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Katane M, Homma H. Biosynthesis and Degradation of Free D-Amino Acids and Their Physiological Roles in the Periphery and Endocrine Glands. Biol Pharm Bull 2024; 47:562-579. [PMID: 38432912 DOI: 10.1248/bpb.b23-00485] [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] [Indexed: 03/05/2024]
Abstract
It was long believed that D-amino acids were either unnatural isomers or laboratory artifacts, and that the important functions of amino acids were exerted only by L-amino acids. However, recent investigations have revealed a variety of D-amino acids in mammals that play important roles in physiological functions, including free D-serine and D-aspartate that are crucial in the central nervous system. The functions of several D-amino acids in the periphery and endocrine glands are also receiving increasing attention. Here, we present an overview of recent advances in elucidating the physiological roles of D-amino acids, especially in the periphery and endocrine glands.
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Affiliation(s)
- Masumi Katane
- Medicinal Research Laboratories, Graduate School of Pharmaceutical Sciences, Kitasato University
| | - Hiroshi Homma
- Laboratory of Analytical Chemistry, Graduate School of Pharmaceutical Sciences, Kitasato University
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2
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Yu Y, Wang P, Cao HY, Teng ZJ, Zhu Y, Wang M, McMinn A, Chen Y, Xiang H, Zhang YZ, Chen XL, Zhang YQ. Novel D-glutamate catabolic pathway in marine Proteobacteria and halophilic archaea. THE ISME JOURNAL 2023; 17:537-548. [PMID: 36690779 PMCID: PMC10030869 DOI: 10.1038/s41396-023-01364-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 01/07/2023] [Accepted: 01/11/2023] [Indexed: 01/25/2023]
Abstract
D-glutamate (D-Glu) is an essential component of bacterial peptidoglycans, representing an important, yet overlooked, pool of organic matter in global oceans. However, little is known on D-Glu catabolism by marine microorganisms. Here, a novel catabolic pathway for D-Glu was identified using the marine bacterium Pseudoalteromonas sp. CF6-2 as the model. Two novel enzymes (DgcN, DgcA), together with a transcriptional regulator DgcR, are crucial for D-Glu catabolism in strain CF6-2. Genetic and biochemical data confirm that DgcN is a N-acetyltransferase which catalyzes the formation of N-acetyl-D-Glu from D-Glu. DgcA is a racemase that converts N-acetyl-D-Glu to N-acetyl-L-Glu, which is further hydrolyzed to L-Glu. DgcR positively regulates the transcription of dgcN and dgcA. Structural and biochemical analyses suggested that DgcN and its homologs, which use D-Glu as the acyl receptor, represent a new group of the general control non-repressible 5 (GCN5)-related N-acetyltransferases (GNAT) superfamily. DgcA and DgcN occur widely in marine bacteria (particularly Rhodobacterales) and halophilic archaea (Halobacteria) and are abundant in marine and hypersaline metagenome datasets. Thus, this study reveals a novel D-Glu catabolic pathway in ecologically important marine bacteria and halophilic archaea and helps better understand the catabolism and recycling of D-Glu in these ecosystems.
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Affiliation(s)
- Yang Yu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Peng Wang
- College of Marine Life Sciences & Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
| | - Hai-Yan Cao
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Zhao-Jie Teng
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Yanping Zhu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Min Wang
- College of Marine Life Sciences & Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
| | - Andrew McMinn
- College of Marine Life Sciences & Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, TAS, Australia
| | - Yin Chen
- College of Marine Life Sciences & Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
- School of Life Sciences, University of Warwick, Coventry, UK
| | - Hua Xiang
- University of Chinese Academy of Sciences, Beijing, China
- State Key Laboratory of Microbial Resources, the Institute of Microbiology CAS, Beijing, China
| | - Yu-Zhong Zhang
- College of Marine Life Sciences & Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China.
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China.
- Marine Biotechnology Research Center, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China.
| | - Xiu-Lan Chen
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China.
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China.
| | - Yu-Qiang Zhang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China.
