentaenoic (EPA) and docosahexaenoic acid (DHA), that have particularly important roles in human nutrition reflecting their roles in critical physiological processes. The objective of the study described here was to clone, functionally characterize and compare expressed fatty acid desaturase genes involved in the production of EPA and DHA in freshwater and marine teleost fish species. Putative fatty acid desaturase cDNAs were isolated and cloned from common carp (Cyprinus carpio) and turbot (Psetta maximus). The enzymic activities of the products of these cDNAs, together with those of cDNAs previously cloned from rainbow trout (Oncorhynchus mykiss) and gilthead sea bream (Sparus aurata), were determined by heterologous expression in the yeast Saccharomyces cerevisiae. The carp and turbot desaturase cDNAs included open reading frames (ORFs) of 1335 and 1338 base pairs, respectively, specifying proteins of 444 and 445 amino acids. The protein sequences possessed all the characteristic features of microsomal fatty acid desaturases, including three histidine boxes, two transmembrane regions, and N-terminal cytochrome b(5) domains containing the haem-binding motif, HPGG. Functional expression showed all four fish cDNAs encode basically unifunctional Delta6 fatty acid desaturase enzymes responsible for the first and rate-limiting step in the biosynthesis of HUFA from 18:3n-3 and 18:2n-6. All the fish desaturases were more active towards the n-3 substrate with 59.5%, 31.5%, 23.1% and 7.0% of 18:3n-3 being converted to 18:4n-3 in the case of turbot, trout, sea bream and carp, respectively. The enzymes also showed very low, probably physiologically insignificant, levels of Delta5 desaturase activity, but none of the products showed Delta4 desaturase activity. The cloning and characterization of desaturases from these fish is an important advance, as they are species in which there is a relative wealth of data on the nutritional regulation of fatty acid desaturation and HUFA synthesis, and between which substantive differences occur.

Authors+Show Affiliations

Institute of Aquaculture, University of Stirling, Airthrey Road, Stirling FK9 4LA, Scotland, United Kingdom.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

15465674

Citation

Zheng, X, et al. "Characterization and Comparison of Fatty Acyl Delta6 Desaturase cDNAs From Freshwater and Marine Teleost Fish Species." Comparative Biochemistry and Physiology. Part B, Biochemistry & Molecular Biology, vol. 139, no. 2, 2004, pp. 269-79.
Zheng X, Seiliez I, Hastings N, et al. Characterization and comparison of fatty acyl Delta6 desaturase cDNAs from freshwater and marine teleost fish species. Comp Biochem Physiol B, Biochem Mol Biol. 2004;139(2):269-79.
Zheng, X., Seiliez, I., Hastings, N., Tocher, D. R., Panserat, S., Dickson, C. A., ... Teale, A. J. (2004). Characterization and comparison of fatty acyl Delta6 desaturase cDNAs from freshwater and marine teleost fish species. Comparative Biochemistry and Physiology. Part B, Biochemistry & Molecular Biology, 139(2), pp. 269-79.
Zheng X, et al. Characterization and Comparison of Fatty Acyl Delta6 Desaturase cDNAs From Freshwater and Marine Teleost Fish Species. Comp Biochem Physiol B, Biochem Mol Biol. 2004;139(2):269-79. PubMed PMID: 15465674.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Characterization and comparison of fatty acyl Delta6 desaturase cDNAs from freshwater and marine teleost fish species. AU - Zheng,X, AU - Seiliez,I, AU - Hastings,N, AU - Tocher,D R, AU - Panserat,S, AU - Dickson,C A, AU - Bergot,P, AU - Teale,A J, PY - 2004/05/28/received PY - 2004/07/30/revised PY - 2004/08/03/accepted PY - 2004/10/7/pubmed PY - 2005/6/29/medline PY - 2004/10/7/entrez SP - 269 EP - 79 JF - Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology JO - Comp. Biochem. Physiol. B, Biochem. Mol. Biol. VL - 139 IS - 2 N2 - Fish are the most important dietary source of the n-3 highly unsaturated fatty acids (HUFA), eicosapentaenoic (EPA) and docosahexaenoic acid (DHA), that have particularly important roles in human nutrition reflecting their roles in critical physiological processes. The objective of the study described here was to clone, functionally characterize and compare expressed fatty acid desaturase genes involved in the production of EPA and DHA in freshwater and marine teleost fish species. Putative fatty acid desaturase cDNAs were isolated and cloned from common carp (Cyprinus carpio) and turbot (Psetta maximus). The enzymic activities of the products of these cDNAs, together with those of cDNAs previously cloned from rainbow trout (Oncorhynchus mykiss) and gilthead sea bream (Sparus aurata), were determined by heterologous expression in the yeast Saccharomyces cerevisiae. The carp and turbot desaturase cDNAs included open reading frames (ORFs) of 1335 and 1338 base pairs, respectively, specifying proteins of 444 and 445 amino acids. The protein sequences possessed all the characteristic features of microsomal fatty acid desaturases, including three histidine boxes, two transmembrane regions, and N-terminal cytochrome b(5) domains containing the haem-binding motif, HPGG. Functional expression showed all four fish cDNAs encode basically unifunctional Delta6 fatty acid desaturase enzymes responsible for the first and rate-limiting step in the biosynthesis of HUFA from 18:3n-3 and 18:2n-6. All the fish desaturases were more active towards the n-3 substrate with 59.5%, 31.5%, 23.1% and 7.0% of 18:3n-3 being converted to 18:4n-3 in the case of turbot, trout, sea bream and carp, respectively. The enzymes also showed very low, probably physiologically insignificant, levels of Delta5 desaturase activity, but none of the products showed Delta4 desaturase activity. The cloning and characterization of desaturases from these fish is an important advance, as they are species in which there is a relative wealth of data on the nutritional regulation of fatty acid desaturation and HUFA synthesis, and between which substantive differences occur. SN - 1096-4959 UR - https://www.unboundmedicine.com/medline/citation/15465674/Characterization_and_comparison_of_fatty_acyl_Delta6_desaturase_cDNAs_from_freshwater_and_marine_teleost_fish_species_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S1096-4959(04)00236-2 DB - PRIME DP - Unbound Medicine ER -