1
|
Skala LE, Philmus B, Mahmud T. Modifications of Protein-Bound Substrates by Trans-Acting Enzymes in Natural Products Biosynthesis. Chembiochem 2024; 25:e202400056. [PMID: 38386898 PMCID: PMC11021167 DOI: 10.1002/cbic.202400056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Revised: 02/21/2024] [Accepted: 02/22/2024] [Indexed: 02/24/2024]
Abstract
Enzymatic modifications of small molecules are a common phenomenon in natural product biosynthesis, leading to the production of diverse bioactive compounds. In polyketide biosynthesis, modifications commonly take place after the completion of the polyketide backbone assembly by the polyketide synthases and the mature products are released from the acyl-carrier protein (ACP). However, exceptions to this rule appear to be widespread, as on-line hydroxylation, methyl transfer, and cyclization during polyketide assembly process are common, particularly in trans-AT PKS systems. Many of these modifications are catalyzed by specific domains within the modular PKS systems. However, several of the on-line modifications are catalyzed by stand-alone proteins. Those include the on-line Baeyer-Villiger oxidation, α-hydroxylation, halogenation, epoxidation, and methyl esterification during polyketide assembly, dehydrogenation of ACP-bound short fatty acids by acyl-CoA dehydrogenase-like enzymes, and glycosylation of ACP-bound intermediates by discrete glycosyltransferase enzymes. This review article highlights some of these trans-acting proteins that catalyze enzymatic modifications of ACP-bound small molecules in natural product biosynthesis.
Collapse
Affiliation(s)
- Leigh E Skala
- Department of Pharmaceutical Sciences, Oregon State University, 203 Pharmacy Building, Corvallis, Oregon, 97331, U.S.A
| | - Benjamin Philmus
- Department of Pharmaceutical Sciences, Oregon State University, 203 Pharmacy Building, Corvallis, Oregon, 97331, U.S.A
| | - Taifo Mahmud
- Department of Pharmaceutical Sciences, Oregon State University, 203 Pharmacy Building, Corvallis, Oregon, 97331, U.S.A
| |
Collapse
|
2
|
Yang R, Wang H, Zhu L, Zhu L, Liu T, Zhang D. Identification and Functional Analysis of Acyl-Acyl Carrier Protein Δ 9 Desaturase from Nannochloropsis oceanica. J Microbiol 2023; 61:95-107. [PMID: 36719619 DOI: 10.1007/s12275-022-00001-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 11/03/2022] [Accepted: 11/08/2022] [Indexed: 02/01/2023]
Abstract
The oleaginous marine microalga Nannochloropsis oceanica strain IMET1 has attracted increasing attention as a promising photosynthetic cell factory due to its unique excellent capacity to accumulate large amounts of triacylglycerols and eicosapentaenoic acid. To complete the genomic annotation for genes in the fatty acid biosynthesis pathway of N. oceanica, we conducted the present study to identify a novel candidate gene encoding the archetypical chloroplast stromal acyl-acyl carrier protein Δ9 desaturase. The full-length cDNA was generated using rapid-amplification of cDNA ends, and the structure of the coding region interrupted by four introns was determined. The RT-qPCR results demonstrated the upregulated transcriptional abundance of this gene under nitrogen starvation condition. Fluorescence localization studies using EGFP-fused protein revealed that the translated protein was localized in chloroplast stroma. The catalytic activity of the translated protein was characterized by inducible expression in Escherichia coli and a mutant yeast strain BY4389, indicating its potential desaturated capacity for palmitoyl-ACP (C16:0-ACP) and stearoyl-ACP (C18:0-ACP). Further functional complementation assay using BY4839 on plate demonstrated that the expressed enzyme restored the biosynthesis of oleic acid. These results support the desaturated activity of the expressed protein in chloroplast stroma to fulfill the biosynthesis and accumulation of monounsaturated fatty acids in N. oceanica strain IMET1.
Collapse
Affiliation(s)
- Ruigang Yang
- Department of Biology and Chemistry, College of Sciences, National University of Defense Technology, Changsha, 410073, People's Republic of China
- Key Laboratory of Biofuels, Key Laboratory of Shandong Energy Biological Genetic Resources, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, People's Republic of China
| | - Hui Wang
- Functional Laboratory of Solar Energy, Shandong Energy Institute, Qingdao, 266101, People's Republic of China
| | - Lingyun Zhu
- Department of Biology and Chemistry, College of Sciences, National University of Defense Technology, Changsha, 410073, People's Republic of China
| | - Lvyun Zhu
- Department of Biology and Chemistry, College of Sciences, National University of Defense Technology, Changsha, 410073, People's Republic of China
| | - Tianzhong Liu
- Key Laboratory of Biofuels, Key Laboratory of Shandong Energy Biological Genetic Resources, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, People's Republic of China.
| | - Dongyi Zhang
- Hunan Key Laboratory of Economic Crops, Genetic Improvement, and Integrated Utilization, School of Life Sciences, Hunan University of Science and Technology, Xiangtan, 411201, People's Republic of China.
| |
Collapse
|
3
|
Halim NFAA, Ali MSM, Leow ATC, Rahman RNZRA. Membrane fatty acid desaturase: biosynthesis, mechanism, and architecture. Appl Microbiol Biotechnol 2022; 106:5957-5972. [PMID: 36063178 DOI: 10.1007/s00253-022-12142-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 08/16/2022] [Accepted: 08/18/2022] [Indexed: 11/25/2022]
Abstract
Fatty acid desaturase catalyzes the desaturation reactions by inserting double bonds into the fatty acyl chain, producing unsaturated fatty acids, which play a vital part in the synthesis of polyunsaturated fatty acids. Though soluble fatty acid desaturases have been described extensively in advanced organisms, there are very limited studies of membrane fatty acid desaturases due to their difficulties in producing a sufficient amount of recombinant desaturases. However, the advancement of technology has shown substantial progress towards the development of elucidating crystal structures of membrane fatty acid desaturase, thus, allowing modification of structure to be manipulated. Understanding the structure, mechanism, and biosynthesis of fatty acid desaturase lay a foundation for the potential production of various strategies associated with alteration and modifications of polyunsaturated fatty acids. This manuscript presents the current state of knowledge and understanding about the structure, mechanisms, and biosynthesis of fatty acid desaturase. In addition, the role of unsaturated fatty acid desaturases in health and diseases is also encompassed. This will be useful in understanding the molecular basis and structural protein of fatty acid desaturase that are significant for the advancement of therapeutic strategies associated with the improvement of health status. KEY POINTS: • Current state of knowledge and understanding about the biosynthesis, mechanisms, and structure of fatty acid desaturase. • The role of unsaturated fatty acid desaturase. • The molecular basis and structural protein elucidated the crystal structure of fatty acid desaturase.
Collapse
Affiliation(s)
- Nur Farah Anis Abd Halim
- Enzyme and Microbial Technology Research Centre, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia
- Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia
| | - Mohd Shukuri Mohamad Ali
- Enzyme and Microbial Technology Research Centre, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia
- Department of Biochemistry, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia
| | - Adam Thean Chor Leow
- Enzyme and Microbial Technology Research Centre, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia
- Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia
| | - Raja Noor Zaliha Raja Abd Rahman
- Enzyme and Microbial Technology Research Centre, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia.
- Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia.
| |
Collapse
|
4
|
Guy JE, Cai Y, Baer MD, Whittle E, Chai J, Yu XH, Lindqvist Y, Raugei S, Shanklin J. Regioselectivity mechanism of the Thunbergia alata Δ6-16:0-acyl carrier protein desaturase. PLANT PHYSIOLOGY 2022; 188:1537-1549. [PMID: 34893899 PMCID: PMC8896614 DOI: 10.1093/plphys/kiab577] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 11/13/2021] [Indexed: 05/12/2023]
Abstract
Plant plastidial acyl-acyl carrier protein (ACP) desaturases are a soluble class of diiron-containing enzymes that are distinct from the diiron-containing integral membrane desaturases found in plants and other organisms. The archetype of this class is the stearoyl-ACP desaturase which converts stearoyl-ACP into oleoyl (18:1Δ9cis)-ACP. Several variants expressing distinct regioselectivity have been described including a Δ6-16:0-ACP desaturase from black-eyed Susan vine (Thunbergia alata). We solved a crystal structure of the T. alata desaturase at 2.05 Å resolution. Using molecular dynamics (MD) simulations, we identified a low-energy complex between 16:0-ACP and the desaturase that would position C6 and C7 of the acyl chain adjacent to the diiron active site. The model complex was used to identify mutant variants that could convert the T. alata Δ6 desaturase to Δ9 regioselectivity. Additional modeling between ACP and the mutant variants confirmed the predicted regioselectivity. To validate the in-silico predictions, we synthesized two variants of the T. alata desaturase and analyzed their reaction products using gas chromatography-coupled mass spectrometry. Assay results confirmed that mutants designed to convert T. alata Δ6 to Δ9 selectivity exhibited the predicted changes. In complementary experiments, variants of the castor desaturase designed to convert Δ9 to Δ6 selectivity lost some of their Δ9 desaturation ability and gained the ability to desaturate at the Δ6 position. The computational workflow for revealing the mechanistic understanding of regioselectivity presented herein lays a foundation for designing acyl-ACP desaturases with novel selectivities to increase the diversity of monoenes available for bioproduct applications.
Collapse
Affiliation(s)
- Jodie E Guy
- Division of Molecular Structural Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, S-171 77 Stockholm, Sweden
| | - Yuanheng Cai
- Biochemistry and Cell Biology Department, Stony Brook University, Stony Brook, New York 11794, USA
| | - Marcel D Baer
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, USA
| | - Edward Whittle
- Brookhaven National Laboratory, Department of Biology, Upton, New York 11973, USA
| | - Jin Chai
- Brookhaven National Laboratory, Department of Biology, Upton, New York 11973, USA
| | - Xiao-Hong Yu
- Biochemistry and Cell Biology Department, Stony Brook University, Stony Brook, New York 11794, USA
| | - Ylva Lindqvist
- Division of Molecular Structural Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, S-171 77 Stockholm, Sweden
| | - Simone Raugei
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, USA
| | - John Shanklin
- Brookhaven National Laboratory, Department of Biology, Upton, New York 11973, USA
- Author for communication:
| |
Collapse
|
5
|
Tupec M, Culka M, Machara A, Macháček S, Bím D, Svatoš A, Rulíšek L, Pichová I. Understanding desaturation/hydroxylation activity of castor stearoyl Δ9-Desaturase through rational mutagenesis. Comput Struct Biotechnol J 2022; 20:1378-1388. [PMID: 35386101 PMCID: PMC8940945 DOI: 10.1016/j.csbj.2022.03.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 03/11/2022] [Accepted: 03/11/2022] [Indexed: 01/17/2023] Open
Abstract
Rationally designed mutations in the Δ9 desaturase promoted hydroxylation activity. Proton and electron transfer to the active site is crucial for the Δ9D to desaturate Detailed analysis of all enzymatic products of the Δ9D was carried out Insight into the chemo-, and stereoselectivity of non-heme diiron enzymes was obtained
A recently proposed reaction mechanism of soluble Δ9 desaturase (Δ9D) allowed us to identify auxiliary residues His203, Asp101, Thr206 and Cys222 localized near the di-iron active site that are supposedly involved in the proton transfer (PT) to and from the active site. The PT, along with the electron transfer (ET), seems to be crucial for efficient desaturation. Thus, perturbing the major PT chains is expected to impair the native reaction and (potentially) amplify minor reaction channels, such as the substrate hydroxylation. To verify this hypothesis, we mutated the four residues mentioned above into their counterparts present in a soluble methane monooxygenase (sMMO), and determined the reaction products of mutants. We found that the mutations significantly promote residual monohydroxylation activities on stearoyl-CoA, often at the expense of native desaturation activity. The favored hydroxylation positions are C9, followed by C10 and C11. Reactions with unsaturated substrate, oleoyl-CoA, yield erythro-9,10-diol, cis-9,10-epoxide and a mixture of allylic alcohols. Additionally, using 9- and 11-hydroxystearoyl-CoA, we showed that the desaturation reaction can proceed only with the hydroxyl group at position C11, whereas the hydroxylation reaction is possible in both cases, i.e. with hydroxyl at position C9 or C11. Despite the fact that the overall outcome of hydroxylation is rather modest and that it is mostly the desaturation/hydroxylation ratio that is affected, our results broaden understanding of the origin of chemo- and stereoselectivity of the Δ9D and provide further insight into the catalytic action of the NHFe2 enzymes.
Collapse
Affiliation(s)
- Michal Tupec
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, Prague 16610, Czech Republic
| | - Martin Culka
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, Prague 16610, Czech Republic
| | - Aleš Machara
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, Prague 16610, Czech Republic
| | - Stanislav Macháček
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, Prague 16610, Czech Republic
| | - Daniel Bím
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, Prague 16610, Czech Republic
| | - Aleš Svatoš
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, Prague 16610, Czech Republic
- Max-Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, Jena 07745, Germany
| | - Lubomír Rulíšek
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, Prague 16610, Czech Republic
- Corresponding authors.
| | - Iva Pichová
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 2, Prague 16610, Czech Republic
- Corresponding authors.
| |
Collapse
|
6
|
Petroff AB, Weir RL, Yates CR, Ng JD, Baudry J. Sequential Dynamics of Stearoyl-CoA Desaturase-1(SCD1)/Ligand Binding and Unbinding Mechanism: A Computational Study. Biomolecules 2021; 11:biom11101435. [PMID: 34680068 PMCID: PMC8533217 DOI: 10.3390/biom11101435] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 09/24/2021] [Accepted: 09/24/2021] [Indexed: 11/17/2022] Open
Abstract
Stearoyl-CoA desaturase-1 (SCD1 or delta-9 desaturase, D9D) is a key metabolic protein that modulates cellular inflammation and stress, but overactivity of SCD1 is associated with diseases, including cancer and metabolic syndrome. This transmembrane endoplasmic reticulum protein converts saturated fatty acids into monounsaturated fatty acids, primarily stearoyl-CoA into oleoyl-CoA, which are critical products for energy metabolism and membrane composition. The present computational molecular dynamics study characterizes the molecular dynamics of SCD1 with substrate, product, and as an apoprotein. The modeling of SCD1:fatty acid interactions suggests that: (1) SCD1:CoA moiety interactions open the substrate-binding tunnel, (2) SCD1 stabilizes a substrate conformation favorable for desaturation, and (3) SCD1:product interactions result in an opening of the tunnel, possibly allowing product exit into the surrounding membrane. Together, these results describe a highly dynamic series of SCD1 conformations resulting from the enzyme:cofactor:substrate interplay that inform drug-discovery efforts.