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Yu Y, Yang J, Teng ZJ, Zheng LY, Sheng Q, Li PY, Fu HH, Li CY, Chen Y, Zhang YZ, Ding JM, Chen XL. d-Alanine Metabolism via d-Ala Aminotransferase by a Marine Gammaproteobacterium, Pseudoalteromonas sp. Strain CF6-2. Appl Environ Microbiol 2022; 88:e0221921. [PMID: 34818098 PMCID: PMC8824272 DOI: 10.1128/aem.02219-21] [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: 11/09/2021] [Accepted: 11/12/2021] [Indexed: 11/20/2022] Open
Abstract
As the most abundant d-amino acid (DAA) in the ocean, d-alanine (d-Ala) is a key component of peptidoglycan in the bacterial cell wall. However, the underlying mechanisms of bacterial metabolization of d-Ala through the microbial food web remain largely unknown. In this study, the metabolism of d-Ala by marine bacterium Pseudoalteromonas sp. strain CF6-2 was investigated. Based on genomic, transcriptional, and biochemical analyses combined with gene knockout, d-Ala aminotransferase was found to be indispensable for the catabolism of d-Ala in strain CF6-2. Investigation on other marine bacteria also showed that d-Ala aminotransferase gene is a reliable indicator for their ability to utilize d-Ala. Bioinformatic investigation revealed that d-Ala aminotransferase sequences are prevalent in genomes of marine bacteria and metagenomes, especially in seawater samples, and Gammaproteobacteria represents the predominant group containing d-Ala aminotransferase. Thus, Gammaproteobacteria is likely the dominant group to utilize d-Ala via d-Ala aminotransferase to drive the recycling and mineralization of d-Ala in the ocean. IMPORTANCE As the most abundant d-amino acid in the ocean, d-Ala is a component of the marine DON (dissolved organic nitrogen) pool. However, the underlying mechanism of bacterial metabolization of d-Ala to drive the recycling and mineralization of d-Ala in the ocean is still largely unknown. The results in this study showed that d-Ala aminotransferase is specific and indispensable for d-Ala catabolism in marine bacteria and that marine bacteria containing d-Ala aminotransferase genes are predominantly Gammaproteobacteria widely distributed in global oceans. This study reveals marine d-Ala-utilizing bacteria and the mechanism of their metabolization of d-Ala. The results shed light on the mechanisms of recycling and mineralization of d-Ala driven by bacteria in the ocean, which are helpful in understanding oceanic microbial-mediated nitrogen cycle.
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Affiliation(s)
- Yang Yu
- State Key Laboratory of Microbial Technology and Marine Biotechnology Research Center, Shandong University, Qingdao, China
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
| | - Jie Yang
- State Key Laboratory of Microbial Technology and Marine Biotechnology Research Center, Shandong University, Qingdao, China
- College of Food Science and Engineering, Qingdao Agricultural University, Qingdao, China
| | - Zhao-Jie Teng
- State Key Laboratory of Microbial Technology and Marine Biotechnology Research Center, Shandong University, Qingdao, China
| | - Li-Yuan Zheng
- State Key Laboratory of Microbial Technology and Marine Biotechnology Research Center, Shandong University, Qingdao, China
| | - Qi Sheng
- State Key Laboratory of Microbial Technology and Marine Biotechnology Research Center, Shandong University, Qingdao, China
| | - Ping-Yi Li
- State Key Laboratory of Microbial Technology and Marine Biotechnology Research Center, Shandong University, Qingdao, China
| | - Hui-Hui Fu
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
| | - Chun-Yang Li
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
| | - Yin Chen
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Yu-Zhong Zhang
- State Key Laboratory of Microbial Technology and Marine Biotechnology Research Center, Shandong University, Qingdao, China
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
| | - Jun-Mei Ding
- Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Yunnan Normal University, Kunming, China
| | - Xiu-Lan Chen
- State Key Laboratory of Microbial Technology and Marine Biotechnology Research Center, Shandong University, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
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Ashida H, Murakami K, Inagaki K, Sawa Y, Hemmi H, Iwasaki Y, Yoshimura T. Evolution and properties of alanine racemase from Synechocystis sp. PCC6803. J Biochem 2021; 171:421-428. [PMID: 34967408 DOI: 10.1093/jb/mvab155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 12/20/2021] [Indexed: 11/14/2022] Open
Abstract
Alanine racemase (EC 5.1.1.1) depends on pyridoxal 5'-phosphate and catalyzes the interconversion between L- and D-Ala. The enzyme is responsible for the biosynthesis of D-Ala, which is an essential component of the peptidoglycan layer of bacterial cell walls. Phylogenetic analysis of alanine racemases demonstrated that the cyanobacterial enzyme diverged before the separation of gram-positive and gram-negative enzymes. This result is interesting considering that the peptidoglycans observed in cyanobacteria seem to combine the properties of those in both gram-negative and gram-positive bacteria. We cloned the putative alanine racemase gene (slr0823) of Synechocystis sp. PCC6803 in E. coli cells, expressed and purified the enzyme protein, and studied its enzymological properties. The enzymatic properties of the Synechocystis enzyme were similar to those of other gram-positive and gram-negative bacterial enzymes. Alignment of the amino acid sequences of alanine racemase enzymes revealed that the conserved tyrosine residue in the active center of most of the gram-positive and gram-negative bacterial enzymes has been replaced with tryptophan in most of the cyanobacterial enzymes. We carried out the site-directed mutagenesis involving the corresponding residue of Synechocystis enzyme (W385), and revealed that the residue is involved in the substrate recognition by the enzyme.
