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Yun EJ, Yu S, Kim DH, Park NJ, Liu JJ, Jin YS, Kim KH. Identification of the enantiomeric nature of 2-keto-3-deoxy-galactonate in the catabolic pathway of 3,6-anhydro-L-galactose. Appl Microbiol Biotechnol 2023; 107:7427-7438. [PMID: 37812254 DOI: 10.1007/s00253-023-12807-7] [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: 04/07/2023] [Revised: 07/28/2023] [Accepted: 09/19/2023] [Indexed: 10/10/2023]
Abstract
A novel metabolic pathway of 3,6-anhydro-L-galactose (L-AHG), the main sugar component in red macroalgae, was first discovered in the marine bacterium Vibrio sp. EJY3. L-AHG is converted to 2-keto-3-deoxy-galactonate (KDGal) in two metabolic steps. Here, we identified the enantiomeric nature of KDGal in the L-AHG catabolic pathway via stereospecific enzymatic reactions accompanying the biosynthesis of enantiopure L-KDGal and D-KDGal. Enantiopure L-KDGal and D-KDGal were synthesized by enzymatic reactions derived from the fungal galacturonate and bacterial oxidative galactose pathways, respectively. KDGal, which is involved in the L-AHG pathway, was also prepared. The results obtained from the reactions with an L-KDGal aldolase, specifically acting on L-KDGal, showed that KDGal in the L-AHG pathway exists in an L-enantiomeric form. Notably, we demonstrated the utilization of L-KDGal by Escherichia coli for the first time. E. coli cannot utilize L-KDGal as the sole carbon source. However, when a mixture of L-KDGal and D-galacturonate was used, E. coli utilized both. Our study suggests a stereoselective method to determine the absolute configuration of a compound. In addition, our results can be used to explore the novel L-KDGal catabolic pathway in E. coli and to construct an engineered microbial platform that assimilates L-AHG or L-KDGal as substrates. KEY POINTS: • Stereospecific enzyme reactions were used to identify enantiomeric nature of KDGal • KDGal in the L-AHG catabolic pathway exists in an L-enantiomeric form • E. coli can utilize L-KDGal as a carbon source when supplied with D-galacturonate.
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Affiliation(s)
- Eun Ju Yun
- Department of Biotechnology, Graduate School, College of Life Sciences and Biotechnology, Korea University, Seoul, 02841, Republic of Korea
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
- Division of Biotechnology, College of Environmental and Bioresource Sciences, Jeonbuk National University, Iksan, 54596, Republic of Korea
| | - Sora Yu
- Department of Biotechnology, Graduate School, College of Life Sciences and Biotechnology, Korea University, Seoul, 02841, Republic of Korea
| | - Dong Hyun Kim
- Department of Biotechnology, Graduate School, College of Life Sciences and Biotechnology, Korea University, Seoul, 02841, Republic of Korea
- School of Food Science and Biotechnology, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Na Jung Park
- Department of Biotechnology, Graduate School, College of Life Sciences and Biotechnology, Korea University, Seoul, 02841, Republic of Korea
| | - Jing-Jing Liu
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Yong-Su Jin
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
| | - Kyoung Heon Kim
- Department of Biotechnology, Graduate School, College of Life Sciences and Biotechnology, Korea University, Seoul, 02841, Republic of Korea.
