The Entner–Doudoroff pathway is an overlooked glycolytic route in cyanobacteria and plants.

Chen, X., Schreiber, K., Appel, J., Makowka, A., Fahnrich, B., Roettger, M., Hajirezaei, M. R., Sönnichsen, Frank, Schonheit, P., Martin, W. F. and Gutekunst, Kirsten (2016) The Entner–Doudoroff pathway is an overlooked glycolytic route in cyanobacteria and plants. PNAS Proceedings of the National Academy of Sciences of the United States of America, 113 (19). pp. 5441-5446. DOI 10.1073/pnas.1521916113.

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Supplementary data:

Abstract

Glucose degradation pathways are central for energy and carbon metabolism throughout all domains of life. They provide ATP, NAD(P)H, and biosynthetic precursors for amino acids, nucleotides, and fatty acids. It is general knowledge that cyanobacteria and plants oxidize carbohydrates via glycolysis [the Embden-Meyerhof-Parnas (EMP) pathway] and the oxidative pentose phosphate (OPP) pathway. However, we found that both possess a third, previously overlooked pathway of glucose breakdown: the Entner-Doudoroff (ED) pathway. Its key enzyme, 2-keto-3-deoxygluconate-6-phosphate (KDPG) aldolase, is widespread in cyanobacteria, moss, fern, algae, and plants and is even more common among cyanobacteria than phosphofructokinase (PFK), the key enzyme of the EMP pathway. Active KDPG aldolases from the cyanobacterium Synechocystis and the plant barley (Hordeum vulgare) were biochemically characterized in vitro. KDPG, a metabolite unique to the ED pathway, was detected in both in vivo, indicating an active ED pathway. Phylogenetic analyses revealed that photosynthetic eukaryotes acquired KDPG aldolase from the cyanobacterial ancestors of plastids via endosymbiotic gene transfer. Several Synechocystis mutants in which key enzymes of all three glucose degradation pathways were knocked out indicate that the ED pathway is physiologically significant, especially under mixotrophic conditions (light and glucose) and under autotrophic conditions in a day/night cycle, which is probably the most common condition encountered in nature. The ED pathway has lower protein costs and ATP yields than the EMP pathway, in line with the observation that oxygenic photosynthesizers are nutrient-limited, rather than ATP-limited. Furthermore, the ED pathway does not generate futile cycles in organisms that fix CO2 via the Calvin-Benson cycle.

Document Type: Article
Additional Information: Times Cited: 4 Chen, Xi Schreiber, Karoline Appel, Jens Makowka, Alexander Faehnrich, Berit Roettger, Mayo Hajirezaei, Mohammad R. Soennichsen, Frank D. Schoenheit, Peter Martin, William F. Gutekunst, Kirstin
Keywords: glucose degradationEntner–Doudoroff-pathwayEmbden–Meyerhof–Parnas pathwayoxidative pentose phosphate pathwayendosymbiotic gene transfer
Research affiliation: Kiel University > Kiel Marine Science
OceanRep > The Future Ocean - Cluster of Excellence
Kiel University
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1073/pnas.1521916113
ISSN: 0027-8424
Projects: Future Ocean
Date Deposited: 27 Feb 2017 09:27
Last Modified: 20 May 2019 13:05
URI: http://oceanrep.geomar.de/id/eprint/36035

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