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Affiliation(s)
- Hiroyuki Ashida
- Department of Molecular and Functional Genomics, Interdisciplinary Center for Science Research, Shimane University
| | - Kaho Murakami
- Department of Biofunctional Chemistry, Graduate School of Environmental and Life Science, Okayama University
| | - Kenji Inagaki
- Department of Biofunctional Chemistry, Graduate School of Environmental and Life Science, Okayama University
| | - Yoshihiro Sawa
- Department of Life Science and Biotechnology, Faculty of Life and Environmental Science, Shimane University
| | - Hisashi Hemmi
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University
| | - Yugo Iwasaki
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University
| | - Tohru Yoshimura
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University
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5
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Wątły J, Miller A, Kozłowski H, Rowińska-Żyrek M. Peptidomimetics - An infinite reservoir of metal binding motifs in metabolically stable and biologically active molecules. J Inorg Biochem 2021; 217:111386. [PMID: 33610030 DOI: 10.1016/j.jinorgbio.2021.111386] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Revised: 01/14/2021] [Accepted: 01/27/2021] [Indexed: 12/12/2022]
Abstract
The involvement of metal ions in interactions with therapeutic peptides is inevitable. They are one of the factors able to fine-tune the biological properties of antimicrobial peptides, a promising group of drugs with one large drawback - a problematic metabolic stability. Appropriately chosen, proteolytically stable peptidomimetics seem to be a reasonable solution of the problem, and the use of D-, β-, γ-amino acids, unnatural amino acids, azapeptides, peptoids, cyclopeptides and dehydropeptides is an infinite reservoir of metal binding motifs in metabolically stable, well-designed, biologically active molecules. Below, their specific structural features, metal-chelating abilities and antimicrobial potential are discussed.
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Affiliation(s)
- Joanna Wątły
- Faculty of Chemistry, University of Wroclaw, Joliot - Curie 14, Wroclaw 50-383, Poland.
| | - Adriana Miller
- Faculty of Chemistry, University of Wroclaw, Joliot - Curie 14, Wroclaw 50-383, Poland
| | - Henryk Kozłowski
- Faculty of Chemistry, University of Wroclaw, Joliot - Curie 14, Wroclaw 50-383, Poland; Department of Health Sciences, University of Opole, Katowicka 68, Opole 45-060, Poland
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Yu Y, Yang J, Zheng LY, Sheng Q, Li CY, Wang M, Zhang XY, McMinn A, Zhang YZ, Song XY, Chen XL. Diversity of D-Amino Acid Utilizing Bacteria From Kongsfjorden, Arctic and the Metabolic Pathways for Seven D-Amino Acids. Front Microbiol 2020; 10:2983. [PMID: 31998270 PMCID: PMC6965332 DOI: 10.3389/fmicb.2019.02983] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 12/10/2019] [Indexed: 12/20/2022] Open
Abstract
D-amino acids (DAAs) are an important component of the refractory dissolved organic matter pool in the ocean. Microbes play a vital role in promoting the recycling of DAAs in the ocean. However, the diversity of marine DAA-utilizing bacteria and how they metabolize DAAs are seldom studied. Here, by enrichment culture with DAAs as the sole nitrogen source, bacteria of 12 families from three phyla were recovered from surface seawater and sediment from Kongsfjorden, Arctic, and seven DAA-utilizing bacterial strains were isolated. These strains have different DAA-utilizing abilities. Of the seven DAAs used, Halomonas titanicae SM1922 and Pseudoalteromonas neustonica SM1927 were able to utilize seven and five of them, respectively, while the other strains were able to utilize only one or two. Based on genomic, transcriptional and biochemical analyses, the key genes involved in DAA metabolism in each strain were identified and the metabolic pathways for the seven DAAs in these marine bacteria were identified. Conversion of DAAs into α-keto acids is generally the main pathway in marine DAA-utilizing bacteria, which is performed by several key enzymes, including DAA oxidoreductases/dehydrogenases, D-serine ammonia-lyases, D-serine ammonia-lyase DSD1s and DAA transaminases. In addition, conversion of DAAs into LAAs is another pathway, which is performed by amino acid racemases. Among the identified key enzymes, D-serine ammonia-lyase DSD1 and Asp racemase are first found to be employed by bacteria for DAA utilization. These results shed light on marine DAA-utilizing bacteria and the involved DAA metabolism pathways, offering a better understanding of the DAA recycling in the ocean.