Collapse
Affiliation(s)
- Anna B. Petroff
- Department of Biological Sciences, The University of Alabama in Huntsville, Huntsville, AL 35899, USA; (A.B.P.); (J.D.N.)
| | - Rebecca L. Weir
- Department of Biochemistry and Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN 37996, USA;
| | - Charles R. Yates
- National Center for Natural Products Research, The University of Mississippi School of Pharmacy, Oxford, MS 38677, USA;
| | - Joseph D. Ng
- Department of Biological Sciences, The University of Alabama in Huntsville, Huntsville, AL 35899, USA; (A.B.P.); (J.D.N.)
| | - Jerome Baudry
- Department of Biological Sciences, The University of Alabama in Huntsville, Huntsville, AL 35899, USA; (A.B.P.); (J.D.N.)
- Correspondence:
| |
Collapse
|
7
|
Shen J, Wu G, Tsai AL, Zhou M. Structure and Mechanism of a Unique Diiron Center in Mammalian Stearoyl-CoA Desaturase. J Mol Biol 2020; 432:5152-5161. [PMID: 32470559 PMCID: PMC7483794 DOI: 10.1016/j.jmb.2020.05.017] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 05/16/2020] [Accepted: 05/22/2020] [Indexed: 12/11/2022]
Abstract
Stearoyl-CoA desaturase 1 (SCD1) is a membrane-embedded metalloenzyme that catalyzes the formation of a double bond on a saturated acyl-CoA. SCD1 has a diiron center and its proper function requires an electron transport chain composed of NADH (or NADPH), cytochrome b5 reductase (b5R), and cytochrome b5 (cyt b5). Since SCD1 is a key regulator in fat metabolism and is required for survival of cancer cells, there is intense interest in targeting SCD1 for various metabolic diseases and cancers. Crystal structures of human and mouse SCD1 were reported recently; however, both proteins have two zinc ions instead of two iron ions in the catalytic center, and as a result, the enzymes are inactive. Here we report a general approach for incorporating iron into heterologously expressed proteins in HEK293 cells. We produced mouse SCD1 that contains a diiron center and visualized its diiron center by solving its crystal structure to 3.5 Å. We assembled the entire electron transport chain using the purified soluble domains of cyt b5 and b5R, and the purified mouse SCD1, and we showed that three proteins coordinate to produce proper products. These results established an in vitro system that allows precise perturbations of the electron transport chain for the understanding of the catalytic mechanism in SCD1.
Collapse
Affiliation(s)
- Jiemin Shen
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Gang Wu
- Division of Hematology, Internal Medicine, University of Texas Medical School at Houston, 6431 Fannin, Houston, TX 77030, USA
| | - Ah-Lim Tsai
- Division of Hematology, Internal Medicine, University of Texas Medical School at Houston, 6431 Fannin, Houston, TX 77030, USA.
| | - Ming Zhou
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.
| |
Collapse
|
8
|
Bím D, Chalupský J, Culka M, Solomon EI, Rulíšek L, Srnec M. Proton-Electron Transfer to the Active Site Is Essential for the Reaction Mechanism of Soluble Δ 9-Desaturase. J Am Chem Soc 2020; 142:10412-10423. [PMID: 32406236 DOI: 10.1021/jacs.0c01786] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
A full understanding of the catalytic action of non-heme iron (NHFe) and non-heme diiron (NHFe2) enzymes is still beyond the grasp of contemporary computational and experimental techniques. Many of these enzymes exhibit fascinating chemo-, regio-, and stereoselectivity, in spite of employing highly reactive intermediates which are necessary for activations of most stable chemical bonds. Herein, we study in detail one intriguing representative of the NHFe2 family of enzymes: soluble Δ9 desaturase (Δ9D), which desaturates rather than performing the thermodynamically favorable hydroxylation of substrate. Its catalytic mechanism has been explored in great detail by using QM(DFT)/MM and multireference wave function methods. Starting from the spectroscopically observed 1,2-μ-peroxo diferric P intermediate, the proton-electron uptake by P is the favored mechanism for catalytic activation, since it allows a significant reduction of the barrier of the initial (and rate-determining) H-atom abstraction from the stearoyl substrate as compared to the "proton-only activated" pathway. Also, we ruled out that a Q-like intermediate (high-valent diamond-core bis-μ-oxo-[FeIV]2 unit) is involved in the reaction mechanism. Our mechanistic picture is consistent with the experimental data available for Δ9D and satisfies fairly stringent conditions required by Nature: the chemo-, stereo-, and regioselectivity of the desaturation of stearic acid. Finally, the mechanisms evaluated are placed into a broader context of NHFe2 chemistry, provided by an amino acid sequence analysis through the families of the NHFe2 enzymes. Our study thus represents an important contribution toward understanding the catalytic action of the NHFe2 enzymes and may inspire further work in NHFe(2) biomimetic chemistry.
Collapse
Affiliation(s)
- Daniel Bím
- J. Heyrovský Institute of Physical Chemistry, The Czech Academy of Sciences, Dolejškova 3, Prague 8 182 23, Czech Republic.,Institute of Organic Chemistry and Biochemistry, The Czech Academy of Sciences, Flemingovo nám. 2, Prague 6 166 10, Czech Republic
| | - Jakub Chalupský
- Institute of Organic Chemistry and Biochemistry, The Czech Academy of Sciences, Flemingovo nám. 2, Prague 6 166 10, Czech Republic
| | - Martin Culka
- Institute of Organic Chemistry and Biochemistry, The Czech Academy of Sciences, Flemingovo nám. 2, Prague 6 166 10, Czech Republic
| | - Edward I Solomon
- Department of Chemistry, Stanford University, 333 Campus Drive, Stanford, California 94305-5080, United States
| | - Lubomír Rulíšek
- Institute of Organic Chemistry and Biochemistry, The Czech Academy of Sciences, Flemingovo nám. 2, Prague 6 166 10, Czech Republic
| | - Martin Srnec
- J. Heyrovský Institute of Physical Chemistry, The Czech Academy of Sciences, Dolejškova 3, Prague 8 182 23, Czech Republic
| |
Collapse
|
9
|
Whittle EJ, Cai Y, Keereetaweep J, Chai J, Buist PH, Shanklin J. Castor Stearoyl-ACP Desaturase Can Synthesize a Vicinal Diol by Dioxygenase Chemistry. PLANT PHYSIOLOGY 2020; 182:730-738. [PMID: 31806737 PMCID: PMC6997704 DOI: 10.1104/pp.19.01111] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 11/20/2019] [Indexed: 05/26/2023]
Abstract
In previous work, we identified a triple mutant of the castor (Ricinus communis) stearoyl-Acyl Carrier Protein desaturase (T117R/G188L/D280K) that, in addition to introducing a double bond into stearate to produce oleate, performed an additional round of oxidation to convert oleate to a trans allylic alcohol acid. To determine the contributions of each mutation, in this work we generated individual castor desaturase mutants carrying residue changes corresponding to those in the triple mutant and investigated their catalytic activities. We observed that T117R, and to a lesser extent D280K, accumulated a novel product, namely erythro-9,10-dihydroxystearate, that we identified via its methyl ester through gas chromatography-mass spectrometry and comparison with authentic standards. The use of 18O2 labeling showed that the oxygens of both hydroxyl moieties originate from molecular oxygen rather than water. Incubation with an equimolar mixture of 18O2 and 16O2 demonstrated that both hydroxyl oxygens originate from a single molecule of O2, proving the product is the result of dioxygenase catalysis. Using prolonged incubation, we discovered that wild-type castor desaturase is also capable of forming erythro-9,10-dihydroxystearate, which presents a likely explanation for its accumulation to ∼0.7% in castor oil, the biosynthetic origin of which had remained enigmatic for decades. In summary, the findings presented here expand the documented constellation of di-iron enzyme catalysis to include a dioxygenase reactivity in which an unactivated alkene is converted to a vicinal diol.