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Tsevelkhorloo M, Kim SH, Kang DK, Lee CR, Hong SK. NADP +-Dependent Dehydrogenase SCO3486 and Cycloisomerase SCO3480: Key Enzymes for 3,6-Anhydro-L-Galactose Catabolism in Streptomyces coelicolor A3(2). J Microbiol Biotechnol 2021; 31:756-763. [PMID: 33820885 PMCID: PMC9706016 DOI: 10.4014/jmb.2103.03030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 03/30/2021] [Accepted: 04/05/2021] [Indexed: 12/15/2022]
Abstract
Agarose is a linear polysaccharide composed of D-galactose and 3,6-anhydro-L-galactose (AHG). It is a major component of the red algal cell wall and is gaining attention as an abundant marine biomass. However, the inability to ferment AHG is considered an obstacle in the large-scale use of agarose and could be addressed by understanding AHG catabolism in agarolytic microorganisms. Since AHG catabolism was uniquely confirmed in Vibrio sp. EJY3, a gram-negative marine bacterial species, we investigated AHG metabolism in Streptomyces coelicolor A3(2), an agarolytic gram-positive soil bacterium. Based on genomic data, the SCO3486 protein (492 amino acids) and the SCO3480 protein (361 amino acids) of S. coelicolor A3(2) showed identity with H2IFE7.1 (40% identity) encoding AHG dehydrogenase and H2IFX0.1 (42% identity) encoding 3,6-anhydro-L-galactonate cycloisomerase, respectively, which are involved in the initial catabolism of AHG in Vibrio sp. EJY3. Thin layer chromatography and mass spectrometry of the bioconversion products catalyzed by recombinant SCO3486 and SCO3480 proteins, revealed that SCO3486 is an AHG dehydrogenase that oxidizes AHG to 3,6-anhydro-L-galactonate, and SCO3480 is a 3,6-anhydro-L-galactonate cycloisomerase that converts 3,6-anhydro-L-galactonate to 2-keto-3-deoxygalactonate. SCO3486 showed maximum activity at pH 6.0 at 50°C, increased activity in the presence of iron ions, and activity against various aldehyde substrates, which is quite distinct from AHG-specific H2IFE7.1 in Vibrio sp. EJY3. Therefore, the catabolic pathway of AHG seems to be similar in most agar-degrading microorganisms, but the enzymes involved appear to be very diverse.
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Affiliation(s)
- Maral Tsevelkhorloo
- Department of Biosciences and Bioinformatics, Myongji University, Yongin 17058, Republic of Korea
| | - Sang Hoon Kim
- Department of Animal Resources Science, Dankook University, Cheonan 31116, Republic of Korea
| | - Dae-Kyung Kang
- Department of Animal Resources Science, Dankook University, Cheonan 31116, Republic of Korea
| | - Chang-Ro Lee
- Department of Biosciences and Bioinformatics, Myongji University, Yongin 17058, Republic of Korea
| | - Soon-Kwang Hong
- Department of Biosciences and Bioinformatics, Myongji University, Yongin 17058, Republic of Korea,Corresponding author Phone: 82-31-330-6198 Fax: 82-31-335-8249 E-mail:
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Trincone A. Application-Oriented Marine Isomerases in Biocatalysis. Mar Drugs 2020; 18:md18110580. [PMID: 33233366 PMCID: PMC7700177 DOI: 10.3390/md18110580] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 11/16/2020] [Accepted: 11/20/2020] [Indexed: 12/23/2022] Open
Abstract
The class EC 5.xx, a group of enzymes that interconvert optical, geometric, or positional isomers are interesting biocatalysts for the synthesis of pharmaceuticals and pharmaceutical intermediates. This class, named “isomerases,” can transform cheap biomolecules into expensive isomers with suitable stereochemistry useful in synthetic medicinal chemistry, and interesting cases of production of l-ribose, d-psicose, lactulose, and d-phenylalanine are known. However, in two published reports about potential biocatalysts of marine origin, isomerases are hardly mentioned. Therefore, it is of interest to deepen the knowledge of these biocatalysts from the marine environment with this specialized in-depth analysis conducted using a literature search without time limit constraints. In this review, the focus is dedicated mainly to example applications in biocatalysis that are not numerous confirming the general view previously reported. However, from this overall literature analysis, curiosity-driven scientific interest for marine isomerases seems to have been long-standing. However, the major fields in which application examples are framed are placed at the cutting edge of current biotechnological development. Since these enzymes can offer properties of industrial interest, this will act as a promoter for future studies of marine-originating isomerases in applied biocatalysis.
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Affiliation(s)
- Antonio Trincone
- Institute of Biomolecular Chemistry, National Research Council, Via Campi Flegrei, 34, 80078 Pozzuoli, Italy
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