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Cui J, Chen H, Tang X, Zhang H, Chen YQ, Chen W. Consensus mutagenesis and computational simulation provide insight into the desaturation catalytic mechanism for delta 6 fatty acid desaturase. Biochem Biophys Res Commun 2022; 586:74-80. [PMID: 34837835 DOI: 10.1016/j.bbrc.2021.11.050] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 11/14/2021] [Indexed: 12/29/2022]
Abstract
Fatty acid desaturase (FADS) generates double bond at a certain position of the corresponding polyunsaturated fatty acids (PUFAs) with high selectivity, the enzyme activity and PUFAs products of which are essential to biological systems and are associated with a variety of physiological diseases. Little is known about the structure of FADSs and their amino acid residues related to catalytic activities. Identifying key residues of Micromonas pusilla delta 6 desaturase (MpFADS6) provides a point of departure for a better understanding of desaturation. In this study, conserved amino acids were anchored through gene consensus analysis, thereby generating corresponding variants by site-directed mutagenesis. To achieve stable and high-efficiency expression of MpFADS6 and its variants in Saccharomyces cerevisiae, the key points of induced expression were optimized. The contribution of conserved residues to the function of enzyme was determined by analyzing enzyme activity of the variants. Molecular modeling indicated that these residues are essential to catalytic activities, or substrate binding. Mutants MpFADS6[Q409R] and MpFADS6[M242P] abolished desaturation, while MpFADS6[F419V] and MpFADS6[A374Q] significantly reduced catalytic activities. Given that certain residues have been identified to have a significant impact on MpFADS6 activities, it is put forward that histidine-conserved region III of FADS6 is related to electronic transfer during desaturation, while histidine-conserved regions I and II are related to desaturation. These findings provide new insights and methods to determine the structure, mechanism and directed transformation of membrane-bound desaturases.
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Affiliation(s)
- Jie Cui
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, 214122, People's Republic of China; School of Food Science and Technology, Jiangnan University, Wuxi, 214122, PR China.
| | - Haiqin Chen
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, 214122, People's Republic of China; School of Food Science and Technology, Jiangnan University, Wuxi, 214122, PR China.
| | - Xin Tang
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, 214122, People's Republic of China; School of Food Science and Technology, Jiangnan University, Wuxi, 214122, PR China.
| | - Hao Zhang
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, 214122, People's Republic of China; School of Food Science and Technology, Jiangnan University, Wuxi, 214122, PR China; National Engineering Research Center for Functional Food, Jiangnan University, Wuxi, 214122, PR China; Wuxi Translational Medicine Research Center and Jiangsu Translational Medicine Research Institute Wuxi Branch, Wuxi, 214122, PR China.
| | - Yong Q Chen
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, 214122, People's Republic of China; School of Food Science and Technology, Jiangnan University, Wuxi, 214122, PR China; Department of Cancer Biology, Wake Forest School of Medicine, Winston-Salem, NC 5, 27127, USA.
| | - Wei Chen
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, 214122, People's Republic of China; School of Food Science and Technology, Jiangnan University, Wuxi, 214122, PR China; National Engineering Research Center for Functional Food, Jiangnan University, Wuxi, 214122, PR China.
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Haritos VS, Horne I, Damcevski K, Glover K, Gibb N. Unexpected functional diversity in the fatty acid desaturases of the flour beetle Tribolium castaneum and identification of key residues determining activity. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2014; 51:62-70. [PMID: 24880119 DOI: 10.1016/j.ibmb.2014.05.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 05/13/2014] [Accepted: 05/14/2014] [Indexed: 06/03/2023]
Abstract
Desaturases catalyse modifications to fatty acids which are essential to homeostasis and for pheromone and defensive chemical production. All desaturases of the flour beetle Tribolium castaneum were investigated via query of the sequenced genome which yielded 15 putative acyl-Coenzyme A genes. Eleven desaturase mRNA were obtained in full length and functionally expressed in yeast. Phylogenetic analysis separated the desaturases into 4 distinct clades; one clade contained conserved beetle Δ9 desaturases, second clade was Tribolium-specific having diverse activities including Δ5, Δ9 and Δ12 desaturation and the other 2 clades had mixed insect representatives. Three members of this clade contained unusual inserted sequences of ∼20 residues in the C-terminal region and were related to desaturases that all contained similar inserts. Deletion of the entirety of the insert in the flour beetle Δ12 desaturase abolished its activity but this was partially restored by the reintroduction of two histidine residues, suggesting the histidine(s) are required for activity but the full length insert is not. Five new desaturase activities were discovered: Δ9 desaturation of C12:0-C16:0 substrates; two unprecedented Δ5 enzymes acting on C18:0 and C16:0; Δ9 activity exclusively on C16:0 and a further stearate Δ9 desaturase. qPCR analysis ruled out a role in sex pheromone synthesis for the Δ5 and Δ9/C16:0 desaturases. The flour beetle genome has underpinned an examination of all transcribed desaturases in the organism and revealed a diversity of novel and unusual activities, an improved understanding of the evolutionary relationships among insect desaturases and sequence determinants of activity.