Collapse
Affiliation(s)
- Edward J Whittle
- Biology Department, Brookhaven National Laboratory, Upton, New York 11973
| | - Yuanheng Cai
- Biology Department, Brookhaven National Laboratory, Upton, New York 11973
| | | | - Jin Chai
- Biology Department, Brookhaven National Laboratory, Upton, New York 11973
| | - Peter H Buist
- Department of Chemistry, Carleton University, Ottawa, Ontario, Canada K1S 5B6
| | - John Shanklin
- Biology Department, Brookhaven National Laboratory, Upton, New York 11973
| |
Collapse
|
10
|
Liao HJ, Li J, Huang JL, Davidson M, Kurnikov I, Lin TS, Lee JL, Kurnikova M, Guo Y, Chan NL, Chang WC. Insights into the Desaturation of Cyclopeptin and its C3 Epimer Catalyzed by a non-Heme Iron Enzyme: Structural Characterization and Mechanism Elucidation. Angew Chem Int Ed Engl 2018; 57:1831-1835. [PMID: 29314482 DOI: 10.1002/anie.201710567] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 12/04/2017] [Indexed: 11/08/2022]
Abstract
AsqJ, an iron(II)- and 2-oxoglutarate-dependent enzyme found in viridicatin-type alkaloid biosynthetic pathways, catalyzes sequential desaturation and epoxidation to produce cyclopenins. Crystal structures of AsqJ bound to cyclopeptin and its C3 epimer are reported. Meanwhile, a detailed mechanistic study was carried out to decipher the desaturation mechanism. These findings suggest that a pathway involving hydrogen atom abstraction at the C10 position of the substrate by a short-lived FeIV -oxo species and the subsequent formation of a carbocation or a hydroxylated intermediate is preferred during AsqJ-catalyzed desaturation.
Collapse
Affiliation(s)
- Hsuan-Jen Liao
- Institute of Biochemistry and Molecular Biology, College of Medicine, National (Taiwan) University, Taipei, 100, Taiwan
| | - Jikun Li
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - Jhih-Liang Huang
- Department of Chemistry, North Carolina State University, Raleigh, NC, 27695, USA
| | - Madison Davidson
- Department of Chemistry, North Carolina State University, Raleigh, NC, 27695, USA
| | - Igor Kurnikov
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - Te-Sheng Lin
- Institute of Biochemistry and Molecular Biology, College of Medicine, National (Taiwan) University, Taipei, 100, Taiwan
| | - Justin L Lee
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - Maria Kurnikova
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - Yisong Guo
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - Nei-Li Chan
- Institute of Biochemistry and Molecular Biology, College of Medicine, National (Taiwan) University, Taipei, 100, Taiwan
| | - Wei-Chen Chang
- Department of Chemistry, North Carolina State University, Raleigh, NC, 27695, USA
| |
Collapse
|
11
|
Liao HJ, Li J, Huang JL, Davidson M, Kurnikov I, Lin TS, Lee JL, Kurnikova M, Guo Y, Chan NL, Chang WC. Insights into the Desaturation of Cyclopeptin and its C3 Epimer Catalyzed by a non-Heme Iron Enzyme: Structural Characterization and Mechanism Elucidation. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201710567] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Hsuan-Jen Liao
- Institute of Biochemistry and Molecular Biology; College of Medicine; National (Taiwan) University; Taipei 100 Taiwan
| | - Jikun Li
- Department of Chemistry; Carnegie Mellon University; Pittsburgh PA 15213 USA
| | - Jhih-Liang Huang
- Department of Chemistry; North Carolina State University; Raleigh NC 27695 USA
| | - Madison Davidson
- Department of Chemistry; North Carolina State University; Raleigh NC 27695 USA
| | - Igor Kurnikov
- Department of Chemistry; Carnegie Mellon University; Pittsburgh PA 15213 USA
| | - Te-Sheng Lin
- Institute of Biochemistry and Molecular Biology; College of Medicine; National (Taiwan) University; Taipei 100 Taiwan
| | - Justin L. Lee
- Department of Chemistry; Carnegie Mellon University; Pittsburgh PA 15213 USA
| | - Maria Kurnikova
- Department of Chemistry; Carnegie Mellon University; Pittsburgh PA 15213 USA
| | - Yisong Guo
- Department of Chemistry; Carnegie Mellon University; Pittsburgh PA 15213 USA
| | - Nei-Li Chan
- Institute of Biochemistry and Molecular Biology; College of Medicine; National (Taiwan) University; Taipei 100 Taiwan
| | - Wei-chen Chang
- Department of Chemistry; North Carolina State University; Raleigh NC 27695 USA
| |
Collapse
|
12
|
Ding BJ, Carraher C, Löfstedt C. Sequence variation determining stereochemistry of a Δ11 desaturase active in moth sex pheromone biosynthesis. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2016; 74:68-75. [PMID: 27163509 DOI: 10.1016/j.ibmb.2016.05.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Revised: 04/17/2016] [Accepted: 05/05/2016] [Indexed: 06/05/2023]
Abstract
A Δ11 desaturase from the oblique banded leaf roller moth Choristoneura rosaceana takes the saturated myristic acid and produces a mixture of (E)-11-tetradecenoate and (Z)-11-tetradecenoate with an excess of the Z isomer (35:65). A desaturase from the spotted fireworm moth Choristoneura parallela also operates on myristic acid substrate but produces almost pure (E)-11-tetradecenoate. The two desaturases share 92% amino acid identity and 97% amino acid similarity. There are 24 amino acids differing between these two desaturases. We constructed mutations at all of these positions to pinpoint the sites that determine the product stereochemistry. We demonstrated with a yeast functional assay that one amino acid at the cytosolic carboxyl terminus of the protein (258E) is critical for the Z activity of the C. rosaceana desaturase. Mutating the glutamic acid (E) into aspartic acid (D) transforms the C. rosaceana enzyme into a desaturase with C. parallela-like activity, whereas the reciprocal mutation of the C. parallela desaturase transformed it into an enzyme producing an intermediate 64:36 E/Z product ratio. We discuss the causal link between this amino acid change and the stereochemical properties of the desaturase and the role of desaturase mutations in pheromone evolution.
Collapse
Affiliation(s)
- Bao-Jian Ding
- Pheromone Group, Department of Biology, Lund University, Sölvegatan 37, SE-22362, Lund, Sweden.
| | - Colm Carraher
- Pheromone Group, Department of Biology, Lund University, Sölvegatan 37, SE-22362, Lund, Sweden
| | - Christer Löfstedt
- Pheromone Group, Department of Biology, Lund University, Sölvegatan 37, SE-22362, Lund, Sweden
| |
Collapse
|
13
|
Zhang GL, Zhu Y, Fu WD, Wang P, Zhang RH, Zhang YL, Song Z, Xia GX, Wu JH. iTRAQ Protein Profile Differential Analysis of Dormant and Germinated Grassbur Twin Seeds Reveals that Ribosomal Synthesis and Carbohydrate Metabolism Promote Germination Possibly Through the PI3K Pathway. PLANT & CELL PHYSIOLOGY 2016; 57:1244-1256. [PMID: 27296714 DOI: 10.1093/pcp/pcw074] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 04/03/2016] [Indexed: 06/06/2023]
Abstract
Grassbur is a destructive and invasive weed in pastures, and its burs can cause gastric damage to animals. The strong adaptability and reproductive potential of grassbur are partly due to a unique germination mechanism whereby twin seeds develop in a single bur: one seed germinates, but the other remains dormant. To investigate the molecular mechanism of seed germination in twin seeds, we used isobaric tags for relative and absolute quantitation (iTRAQ) to perform a dynamic proteomic analysis of germination and dormancy. A total of 1,984 proteins were identified, 161 of which were considered to be differentially accumulated. The differentially accumulated proteins comprised 102 up-regulated and 59 down-regulated proteins. These proteins were grouped into seven functional categories, ribosomal proteins being the predominant group. The authenticity and accuracy of the results were confirmed by enzyme-linked immunosorbent assay (ELISA) and quantitative real-time reverse transcription-PCR (qPCR). A dynamic proteomic analysis revealed that ribosome synthesis and carbohydrate metabolism affect seed germination possibly through the phosphoinositide 3-kinase (PI3K) pathway. As the PI3K pathway is generally activated by insulin, analyses of seeds treated with exogenous insulin by qPCR, ELISA and iTRAQ confirmed that the PI3K pathway can be activated, which suppresses dormancy and promotes germination in twin grassbur seeds. Together, these results show that the PI3K pathway may play roles in stimulating seed germination in grassbur by modulating ribosomal synthesis and carbohydrate metabolism.