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Affiliation(s)
- Yang Yu
- State Key Laboratory of Microbial Technology, Institute of Marine Science and Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China
| | - Jie Yang
- State Key Laboratory of Microbial Technology, Institute of Marine Science and Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China
| | - Li-Yuan Zheng
- State Key Laboratory of Microbial Technology, Institute of Marine Science and Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China
| | - Qi Sheng
- State Key Laboratory of Microbial Technology, Institute of Marine Science and Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China
| | - Chun-Yang Li
- College of Marine Life Sciences, Institute for Advanced Ocean Study, Ocean University of China, Qingdao, China
| | - Min Wang
- College of Marine Life Sciences, Institute for Advanced Ocean Study, Ocean University of China, Qingdao, China
| | - Xi-Ying Zhang
- State Key Laboratory of Microbial Technology, Institute of Marine Science and Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China
| | - Andrew McMinn
- College of Marine Life Sciences, Institute for Advanced Ocean Study, Ocean University of China, Qingdao, China.,Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, TAS, Australia
| | - Yu-Zhong Zhang
- State Key Laboratory of Microbial Technology, Institute of Marine Science and Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China.,College of Marine Life Sciences, Institute for Advanced Ocean Study, Ocean University of China, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
| | - Xiao-Yan Song
- State Key Laboratory of Microbial Technology, Institute of Marine Science and Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China
| | - Xiu-Lan Chen
- State Key Laboratory of Microbial Technology, Institute of Marine Science and Technology, Marine Biotechnology Research Center, Shandong University, Qingdao, China
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7
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Uda K, Edashige Y, Nishimura R, Shikano Y, Matsui T, Radkov AD, Moe LA. Distribution and evolution of the serine/aspartate racemase family in plants. PHYTOCHEMISTRY 2020; 169:112164. [PMID: 31622858 DOI: 10.1016/j.phytochem.2019.112164] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 09/24/2019] [Accepted: 10/02/2019] [Indexed: 06/10/2023]
Abstract
Previous studies have shown that several d-amino acids are widely present in plants, and serine racemase (SerR), which synthesizes d-serine in vivo, has already been identified from three plant species. However, the full picture of the d-amino acid synthesis pathway in plants is not well understood. To clarify the distribution of amino acid racemases in plants, we have cloned, expressed and characterized eight SerR homologous genes from five plant species, including green alga. These SerR homologs exhibited racemase activity towards serine or aspartate and were identified on the basis of their maximum activity as SerR or aspartate racemase (AspR). The plant AspR gene is identified for the first time from Medicago truncatula, Manihot esculenta, Solanum lycopersicum, Sphagnum girgensohnii and Spirogyra pratensis. In addition to the AspR gene, three SerR genes are identified in the former three species. Phylogenetic tree analysis showed that SerR and AspR are widely distributed in plants and form a serine/aspartate racemase family cluster. The catalytic efficiency (kcat/Km) of plant AspRs was more than 100 times higher than that of plant SerRs, suggesting that d-aspartate, as well as d-serine, can be synthesized in vivo by AspR. The amino acid sequence alignment and comparison of the chromosomal gene arrangement have revealed that plant AspR genes independently evolved from SerR in each ancestral lineage of plant species by gene duplication and acquisition of two serine residues at position 150 to 152.
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Affiliation(s)
- Kouji Uda
- Laboratory of Biochemistry, Faculty of Science and Technology, Kochi University, Kochi, 780-8520, Japan.
| | - Yumika Edashige
- Laboratory of Biochemistry, Faculty of Science and Technology, Kochi University, Kochi, 780-8520, Japan
| | - Rie Nishimura
- Laboratory of Biochemistry, Faculty of Science and Technology, Kochi University, Kochi, 780-8520, Japan
| | - Yuuna Shikano
- Laboratory of Biochemistry, Faculty of Science and Technology, Kochi University, Kochi, 780-8520, Japan
| | - Tohru Matsui
- Laboratory of Plant Taxonomy, Faculty of Science and Technology, Kochi University, Kochi, 780-8520, Japan
| | - Atanas D Radkov
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA, 94158, USA
| | - Luke A Moe
- Department of Plant and Soil Sciences, 311 Plant Science Building, University of Kentucky, Lexington, KY, 40546-0312, USA
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Rybak MY, Rayevsky AV, Gudzera OI, Tukalo MA. Stereospecificity control in aminoacyl-tRNA-synthetases: new evidence of d-amino acids activation and editing. Nucleic Acids Res 2019; 47:9777-9788. [PMID: 31504788 PMCID: PMC6765224 DOI: 10.1093/nar/gkz756] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Revised: 08/14/2019] [Accepted: 08/21/2019] [Indexed: 02/02/2023] Open
Abstract
The homochirality of amino acids is vital for the functioning of the translation apparatus. l-Amino acids predominate in proteins and d-amino acids usually represent diverse regulatory functional physiological roles in both pro- and eukaryotes. Aminoacyl-tRNA-synthetases (aaRSs) ensure activation of proteinogenic or nonproteinogenic amino acids and attach them to cognate or noncognate tRNAs. Although many editing mechanisms by aaRSs have been described, data about the protective role of aaRSs in d-amino acids incorporation remained unknown. Tyrosyl- and alanyl-tRNA-synthetases were represented as distinct members of this enzyme family. To study the potential to bind and edit noncognate substrates, Thermus thermophilus alanyl-tRNA-synthetase (AlaRS) and tyrosyl-tRNA-synthetase were investigated in the context of d-amino acids recognition. Here, we showed that d-alanine was effectively activated by AlaRS and d-Ala-tRNAAla, formed during the erroneous aminoacylation, was edited by AlaRS. On the other hand, it turned out that d-aminoacyl-tRNA-deacylase (DTD), which usually hydrolyzes d-aminoacyl-tRNAs, was inactive against d-Ala-tRNAAla. To support the finding about DTD, computational docking and molecular dynamics simulations were run. Overall, our work illustrates the novel function of the AlaRS editing domain in stereospecificity control during translation together with trans-editing factor DTD. Thus, we propose different evolutionary strategies for the maintenance of chiral selectivity during translation.
