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Tabata H, Chikatani G, Nishijima H, Harada T, Miyake R, Kato S, Igarashi K, Mukouyama Y, Shirai S, Waki M, Hase Y, Nakanishi S. Construction of an autocatalytic reaction cycle in neutral medium for synthesis of life-sustaining sugars. Chem Sci 2023; 14:13475-13484. [PMID: 38033894 PMCID: PMC10685314 DOI: 10.1039/d3sc03377e] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Accepted: 10/09/2023] [Indexed: 12/02/2023] Open
Abstract
Autocatalytic mechanisms in carbon metabolism, such as the Calvin cycle, are responsible for the biological assimilation of CO2 to form organic compounds with complex structures, including sugars. Compounds that form C-C bonds with CO2 are regenerated in these autocatalytic reaction cycles, and the products are concurrently released. The formose reaction in basic aqueous solution has attracted attention as a nonbiological reaction involving an autocatalytic reaction cycle that non-enzymatically synthesizes sugars from the C1 compound formaldehyde. However, formaldehyde and sugars, which are the substrate and products of the formose reaction, respectively, are consumed in Cannizzaro reactions, particularly under basic aqueous conditions, which makes the formose reaction a fragile sugar-production system. Here, we constructed an autocatalytic reaction cycle for sugar synthesis under neutral conditions. We focused on the weak Brønsted basicity of oxometalate anions such as tungstates and molybdates as catalysts, thereby enabling the aldol reaction, retro-aldol reaction, and aldose-ketose transformation, which collectively constitute the autocatalytic reaction cycle. These bases acted on sugar molecules of substrates together with sodium ions of a Lewis acid to promote deprotonation under neutral conditions, which is the initiation step of the reactions forming an autocatalytic cycle, whereas the Cannizzaro reaction was inhibited. The autocatalytic reaction cycle established using this abiotic approach is a robust sugar production system. Furthermore, we found that the synthesized sugars work as energy storage substances that sustain microbial growth despite their absence in nature.
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Affiliation(s)
- Hiro Tabata
- Research Center for Solar Energy Chemistry, Graduate School of Engineering Science, Osaka University Toyonaka Osaka 560-8531 Japan
| | - Genta Chikatani
- Research Center for Solar Energy Chemistry, Graduate School of Engineering Science, Osaka University Toyonaka Osaka 560-8531 Japan
| | - Hiroaki Nishijima
- Research Center for Solar Energy Chemistry, Graduate School of Engineering Science, Osaka University Toyonaka Osaka 560-8531 Japan
| | - Takashi Harada
- Research Center for Solar Energy Chemistry, Graduate School of Engineering Science, Osaka University Toyonaka Osaka 560-8531 Japan
| | - Rika Miyake
- Research Center for Solar Energy Chemistry, Graduate School of Engineering Science, Osaka University Toyonaka Osaka 560-8531 Japan
| | - Souichiro Kato
- Research Center for Solar Energy Chemistry, Graduate School of Engineering Science, Osaka University Toyonaka Osaka 560-8531 Japan
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST) 2-17-2-1, Tsukisamu higashi, Toyohira Sapporo 062-8517 Japan
| | - Kensuke Igarashi
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST) 2-17-2-1, Tsukisamu higashi, Toyohira Sapporo 062-8517 Japan
| | - Yoshiharu Mukouyama
- Research Center for Solar Energy Chemistry, Graduate School of Engineering Science, Osaka University Toyonaka Osaka 560-8531 Japan
- Division of Science, College of Science and Engineering, Tokyo Denki University Hatoyama Saitama 350-0394 Japan
| | - Soichi Shirai
- Toyota Central R&D Labs., Inc. 41-1 Yokomichi Nagakute Aichi 480-1192 Japan
| | - Minoru Waki
- Toyota Central R&D Labs., Inc. 41-1 Yokomichi Nagakute Aichi 480-1192 Japan
| | - Yoko Hase
- Research Center for Solar Energy Chemistry, Graduate School of Engineering Science, Osaka University Toyonaka Osaka 560-8531 Japan
- Toyota Central R&D Labs., Inc. 41-1 Yokomichi Nagakute Aichi 480-1192 Japan
| | - Shuji Nakanishi
- Research Center for Solar Energy Chemistry, Graduate School of Engineering Science, Osaka University Toyonaka Osaka 560-8531 Japan
- Innovative Catalysis Science Division, Institute for Open and Transdisciplinary Research Initiatives (ICS-OTRI), Osaka University Suita Osaka 565-0871 Japan
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