Collapse
Affiliation(s)
- Guo-Liang Zhang
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, 10081, China
| | - Yue Zhu
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, 10081, China The State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Wei-Dong Fu
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, 10081, China
| | - Peng Wang
- The State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Rui-Hai Zhang
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, 10081, China
| | - Yan-Lei Zhang
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, 10081, China
| | - Zhen Song
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, 10081, China
| | - Gui-Xian Xia
- The State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Jia-He Wu
- The State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| |
Collapse
|
14
|
Nichol T, Murrell JC, Smith TJ. Controlling the Activities of the Diiron Centre in Bacterial Monooxygenases: Lessons from Mutagenesis and Biodiversity. Eur J Inorg Chem 2015. [DOI: 10.1002/ejic.201500043] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Tim Nichol
- Biomedical Research Centre, Sheffield Hallam University, Howard Street, Sheffield S1 1WB, UK, http://www.shu.ac.uk/research/bmrc/staff/professor‐tom‐smith
| | - J. Colin Murrell
- School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
| | - Thomas J. Smith
- Biomedical Research Centre, Sheffield Hallam University, Howard Street, Sheffield S1 1WB, UK, http://www.shu.ac.uk/research/bmrc/staff/professor‐tom‐smith
| |
Collapse
|
15
|
Zhang Y, Maximova SN, Guiltinan MJ. Characterization of a stearoyl-acyl carrier protein desaturase gene family from chocolate tree, Theobroma cacao L. FRONTIERS IN PLANT SCIENCE 2015; 6:239. [PMID: 25926841 PMCID: PMC4396352 DOI: 10.3389/fpls.2015.00239] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 03/25/2015] [Indexed: 05/07/2023]
Abstract
In plants, the conversion of stearoyl-ACP to oleoyol-ACP is catalyzed by a plastid-localized soluble stearoyl-acyl carrier protein (ACP) desaturase (SAD). The activity of SAD significantly impacts the ratio of saturated and unsaturated fatty acids, and is thus a major determinant of fatty acid composition. The cacao genome contains eight putative SAD isoforms with high amino acid sequence similarities and functional domain conservation with SAD genes from other species. Sequence variation in known functional domains between different SAD family members suggested that these eight SAD isoforms might have distinct functions in plant development, a hypothesis supported by their diverse expression patterns in various cacao tissues. Notably, TcSAD1 is universally expressed across all the tissues, and its expression pattern in seeds is highly correlated with the dramatic change in fatty acid composition during seed maturation. Interestingly, TcSAD3 and TcSAD4 appear to be exclusively and highly expressed in flowers, functions of which remain unknown. To test the function of TcSAD1 in vivo, transgenic complementation of the Arabidopsis ssi2 mutant was performed, demonstrating that TcSAD1 successfully rescued all AtSSI2 related phenotypes further supporting the functional orthology between these two genes. The identification of the major SAD gene responsible for cocoa butter biosynthesis provides new strategies for screening for novel genotypes with desirable fatty acid compositions, and for use in breeding programs to help pyramid genes for quality and other traits such as disease resistance.
Collapse
Affiliation(s)
- Yufan Zhang
- Huck Institutes of the Life Sciences, The Pennsylvania State University, University ParkPA, USA
- Department of Plant Science, The Pennsylvania State University, University ParkPA, USA
| | - Siela N. Maximova
- Huck Institutes of the Life Sciences, The Pennsylvania State University, University ParkPA, USA
- Department of Plant Science, The Pennsylvania State University, University ParkPA, USA
| | - Mark J. Guiltinan
- Huck Institutes of the Life Sciences, The Pennsylvania State University, University ParkPA, USA
- Department of Plant Science, The Pennsylvania State University, University ParkPA, USA
- *Correspondence: Mark J. Guiltinan, Huck Institutes of the Life Sciences, Department of Plant Science, The Pennsylvania State University, University Park, 422 Life Sciences Building, PA 16802, USA
| |
Collapse
|
16
|
Ang KC, Ibrahim P, Gam LH. Analysis of differentially expressed proteins in late-stationary growth phase of Mycobacterium tuberculosis H37Rv. Biotechnol Appl Biochem 2013; 61:153-64. [PMID: 23826872 DOI: 10.1002/bab.1137] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Accepted: 06/23/2013] [Indexed: 11/09/2022]
Abstract
Mycobacterium tuberculosis is a causative agent of tuberculosis (TB). The ability of M. tuberculosis to be quiescent in the cell has caused the emergence of latent infection. A comprehensive proteomic analysis of M. tuberculosis H37Rv over three growth phases, namely mid-log (14-day culture), early stationary (28-day culture), and late stationary (50-day culture), was performed in order to study the change in proteome from the mid-log phase to late-stationary phase. Combination methods of two-dimensional electrophoresis (2-DE) and tandem mass spectrometry were used to generate proteome maps of M. tuberculosis at different growth phases. Ten proteins were detected differentially expressed in the late-stationary phase compared with the other two phases. These proteins were SucD, TrpD, and Rv2161c, which belong to metabolic pathway proteins; FadE5, AccD5, DesA1, and Rv1139c are proteins involved in cell wall or lipid biosynthesis, whereas TB21.7 and Rv3224 are conserved hypothetical proteins with unknown function. A surface antigen protein, DesA1, was not detectable in the late-stationary phase, although present in both log and early-stationary phases. The changes in the expression levels of these proteins were in line with the growth environment changes of the bacteria from mid-log phase to late-stationary phase. The information gathered may be valuable in the intervention against latent TB infection.
Collapse
Affiliation(s)
- Kai-Cheen Ang
- School of Pharmaceutical Sciences, University Sains Malaysia, Minden, Penang, Malaysia
| | | | | |
Collapse
|
17
|
Vanhercke T, Wood CC, Stymne S, Singh SP, Green AG. Metabolic engineering of plant oils and waxes for use as industrial feedstocks. PLANT BIOTECHNOLOGY JOURNAL 2013. [PMID: 23190163 DOI: 10.1111/pbi.12023] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Society has come to rely heavily on mineral oil for both energy and petrochemical needs. Plant lipids are uniquely suited to serve as a renewable source of high-value fatty acids for use as chemical feedstocks and as a substitute for current petrochemicals. Despite the broad variety of acyl structures encountered in nature and the cloning of many genes involved in their biosynthesis, attempts at engineering economic levels of specialty industrial fatty acids in major oilseed crops have so far met with only limited success. Much of the progress has been hampered by an incomplete knowledge of the fatty acid biosynthesis and accumulation pathways. This review covers new insights based on metabolic flux and reverse engineering studies that have changed our view of plant oil synthesis from a mostly linear process to instead an intricate network with acyl fluxes differing between plant species. These insights are leading to new strategies for high-level production of industrial fatty acids and waxes. Furthermore, progress in increasing the levels of oil and wax structures in storage and vegetative tissues has the potential to yield novel lipid production platforms. The challenge and opportunity for the next decade will be to marry these technologies when engineering current and new crops for the sustainable production of oil and wax feedstocks.