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Affiliation(s)
- Mariia Yu Rybak
- Department of Protein Synthesis Enzymology, Institute of Molecular Biology and Genetics of the NAS of Ukraine, 150 Zabolotnogo Street, 03143, Kyiv, Ukraine
| | - Alexey V Rayevsky
- Department of Protein Synthesis Enzymology, Institute of Molecular Biology and Genetics of the NAS of Ukraine, 150 Zabolotnogo Street, 03143, Kyiv, Ukraine
| | - Olga I Gudzera
- Department of Protein Synthesis Enzymology, Institute of Molecular Biology and Genetics of the NAS of Ukraine, 150 Zabolotnogo Street, 03143, Kyiv, Ukraine
| | - Michael A Tukalo
- Department of Protein Synthesis Enzymology, Institute of Molecular Biology and Genetics of the NAS of Ukraine, 150 Zabolotnogo Street, 03143, Kyiv, Ukraine
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9
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Matsumoto N, Kanauchi M. Assaying D-Body Amino Acids as D-Alanine and Amino Acid Racemase (AARase) Activity Using NADH Oxidoreduction Enzymic System. Methods Mol Biol 2019; 1887:23-31. [PMID: 30506246 DOI: 10.1007/978-1-4939-8907-2_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Fermented foods produced using edible microorganisms have been consumed worldwide since ancient times. Microorganisms produce some healthy functional substances. Recently, many people have been attracted to the notion that D-body amino acids have healthy functional effects. D-body amino acids convert L-body amino acid proteolysis from a substrate such as foods during fermentation. This chapter presents a description of methods used for D-alanine assays in the solution as medium and AARase assays in lactic acid bacteria (LAB) cells for isolation of high AARase-containing strains using D-amino acid oxidase and lactic acid dehydrogenase via a NADH oxidoreduction system.
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Affiliation(s)
- Natsuki Matsumoto
- Department of Food Management, Miyagi University, Sendai, Miyagi, Japan
| | - Makoto Kanauchi
- Department of Food Management, Miyagi University, Sendai, Miyagi, Japan.
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10
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Structural features and kinetic characterization of alanine racemase from Bacillus pseudofirmus OF4. Biochem Biophys Res Commun 2018; 497:139-145. [DOI: 10.1016/j.bbrc.2018.02.041] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 02/05/2018] [Indexed: 02/02/2023]
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11
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Duque E, Daddaoua A, Cordero BF, De la Torre J, Antonia Molina-Henares M, Ramos JL. Identification and elucidation of in vivo function of two alanine racemases from Pseudomonas putida KT2440. ENVIRONMENTAL MICROBIOLOGY REPORTS 2017; 9:581-588. [PMID: 28799718 DOI: 10.1111/1758-2229.12576] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 08/03/2017] [Indexed: 06/07/2023]
Abstract
The genome of Pseudomonas putida KT2440 contains two open reading frames (ORFs), PP_3722 and PP_5269, that encode proteins with a Pyridoxal phosphate binding motif and a high similarity to alanine racemases. Alanine racemases play a key role in the biosynthesis of D-alanine, a crucial amino acid in the peptidoglycan layer. For these ORFs, we generated single and double mutants and found that inactivation of PP_5269 resulted in D-alanine auxotrophy, while inactivation of PP_3722 did not. Furthermore, as expected, the PP_3722/PP_5269 double mutant was a strict auxotroph for D-alanine. These results indicate that PP_5269 is an alr allele and that it is the essential alanine racemase in P. putida. We observed that the PP_5269 mutant grew very slowly, while the double PP_5269/PP_3722 mutant did not grow at all. This suggests that PP_3722 may replace PP_5269 in vivo. In fact, when the ORF encoding PP_3772 was cloned into a wide host range expression vector, ORF PP_3722 successfully complemented P. putida PP_5269 mutants. We purified both proteins to homogeneity and while they exhibit similar KM values, the Vmax of PP_5269 is fourfold higher than that of PP_3722. Here, we propose that PP_5269 and PP_3722 encode functional alanine racemases and that these genes be named alr-1 and alr-2 respectively.
