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Kim J, Oh EK, Kim EJ, Lee JK. Photoautotrophic Growth Rate Enhancement of Synechocystis sp. PCC6803 by Heterologous Production of 2-Oxoglutarate:Ferredoxin Oxidoreductase from Chlorobaculum tepidum. Biology (Basel) 2022; 12:biology12010059. [PMID: 36671751 PMCID: PMC9855186 DOI: 10.3390/biology12010059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 12/27/2022] [Accepted: 12/27/2022] [Indexed: 01/01/2023]
Abstract
2-Oxoglutarate:ferredoxin oxidoreductase from Chlorobaculum tepidum (CtOGOR) is a carbon-fixing enzyme in the reductive TCA cycle that reversibly carboxylates succinyl-CoA to yield 2-oxoglutarate. CtOGOR is a heterotetramer of two large (α = 68 kDa) and two small (β = 38 kDa) subunits. The αβ protomer harbors one thiamine pyrophosphate and two 4Fe-4S clusters. Nonetheless, the enzyme has a considerable oxygen tolerance with a half-life of 143 min at 215 μM dissolved oxygen. Kinetic analyses of the purified recombinant CtOGOR revealed a lower Km for succinyl-CoA than for 2-oxoglutarate. Cellular levels of 2-oxoglutarate and glutamate—a product of glutamine oxoglutarate aminotransferase and glutamate dehydrogenase—increased more than twofold in the exponential phase compared with the control strain, leading to an approximately >30% increase in the photoautotrophic growth rate. Thus, CtOGOR was successfully produced in Synechocystis, thereby boosting carboxylation, resulting in enhanced photoautotrophic growth.
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Affiliation(s)
- June Kim
- Department of Life Science, Sogang University, Seoul 121-742, Republic of Korea
| | - Eun Kyoung Oh
- Department of Life Science, Sogang University, Seoul 121-742, Republic of Korea
| | - Eui-Jin Kim
- Microbial Research Department, Nakdonggang National Institute of Biological Resources, Sangju 37242, Republic of Korea
- Correspondence: (E.-J.K.); (J.K.L.); Tel.: +82-54-530-0860 (E.-J.K.); +82-2-705-8459 (J.K.L.); Fax: +82-54-530-0869 (E.-J.K.); +82-2-704-3601 (J.K.L.)
| | - Jeong K. Lee
- Department of Life Science, Sogang University, Seoul 121-742, Republic of Korea
- Correspondence: (E.-J.K.); (J.K.L.); Tel.: +82-54-530-0860 (E.-J.K.); +82-2-705-8459 (J.K.L.); Fax: +82-54-530-0869 (E.-J.K.); +82-2-704-3601 (J.K.L.)
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Zhang GF, Jensen MV, Gray SM, El K, Wang Y, Lu D, Becker TC, Campbell JE, Newgard CB. Reductive TCA cycle metabolism fuels glutamine- and glucose-stimulated insulin secretion. Cell Metab 2021; 33:804-817.e5. [PMID: 33321098 PMCID: PMC8115731 DOI: 10.1016/j.cmet.2020.11.020] [Citation(s) in RCA: 66] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 11/06/2020] [Accepted: 11/25/2020] [Indexed: 12/11/2022]
Abstract
Metabolic fuels regulate insulin secretion by generating second messengers that drive insulin granule exocytosis, but the biochemical pathways involved are incompletely understood. Here we demonstrate that stimulation of rat insulinoma cells or primary rat islets with glucose or glutamine + 2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid (Gln + BCH) induces reductive, "counter-clockwise" tricarboxylic acid (TCA) cycle flux of glutamine to citrate. Molecular or pharmacologic suppression of isocitrate dehydrogenase-2 (IDH2), which catalyzes reductive carboxylation of 2-ketoglutarate to isocitrate, results in impairment of glucose- and Gln + BCH-stimulated reductive TCA cycle flux, lowering of NADPH levels, and inhibition of insulin secretion. Pharmacologic suppression of IDH2 also inhibits insulin secretion in living mice. Reductive TCA cycle flux has been proposed as a mechanism for generation of biomass in cancer cells. Here we demonstrate that reductive TCA cycle flux also produces stimulus-secretion coupling factors that regulate insulin secretion, including in non-dividing cells.
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Affiliation(s)
- Guo-Fang Zhang
- Sarah W. Stedman Nutrition and Metabolism Center and Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27701, USA; Department of Medicine, Endocrinology and Metabolism Division, Duke University Medical Center, Durham, NC 27701, USA
| | - Mette V Jensen
- Sarah W. Stedman Nutrition and Metabolism Center and Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27701, USA
| | - Sarah M Gray
- Sarah W. Stedman Nutrition and Metabolism Center and Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27701, USA
| | - Kimberley El
- Sarah W. Stedman Nutrition and Metabolism Center and Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27701, USA
| | - You Wang
- Sarah W. Stedman Nutrition and Metabolism Center and Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27701, USA
| | - Danhong Lu
- Sarah W. Stedman Nutrition and Metabolism Center and Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27701, USA
| | - Thomas C Becker
- Sarah W. Stedman Nutrition and Metabolism Center and Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27701, USA; Department of Medicine, Endocrinology and Metabolism Division, Duke University Medical Center, Durham, NC 27701, USA
| | - Jonathan E Campbell
- Sarah W. Stedman Nutrition and Metabolism Center and Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27701, USA; Department of Medicine, Endocrinology and Metabolism Division, Duke University Medical Center, Durham, NC 27701, USA; Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27701, USA
| | - Christopher B Newgard
- Sarah W. Stedman Nutrition and Metabolism Center and Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27701, USA; Department of Medicine, Endocrinology and Metabolism Division, Duke University Medical Center, Durham, NC 27701, USA; Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27701, USA.
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