Collapse
|
18
|
Cooper HLR, Mishra G, Huang X, Pender-Cudlip M, Austin RN, Shanklin J, Groves JT. Parallel and competitive pathways for substrate desaturation, hydroxylation, and radical rearrangement by the non-heme diiron hydroxylase AlkB. J Am Chem Soc 2012; 134:20365-75. [PMID: 23157204 PMCID: PMC3531984 DOI: 10.1021/ja3059149] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A purified and highly active form of the non-heme diiron hydroxylase AlkB was investigated using the diagnostic probe substrate norcarane. The reaction afforded C2 (26%) and C3 (43%) hydroxylation and desaturation products (31%). Initial C-H cleavage at C2 led to 7% C2 hydroxylation and 19% 3-hydroxymethylcyclohexene, a rearrangement product characteristic of a radical rearrangement pathway. A deuterated substrate analogue, 3,3,4,4-norcarane-d(4), afforded drastically reduced amounts of C3 alcohol (8%) and desaturation products (5%), while the radical rearranged alcohol was now the major product (65%). This change in product ratios indicates a large kinetic hydrogen isotope effect of ∼20 for both the C-H hydroxylation at C3 and the desaturation pathway, with all of the desaturation originating via hydrogen abstraction at C3 and not C2. The data indicate that AlkB reacts with norcarane via initial C-H hydrogen abstraction from C2 or C3 and that the three pathways, C3 hydroxylation, C3 desaturation, and C2 hydroxylation/radical rearrangement, are parallel and competitive. Thus, the incipient radical at C3 either reacts with the iron-oxo center to form an alcohol or proceeds along the desaturation pathway via a second H-abstraction to afford both 2-norcarene and 3-norcarene. Subsequent reactions of these norcarenes lead to detectable amounts of hydroxylation products and toluene. By contrast, the 2-norcaranyl radical intermediate leads to C2 hydroxylation and the diagnostic radical rearrangement, but this radical apparently does not afford desaturation products. The results indicate that C-H hydroxylation and desaturation follow analogous stepwise reaction channels via carbon radicals that diverge at the product-forming step.
Collapse
Affiliation(s)
| | - Girish Mishra
- Department of Biology, Brookhaven National Laboratory, 50 Bell Avenue, Upton, NY 11973
| | - Xiongyi Huang
- Department of Chemistry, Princeton University, Princeton NJ 08544
| | | | | | - John Shanklin
- Department of Biology, Brookhaven National Laboratory, 50 Bell Avenue, Upton, NY 11973
| | - John T. Groves
- Department of Chemistry, Princeton University, Princeton NJ 08544
| |
Collapse
|
19
|
Cho KB, Wu X, Lee YM, Kwon YH, Shaik S, Nam W. Evidence for an Alternative to the Oxygen Rebound Mechanism in C–H Bond Activation by Non-Heme FeIVO Complexes. J Am Chem Soc 2012. [DOI: 10.1021/ja308290r] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Kyung-Bin Cho
- Department of Bioinspired Science
and Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Korea
| | - Xiujuan Wu
- Department of Bioinspired Science
and Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Korea
| | - Yong-Min Lee
- Department of Bioinspired Science
and Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Korea
| | - Yoon Hye Kwon
- Department of Bioinspired Science
and Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Korea
| | - Sason Shaik
- Institute of Chemistry and The
Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem,
Israel
| | - Wonwoo Nam
- Department of Bioinspired Science
and Department of Chemistry and Nano Science, Ewha Womans University, Seoul 120-750, Korea
| |
Collapse
|
20
|
Cytotoxic petrosiacetylenes from the marine sponge Petrosia sp. Lipids 2012; 48:87-91. [PMID: 23077003 DOI: 10.1007/s11745-012-3727-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Accepted: 09/24/2012] [Indexed: 10/27/2022]
Abstract
A novel petrosiacetylene analog (petrosiacetylene E) has been isolated from the Korean marine sponge Petrosia sp., along with petrosiacetylene A, B and C. Their structures were elucidated on the basis of spectroscopic methods and the stereochemistry of the new compound was determined by using the modified Mosher's method. Petrosiacetylene E showed higher cytotoxicity against five human cancer cell lines than petrosiacetylene A and B, presumably due to the additional hydroxy group located at C-16.
Collapse
|
21
|
Mas-Ballesté R, McDonald AR, Reed D, Usharani D, Schyman P, Milko P, Shaik S, Que L. Intramolecular gas-phase reactions of synthetic nonheme oxoiron(IV) ions: proximity and spin-state reactivity rules. Chemistry 2012; 18:11747-60. [PMID: 22837063 DOI: 10.1002/chem.201200105] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Revised: 03/16/2012] [Indexed: 11/11/2022]
Abstract
The intramolecular gas-phase reactivity of four oxoiron(IV) complexes supported by tetradentate N(4) ligands (L) has been studied by means of tandem mass spectrometry measurements in which the gas-phase ions [Fe(IV)(O)(L)(OTf)](+) (OTf = trifluoromethanesulfonate) and [Fe(IV) (O)(L)](2+) were isolated and then allowed to fragment by collision-induced decay (CID). CID fragmentation of cations derived from oxoiron(IV) complexes of 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane (tmc) and N,N'-bis(2-pyridylmethyl)-1,5-diazacyclooctane (L(8)Py(2)) afforded the same predominant products irrespective of whether they were hexacoordinate or pentacoordinate. These products resulted from the loss of water by dehydrogenation of ethylene or propylene linkers on the tetradentate ligand. In contrast, CID fragmentation of ions derived from oxoiron(IV) complexes of linear tetradentate ligands N,N'-bis(2-pyridylmethyl)-1,2-diaminoethane (bpmen) and N,N'-bis(2-pyridylmethyl)-1,3-diaminopropane (bpmpn) showed predominant oxidative N-dealkylation for the hexacoordinate [Fe(IV)(O)(L)(OTf)](+) cations and predominant dehydrogenation of the diaminoethane/propane backbone for the pentacoordinate [Fe(IV)(O)(L)](2+) cations. DFT calculations on [Fe(IV)(O)(bpmen)] ions showed that the experimentally observed preference for oxidative N-dealkylation versus dehydrogenation of the diaminoethane linker for the hexa- and pentacoordinate ions, respectively, is dictated by the proximity of the target C-H bond to the oxoiron(IV) moiety and the reactive spin state. Therefore, there must be a difference in ligand topology between the two ions. More importantly, despite the constraints on the geometries of the TS that prohibit the usual upright σ trajectory and prevent optimal σ(CH)-σ*(z2) overlap, all the reactions still proceed preferentially on the quintet (S = 2) state surface, which increases the number of exchange interactions in the d block of iron and leads thereby to exchange enhanced reactivity (EER). As such, EER is responsible for the dominance of the S = 2 reactions for both hexa- and pentacoordinate complexes.