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Affiliation(s)
- Estrella Duque
- Department of Environmental Protection, CSIC-Estación Experimental del Zaidín, Granada, Spain
| | - Abdelali Daddaoua
- Department of Environmental Protection, CSIC-Estación Experimental del Zaidín, Granada, Spain
| | - Baldo F Cordero
- Department of Environmental Protection, CSIC-Estación Experimental del Zaidín, Granada, Spain
| | - Jesús De la Torre
- Department of Environmental Protection, CSIC-Estación Experimental del Zaidín, Granada, Spain
| | | | - Juan-Luis Ramos
- Department of Environmental Protection, CSIC-Estación Experimental del Zaidín, Granada, Spain
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12
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Naranjo-Ortíz MA, Brock M, Brunke S, Hube B, Marcet-Houben M, Gabaldón T. Widespread Inter- and Intra-Domain Horizontal Gene Transfer of d-Amino Acid Metabolism Enzymes in Eukaryotes. Front Microbiol 2016; 7:2001. [PMID: 28066338 PMCID: PMC5169069 DOI: 10.3389/fmicb.2016.02001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 11/29/2016] [Indexed: 01/22/2023] Open
Abstract
Analysis of the growing number of available fully-sequenced genomes has shown that Horizontal Gene Transfer (HGT) in eukaryotes is more common than previously thought. It has been proposed that genes with certain functions may be more prone to HGT than others, but we still have a very poor understanding of the selective forces driving eukaryotic HGT. Recent work uncovered that d-amino acid racemases have been commonly transferred from bacteria to fungi, but their role in the receiving organisms is currently unknown. Here, we set out to assess whether d-amino acid racemases are commonly transferred to and between eukaryotic groups. For this we performed a global survey that used a novel automated phylogeny-based HGT-detection algorithm (Abaccus). Our results revealed that at least 7.0% of the total eukaryotic racemase repertoire is the result of inter- or intra-domain HGT. These transfers are significantly enriched in plant-associated fungi. For these, we hypothesize a possible role for the acquired racemases allowing to exploit minoritary nitrogen sources in plant biomass, a nitrogen-poor environment. Finally, we performed experiments on a transferred aspartate-glutamate racemase in the fungal human pathogen Candida glabrata, which however revealed no obvious biological role.
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Affiliation(s)
- Miguel A Naranjo-Ortíz
- Centre for Genomic Regulation, The Barcelona Institute of Science and TechnologyBarcelona, Spain; Universitat Pompeu FabraBarcelona, Spain
| | - Matthias Brock
- Fungal Genetics and Biology Group, School of Life Sciences, University of Nottingham Nottingham, UK
| | - Sascha Brunke
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute Jena Jena, Germany
| | - Bernhard Hube
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute JenaJena, Germany; Friedrich Schiller UniversityJena, Germany; Center for Sepsis Control and Care, University HospitalJena, Germany
| | - Marina Marcet-Houben
- Centre for Genomic Regulation, The Barcelona Institute of Science and TechnologyBarcelona, Spain; Universitat Pompeu FabraBarcelona, Spain
| | - Toni Gabaldón
- Centre for Genomic Regulation, The Barcelona Institute of Science and TechnologyBarcelona, Spain; Universitat Pompeu FabraBarcelona, Spain; Institució Catalana de Recerca i Estudis Avançats (ICREA)Barcelona, Spain
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13
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Hernández SB, Cava F. Environmental roles of microbial amino acid racemases. Environ Microbiol 2015; 18:1673-85. [DOI: 10.1111/1462-2920.13072] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 09/15/2015] [Accepted: 09/27/2015] [Indexed: 02/02/2023]
Affiliation(s)
- Sara B. Hernández
- Laboratory for Molecular Infection Medicine Sweden; Department of Molecular Biology; Umeå Centre for Microbial Research; Umeå University; 90187 Umeå Sweden
| | - Felipe Cava
- Laboratory for Molecular Infection Medicine Sweden; Department of Molecular Biology; Umeå Centre for Microbial Research; Umeå University; 90187 Umeå Sweden
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Liu Y, Koh CMJ, Ngoh ST, Ji L. Engineering an efficient and tight D-amino acid-inducible gene expression system in Rhodosporidium/Rhodotorula species. Microb Cell Fact 2015; 14:170. [PMID: 26502730 PMCID: PMC4624585 DOI: 10.1186/s12934-015-0357-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 10/07/2015] [Indexed: 12/05/2022] Open
Abstract
Background Rhodosporidium and Rhodotorula are two genera of oleaginous red yeast with great potential for industrial biotechnology. To date, there is no effective method for inducible expression of proteins and RNAs in these hosts. Results We have developed a luciferase gene reporter assay based on a new codon-optimized LUC2 reporter gene (RtLUC2), which is flanked with CAR2 homology arms and can be integrated into the CAR2 locus in the nuclear genome at >90 % efficiency. We characterized the upstream DNA sequence of a d-amino acid oxidase gene (DAO1) from R. toruloides ATCC 10657 by nested deletions. By comparing the upstream DNA sequences of several putative DAO1 homologs of Basidiomycetous fungi, we identified a conserved DNA motif with a consensus sequence of AGGXXGXAGX11GAXGAXGG within a 0.2 kb region from the mRNA translation initiation site. Deletion of this motif led to strong mRNA transcription under non-inducing conditions. Interestingly, DAO1 promoter activity was enhanced about fivefold when the 108 bp intron 1 was included in the reporter construct. We identified a conserved CT-rich motif in the intron with a consensus sequence of TYTCCCYCTCCYCCCCACWYCCGA, deletion or point mutations of which drastically reduced promoter strength under both inducing and non-inducing conditions. Additionally, we created a selection marker-free DAO1-null mutant (∆dao1e) which displayed greatly improved inducible gene expression, particularly when both glucose and nitrogen were present in high levels. To avoid adding unwanted peptide to proteins to be expressed, we converted the original translation initiation codon to ATC and re-created a translation initiation codon at the start of exon 2. This promoter, named PDAO1-in1m1, showed very similar luciferase activity to the wild-type promoter upon induction with d-alanine. The inducible system was tunable by adjusting the levels of inducers, carbon source and nitrogen source. Conclusion The intron 1-containing DAO1 promoters coupled with a DAO1 null mutant makes an efficient and tight d-amino acid-inducible gene expression system in Rhodosporidium and Rhodotorula genera. The system will be a valuable tool for metabolic engineering and enzyme expression in these yeast hosts. Electronic supplementary material The online version of this article (doi:10.1186/s12934-015-0357-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yanbin Liu
- Biomaterials and Biocatalysts Group, Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore, 117604, Singapore
| | - Chong Mei John Koh
- Biomaterials and Biocatalysts Group, Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore, 117604, Singapore
| | - Si Te Ngoh
- Biomaterials and Biocatalysts Group, Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore, 117604, Singapore
| | - Lianghui Ji
- Biomaterials and Biocatalysts Group, Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore, 117604, Singapore.