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Affiliation(s)
| | - Irene Horne
- CSIRO Ecosystem Sciences, GPO Box 1700, Canberra, ACT, 2601 Australia
| | | | - Karen Glover
- CSIRO Ecosystem Sciences, GPO Box 1700, Canberra, ACT, 2601 Australia
| | - Nerida Gibb
- CSIRO Ecosystem Sciences, GPO Box 1700, Canberra, ACT, 2601 Australia
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Fonseca-Madrigal J, Navarro JC, Hontoria F, Tocher DR, Martínez-Palacios CA, Monroig Ó. Diversification of substrate specificities in teleostei Fads2: characterization of Δ4 and Δ6Δ5 desaturases of Chirostoma estor. J Lipid Res 2014; 55:1408-19. [PMID: 24792929 DOI: 10.1194/jlr.m049791] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Indexed: 11/20/2022] Open
Abstract
Currently existing data show that the capability for long-chain PUFA (LC-PUFA) biosynthesis in teleost fish is more diverse than in other vertebrates. Such diversity has been primarily linked to the subfunctionalization that teleostei fatty acyl desaturase (Fads)2 desaturases have undergone during evolution. We previously showed that Chirostoma estor, one of the few representatives of freshwater atherinopsids, had the ability for LC-PUFA biosynthesis from C18 PUFA precursors, in agreement with this species having unusually high contents of DHA. The particular ancestry and pattern of LC-PUFA biosynthesis activity of C. estor make this species an excellent model for study to gain further insight into LC-PUFA biosynthetic abilities among teleosts. The present study aimed to characterize cDNA sequences encoding fatty acyl elongases and desaturases, key genes involved in the LC-PUFA biosynthesis. Results show that C. estor expresses an elongase of very long-chain FA (Elovl)5 elongase and two Fads2 desaturases displaying Δ4 and Δ6/Δ5 specificities, thus allowing us to conclude that these three genes cover all the enzymatic abilities required for LC-PUFA biosynthesis from C18 PUFA. In addition, the specificities of the C. estor Fads2 enabled us to propose potential evolutionary patterns and mechanisms for subfunctionalization of Fads2 among fish lineages.
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Affiliation(s)
- Jorge Fonseca-Madrigal
- Laboratorio de Acuicultura, Instituto de Investigaciones Agropecuarias y Forestales, Universidad Michoacana de San Nicolás de Hidalgo (UMSNH), Morelia 58330, Michoacán, Mexico
| | - Juan C Navarro
- Instituto de Acuicultura Torre de la Sal-Consejo Superior de Investigaciones Científicas (IATS-CSIC), Ribera de Cabanes 12595, Castellón, Spain
| | - Francisco Hontoria
- Instituto de Acuicultura Torre de la Sal-Consejo Superior de Investigaciones Científicas (IATS-CSIC), Ribera de Cabanes 12595, Castellón, Spain
| | - Douglas R Tocher
- Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling FK9 4LA, Scotland, UK
| | - Carlos A Martínez-Palacios
- Laboratorio de Acuicultura, Instituto de Investigaciones Agropecuarias y Forestales, Universidad Michoacana de San Nicolás de Hidalgo (UMSNH), Morelia 58330, Michoacán, Mexico
| | - Óscar Monroig
- Instituto de Acuicultura Torre de la Sal-Consejo Superior de Investigaciones Científicas (IATS-CSIC), Ribera de Cabanes 12595, Castellón, Spain Laboratorio de Acuicultura, Instituto de Investigaciones Agropecuarias y Forestales, Universidad Michoacana de San Nicolás de Hidalgo (UMSNH), Morelia 58330, Michoacán, Mexico
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