Collapse
Affiliation(s)
- Rubén Mas-Ballesté
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, MN 55455, USA
| | | | | | | | | | | | | | | |
Collapse
|
22
|
Bhar P, Reed DW, Covello PS, Buist PH. Topological Study of Mechanistic Diversity in Conjugated Fatty Acid Biosynthesis. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201202080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
23
|
Bhar P, Reed DW, Covello PS, Buist PH. Topological study of mechanistic diversity in conjugated fatty acid biosynthesis. Angew Chem Int Ed Engl 2012; 51:6686-90. [PMID: 22623346 DOI: 10.1002/anie.201202080] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Indexed: 11/11/2022]
Affiliation(s)
- Palash Bhar
- Department of Chemistry, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada
| | | | | | | |
Collapse
|
24
|
Rawat R, Yu XH, Sweet M, Shanklin J. Conjugated fatty acid synthesis: residues 111 and 115 influence product partitioning of Momordica charantia conjugase. J Biol Chem 2012; 287:16230-7. [PMID: 22451660 DOI: 10.1074/jbc.m111.325316] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Conjugated linolenic acids (CLNs), 18:3 Δ(9,11,13), lack the methylene groups found between the double bonds of linolenic acid (18:3 Δ(9,12,15)). CLNs are produced by conjugase enzymes that are homologs of the oleate desaturases FAD2. The goal of this study was to map the domain(s) within the Momordica charantia conjugase (FADX) responsible for CLN formation. To achieve this, a series of Momordica FADX-Arabidopsis FAD2 chimeras were expressed in the Arabidopsis fad3fae1 mutant, and the transformed seeds were analyzed for the accumulation of CLN. These experiments identified helix 2 and the first histidine box as a determinant of conjugase product partitioning into punicic acid (18:3 Δ(9cis,11trans,13cis)) or α-eleostearic acid (18:3 Δ(9cis,11trans,13trans)). This was confirmed by analysis of a FADX mutant containing six substitutions in which the sequence of helix 2 and first histidine box was converted to that of FAD2. Each of the six FAD2 substitutions was individually converted back to the FADX equivalent identifying residues 111 and 115, adjacent to the first histidine box, as key determinants of conjugase product partitioning. Additionally, expression of FADX G111V and FADX G111V/D115E resulted in an approximate doubling of eleostearic acid accumulation to 20.4% and 21.2%, respectively, compared with 9.9% upon expression of the native Momordica FADX. Like the Momordica conjugase, FADX G111V and FADX D115E produced predominantly α-eleostearic acid and little punicic acid, but the FADX G111V/D115E double mutant produced approximately equal amounts of α-eleostearic acid and its isomer, punicic acid, implicating an interactive effect of residues 111 and 115 in punicic acid formation.
Collapse
Affiliation(s)
- Richa Rawat
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York 11794, USA
| | | | | | | |
Collapse
|
25
|
Bacterial degradation of tert-amyl alcohol proceeds via hemiterpene 2-methyl-3-buten-2-ol by employing the tertiary alcohol desaturase function of the Rieske nonheme mononuclear iron oxygenase MdpJ. J Bacteriol 2011; 194:972-81. [PMID: 22194447 DOI: 10.1128/jb.06384-11] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Tertiary alcohols, such as tert-butyl alcohol (TBA) and tert-amyl alcohol (TAA) and higher homologues, are only slowly degraded microbially. The conversion of TBA seems to proceed via hydroxylation to 2-methylpropan-1,2-diol, which is further oxidized to 2-hydroxyisobutyric acid. By analogy, a branched pathway is expected for the degradation of TAA, as this molecule possesses several potential hydroxylation sites. In Aquincola tertiaricarbonis L108 and Methylibium petroleiphilum PM1, a likely candidate catalyst for hydroxylations is the putative tertiary alcohol monooxygenase MdpJ. However, by comparing metabolite accumulations in wild-type strains of L108 and PM1 and in two mdpJ knockout mutants of strain L108, we could clearly show that MdpJ is not hydroxylating TAA to diols but functions as a desaturase, resulting in the formation of the hemiterpene 2-methyl-3-buten-2-ol. The latter is further processed via the hemiterpenes prenol, prenal, and 3-methylcrotonic acid. Likewise, 3-methyl-3-pentanol is degraded via 3-methyl-1-penten-3-ol. Wild-type strain L108 and mdpJ knockout mutants formed isoamylene and isoprene from TAA and 2-methyl-3-buten-2-ol, respectively. It is likely that this dehydratase activity is catalyzed by a not-yet-characterized enzyme postulated for the isomerization of 2-methyl-3-buten-2-ol and prenol. The vitamin requirements of strain L108 growing on TAA and the occurrence of 3-methylcrotonic acid as a metabolite indicate that TAA and hemiterpene degradation are linked with the catabolic route of the amino acid leucine, including an involvement of the biotin-dependent 3-methylcrotonyl coenzyme A (3-methylcrotonyl-CoA) carboxylase LiuBD. Evolutionary aspects of favored desaturase versus hydroxylation pathways for TAA conversion and the possible role of MdpJ in the degradation of higher tertiary alcohols are discussed.
Collapse
|
26
|
Remote control of regioselectivity in acyl-acyl carrier protein-desaturases. Proc Natl Acad Sci U S A 2011; 108:16594-9. [PMID: 21930947 DOI: 10.1073/pnas.1110221108] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Regiospecific desaturation of long-chain saturated fatty acids has been described as approaching the limits of the discriminatory power of enzymes because the substrate entirely lacks distinguishing features close to the site of dehydrogenation. To identify the elusive mechanism underlying regioselectivity, we have determined two crystal structures of the archetypal Δ9 desaturase from castor in complex with acyl carrier protein (ACP), which show the bound ACP ideally situated to position C9 and C10 of the acyl chain adjacent to the diiron active site for Δ9 desaturation. Analysis of the structures and modeling of the complex between the highly homologous ivy Δ4 desaturase and ACP, identified a residue located at the entrance to the binding cavity, Asp280 in the castor desaturase (Lys275 in the ivy desaturase), which is strictly conserved within Δ9 and Δ4 enzymes but differs between them. We hypothesized that interaction between Lys275 and the phosphate of the pantetheine, seen in the ivy model, is key to positioning C4 and C5 adjacent to the diiron center for Δ4 desaturation. Mutating castor Asp280 to Lys resulted in a major shift from Δ9 to Δ4 desaturation. Thus, interaction between desaturase side-chain 280 and phospho-serine 38 of ACP, approximately 27 Å from the site of double-bond formation, predisposes ACP binding that favors either Δ9 or Δ4 desaturation via repulsion (acidic side chain) or attraction (positively charged side chain), respectively. Understanding the mechanism underlying remote control of regioselectivity provides the foundation for reengineering desaturase enzymes to create designer chemical feedstocks that would provide alternatives to those currently obtained from petrochemicals.