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Sun X, He G, Wang X, Xu S, Ju J, Xu X. Crystal Structure of a Thermostable Alanine Racemase from Thermoanaerobacter tengcongensis MB4 Reveals the Role of Gln360 in Substrate Selection. PLoS One 2015. [PMID: 26218070 PMCID: PMC4517790 DOI: 10.1371/journal.pone.0133516] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Pyridoxal 5’-phosphate (PLP) dependent alanine racemase catalyzes racemization of L-Ala to D-Ala, a key component of the peptidoglycan network in bacterial cell wall. It has been extensively studied as an important antimicrobial drug target due to its restriction in eukaryotes. However, many marketed alanine racemase inhibitors also act on eukaryotic PLP-dependent enzymes and cause side effects. A thermostable alanine racemase (AlrTt) from Thermoanaerobacter tengcongensis MB4 contains an evolutionarily non-conserved residue Gln360 in inner layer of the substrate entryway, which is supposed to be a key determinant in substrate specificity. Here we determined the crystal structure of AlrTt in complex with L-Ala at 2.7 Å resolution, and investigated the role of Gln360 by saturation mutagenesis and kinetic analysis. Compared to typical bacterial alanine racemase, presence of Gln360 and conformational changes of active site residues disrupted the hydrogen bonding interactions necessary for proper PLP immobilization, and decreased both the substrate affinity and turnover number of AlrTt. However, it could be complemented by introduction of hydrophobic amino acids at Gln360, through steric blocking and interactions with a hydrophobic patch near active site pocket. These observations explained the low racemase activity of AlrTt, revealed the essential role of Gln360 in substrate selection, and its preference for hydrophobic amino acids especially Tyr in bacterial alanine racemization. Our work will contribute new insights into the alanine racemization mechanism for antimicrobial drug development.
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Affiliation(s)
- Xiaoliang Sun
- Institute of Ageing Research, School of Medicine, Hangzhou Normal University, Hangzhou, China
| | - Guangzheng He
- College of Life Science, Hebei Normal University, Shijiazhuang, China
| | - Xiaoyan Wang
- Institute of Ageing Research, School of Medicine, Hangzhou Normal University, Hangzhou, China
| | - Shujing Xu
- College of Life Science, Hebei Normal University, Shijiazhuang, China
| | - Jiansong Ju
- College of Life Science, Hebei Normal University, Shijiazhuang, China
- * E-mail: (JSJ); (XLX)
| | - Xiaoling Xu
- Institute of Ageing Research, School of Medicine, Hangzhou Normal University, Hangzhou, China
- * E-mail: (JSJ); (XLX)
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16
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Affiliation(s)
- Mohammed Afzal Azam
- Department of Pharmaceutical Chemistry, JSS College of Pharmacy, Udhagamandalam, Tamil Nadu, India
| | - Unni Jayaram
- Department of Pharmaceutical Chemistry, JSS College of Pharmacy, Udhagamandalam, Tamil Nadu, India
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17
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Racemization in reverse: evidence that D-amino acid toxicity on Earth is controlled by bacteria with racemases. PLoS One 2014; 9:e92101. [PMID: 24647559 PMCID: PMC3960212 DOI: 10.1371/journal.pone.0092101] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 02/17/2014] [Indexed: 11/19/2022] Open
Abstract
D-amino acids are toxic for life on Earth. Yet, they form constantly due to geochemical racemization and bacterial growth (the cell walls of which contain D-amino acids), raising the fundamental question of how they ultimately are recycled. This study provides evidence that bacteria use D-amino acids as a source of nitrogen by running enzymatic racemization in reverse. Consequently, when soils are inundated with racemic amino acids, resident bacteria consume D- as well as L-enantiomers, either simultaneously or sequentially depending on the level of their racemase activity. Bacteria thus protect life on Earth by keeping environments D-amino acid free.