Collapse
|
27
|
Formation of alkenes via degradation of tert-alkyl ethers and alcohols by Aquincola tertiaricarbonis L108 and Methylibium spp. Appl Environ Microbiol 2011; 77:5981-7. [PMID: 21742915 DOI: 10.1128/aem.00093-11] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacterial degradation pathways of fuel oxygenates such as methyl tert-butyl and tert-amyl methyl ether (MTBE and TAME, respectively) have already been studied in some detail. However, many of the involved enzymes are still unknown, and possible side reactions have not yet been considered. In Aquincola tertiaricarbonis L108, Methylibium petroleiphilum PM1, and Methylibium sp. strain R8, we have now detected volatile hydrocarbons as by-products of the degradation of the tert-alkyl ether metabolites tert-butyl and tert-amyl alcohol (TBA and TAA, respectively). The alkene isobutene was formed only during TBA catabolism, while the beta and gamma isomers of isoamylene were produced only during TAA conversion. Both tert-alkyl alcohol degradation and alkene production were strictly oxygen dependent. However, the relative contribution of the dehydration reaction to total alcohol conversion increased with decreasing oxygen concentrations. In resting-cell experiments where the headspace oxygen content was adjusted to less than 2%, more than 50% of the TAA was converted to isoamylene. Isobutene formation from TBA was about 20-fold lower, reaching up to 4% alcohol turnover at low oxygen concentrations. It is likely that the putative tert-alkyl alcohol monooxygenase MdpJ, belonging to the Rieske nonheme mononuclear iron enzymes and found in all three strains tested, or an associated enzymatic step catalyzed the unusual elimination reaction. This was also supported by the detection of mdpJK genes in MTBE-degrading and isobutene-emitting enrichment cultures obtained from two treatment ponds operating at Leuna, Germany. The possible use of alkene formation as an easy-to-measure indicator of aerobic fuel oxygenate biodegradation in contaminated aquifers is discussed.
Collapse
|
28
|
Vanhercke T, Shrestha P, Green AG, Singh SP. Mechanistic and structural insights into the regioselectivity of an acyl-CoA fatty acid desaturase via directed molecular evolution. J Biol Chem 2011; 286:12860-9. [PMID: 21300802 PMCID: PMC3075633 DOI: 10.1074/jbc.m110.191098] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2010] [Revised: 02/03/2011] [Indexed: 11/06/2022] Open
Abstract
Membrane-bound fatty acid desaturases and related enzymes play a pivotal role in the biosynthesis of unsaturated and various unusual fatty acids. Structural insights into the remarkable catalytic diversity and wide range of substrate specificities of this class of enzymes remain limited due to the lack of a crystal structure. To investigate the structural basis of the double bond positioning (regioselectivity) of the desaturation reaction in more detail, we relied on a combination of directed evolution in vitro and a powerful yeast complementation assay to screen for Δx regioselectivity. After two selection rounds, variants of the bifunctional Δ12/Δ9-desaturase from the house cricket (Acheta domesticus) exhibited increased Δ9-desaturation activity on shorter chain fatty acids. This change in specificity was the result of as few as three mutations, some of them near the putative active site. Subsequent analysis of individual substitutions revealed an important role of residue Phe-52 in facilitating Δ9-desaturation of shorter chain acyl substrates and allowed for the redesign of the cricket Δ12/Δ9-desaturase into a 16:0-specific Δ9-desaturase. Our results demonstrate that a minimal number of mutations can have a profound impact on the regioselectivity of acyl-CoA fatty acid desaturases and include the first biochemical data supporting the acyl-CoA acyl carrier specificity of a desaturase able to carry out Δ12-desaturation.
Collapse
Affiliation(s)
- Thomas Vanhercke
- From the Commonwealth Scientific and Industrial Research Organisation (CSIRO) Plant Industry, Canberra, Australian Capital Territory 2601, Australia
| | - Pushkar Shrestha
- From the Commonwealth Scientific and Industrial Research Organisation (CSIRO) Plant Industry, Canberra, Australian Capital Territory 2601, Australia
| | - Allan G. Green
- From the Commonwealth Scientific and Industrial Research Organisation (CSIRO) Plant Industry, Canberra, Australian Capital Territory 2601, Australia
| | - Surinder P. Singh
- From the Commonwealth Scientific and Industrial Research Organisation (CSIRO) Plant Industry, Canberra, Australian Capital Territory 2601, Australia
| |
Collapse
|
29
|
Stearoyl-acyl carrier protein desaturases are associated with floral isolation in sexually deceptive orchids. Proc Natl Acad Sci U S A 2011; 108:5696-701. [PMID: 21436056 DOI: 10.1073/pnas.1013313108] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The orchids Ophrys sphegodes and O. exaltata are reproductively isolated from each other by the attraction of two different, highly specific pollinator species. For pollinator attraction, flowers chemically mimic the pollinators' sex pheromones, the key components of which are alkenes with different double-bond positions. This study identifies genes likely involved in alkene biosynthesis, encoding stearoyl-acyl carrier protein (ACP) desaturase (SAD) homologs. The expression of two isoforms, SAD1 and SAD2, is flower-specific and broadly parallels alkene production during flower development. SAD2 shows a significant association with alkene production, and in vitro assays show that O. sphegodes SAD2 has activity both as an 18:0-ACP Δ(9) and a 16:0-ACP Δ(4) desaturase. Downstream metabolism of the SAD2 reaction products would give rise to alkenes with double-bonds at position 9 or position 12, matching double-bond positions observed in alkenes in the odor bouquet of O. sphegodes. SAD1 and SAD2 show evidence of purifying selection before, and positive or relaxed purifying selection after gene duplication. By contributing to the production of species-specific alkene bouquets, SAD2 is suggested to contribute to differential pollinator attraction and reproductive isolation among these species. Taken together, these data are consistent with the hypothesis that SAD2 is a florally expressed barrier gene of large phenotypic effect and, possibly, a genic target of pollinator-mediated selection.
Collapse
|
30
|
Shanklin J, Guy JE, Mishra G, Lindqvist Y. Desaturases: emerging models for understanding functional diversification of diiron-containing enzymes. J Biol Chem 2009; 284:18559-63. [PMID: 19363032 DOI: 10.1074/jbc.r900009200] [Citation(s) in RCA: 140] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Desaturases and related enzymes perform O(2)-dependent dehydrogenations initiated at unactivated C-H groups with the use of a diiron active site. Determination of the long-sought oxidized desaturase crystal structure facilitated structural comparison of the active sites of disparate diiron enzymes. Experiments on the castor desaturase are discussed that provide experimental support for a hypothesized ancestral oxidase enzyme in the context of the evolution of the diiron enzyme diverse functionality. We also summarize recent analysis of a castor mutant desaturase that provides valuable insights into the relationship of proposed substrate-binding modes with respect to a range of catalytic outcomes.
Collapse
Affiliation(s)
- John Shanklin
- Department of Biology, Brookhaven National Laboratory, Upton, New York 11973, USA.
| | | | | | | |
Collapse
|
31
|
Mukherjee A, Martinho M, Bominaar E, Münck E, Que L. Shape-Selective Interception by Hydrocarbons of the O2-Derived Oxidant of a Biomimetic Nonheme Iron Complex. Angew Chem Int Ed Engl 2009. [DOI: 10.1002/ange.200805342] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
|
32
|
Mukherjee A, Martinho M, Bominaar EL, Münck E, Que L. Shape-selective interception by hydrocarbons of the O2-derived oxidant of a biomimetic nonheme iron complex. Angew Chem Int Ed Engl 2009; 48:1780-3. [PMID: 19180613 PMCID: PMC2719302 DOI: 10.1002/anie.200805342] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Picky ferryl: The complex [Fe(Tp(Ph(2)))(BF)] (Tp(Ph(2)) = hydrotris(3,5-diphenylpyrazolyl)borate; BF = benzoylformate) reacts with O(2) to generate an oxidant (see picture; O red, pink; Fe yellow; N blue; C gray; H white) that oxidizes added hydrocarbons shape-selectively. Discrimination derives from a cleft formed by two phenyl groups of the Tp(Ph(2)) ligand, favoring oblate spheroidal substrates.
Collapse
Affiliation(s)
- Anusree Mukherjee
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455 (USA)
| | - Marlène Martinho
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA 15213 (USA)
| | - Emile L. Bominaar
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA 15213 (USA)
| | - Eckard Münck
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA 15213 (USA)
| | - Lawrence Que
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455 (USA)
| |
Collapse
|