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18
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Gilbert C, Cordaux R. Horizontal transfer and evolution of prokaryote transposable elements in eukaryotes. Genome Biol Evol 2013; 5:822-32. [PMID: 23563966 PMCID: PMC3673617 DOI: 10.1093/gbe/evt057] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Horizontal transfer (HT) of transposable elements (TEs) plays a key role in prokaryotic evolution, and mounting evidence suggests that it has also had an important impact on eukaryotic evolution. Although many prokaryote-to-prokaryote and eukaryote-to-eukaryote HTs of TEs have been characterized, only few cases have been reported between prokaryotes and eukaryotes. Here, we carried out a comprehensive search for all major groups of prokaryotic insertion sequences (ISs) in 430 eukaryote genomes. We uncovered a total of 80 sequences, all deriving from the IS607 family, integrated in the genomes of 14 eukaryote species belonging to four distinct phyla (Amoebozoa, Ascomycetes, Basidiomycetes, and Stramenopiles). Given that eukaryote IS607-like sequences are most closely related to cyanobacterial IS607 and that their phylogeny is incongruent with that of their hosts, we conclude that the presence of IS607-like sequences in eukaryotic genomes is the result of several HT events. Selection analyses further suggest that our ability to detect these prokaryote TEs today in eukaryotes is because HT of these sequences occurred recently and/or some IS607 elements were domesticated after HT, giving rise to new eukaryote genes. Supporting the recent age of some of these HTs, we uncovered intact full-length, potentially active IS607 copies in the amoeba Acanthamoeba castellani. Overall, our study shows that prokaryote-to-eukaryote HT of TEs occurred at relatively low frequency during recent eukaryote evolution and it sets IS607 as the most widespread TE (being present in prokaryotes, eukaryotes, and viruses).
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Affiliation(s)
- Clément Gilbert
- Université de Poitiers, UMR CNRS 7267 Ecologie et Biologie des Interactions, Equipe Ecologie Evolution Symbiose, Poitiers, France.
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19
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Wu HM, Kuan YC, Chu CH, Hsu WH, Wang WC. Crystal structures of lysine-preferred racemases, the non-antibiotic selectable markers for transgenic plants. PLoS One 2012; 7:e48301. [PMID: 23118975 PMCID: PMC3485190 DOI: 10.1371/journal.pone.0048301] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 09/24/2012] [Indexed: 11/18/2022] Open
Abstract
Lysine racemase, a pyridoxal 5′-phosphate (PLP)-dependent amino acid racemase that catalyzes the interconversion of lysine enantiomers, is valuable to serve as a novel non-antibiotic selectable marker in the generation of transgenic plants. Here, we have determined the first crystal structure of a lysine racemase (Lyr) from Proteus mirabilis BCRC10725, which shows the highest activity toward lysine and weaker activity towards arginine. In addition, we establish the first broad-specificity amino acid racemase (Bar) structure from Pseudomonas putida DSM84, which presents not only the highest activity toward lysine but also remarkably broad substrate specificity. A complex structure of Bar-lysine is also established here. These structures demonstrate the similar fold of alanine racemase, which is a head-to-tail homodimer with each protomer containing an N-terminal (α/β)8 barrel and a C-terminal β-stranded domain. The active-site residues are located at the protomer interface that is a funnel-like cavity with two catalytic bases, one from each protomer, and the PLP binding site is at the bottom of this cavity. Structural comparisons, site-directed mutagenesis, kinetic, and modeling studies identify a conserved arginine and an adjacent conserved asparagine that fix the orientation of the PLP O3 atom in both structures and assist in the enzyme activity. Furthermore, side chains of two residues in α-helix 10 have been discovered to point toward the cavity and define the substrate specificity. Our results provide a structural foundation for the design of racemases with pre-determined substrate specificity and for the development of the non-antibiotic selection system in transgenic plants.
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Affiliation(s)
- Hsin-Mao Wu
- Institute of Molecular and Cellular Biology and Department of Life Science, National Tsing Hua University, Hsinchu, Taiwan
| | - Yi-Chia Kuan
- Institute of Molecular Biology, National Chung Hsing University, Taichung, Taiwan
| | - Chia-Han Chu
- Biomedical Science and Engineering Center, National Tsing Hua University, Hsinchu, Taiwan
| | - Wen-Hwei Hsu
- Institute of Molecular Biology, National Chung Hsing University, Taichung, Taiwan
| | - Wen-Ching Wang
- Institute of Molecular and Cellular Biology and Department of Life Science, National Tsing Hua University, Hsinchu, Taiwan
- Biomedical Science and Engineering Center, National Tsing Hua University, Hsinchu, Taiwan
- * E-mail:
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20
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D-amino acid-induced expression of D-amino acid oxidase in the yeast Schizosaccharomyces pombe. Curr Microbiol 2012; 65:764-9. [PMID: 22986818 DOI: 10.1007/s00284-012-0227-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Accepted: 08/10/2012] [Indexed: 10/27/2022]
Abstract
We investigated D-amino acid oxidase (DAO) induction in the popular model yeast Schizosaccharomyces pombe. The product of the putative DAO gene of the yeast expressed in E. coli displayed oxidase activity to neutral and basic D-amino acids, but not to an L-amino acid or acidic D-amino acids, showing that the putative DAO gene encodes catalytically active DAO. DAO activity was weakly detected in yeast cells grown on a culture medium without D-amino acid, and was approximately doubled by adding D-alanine. The elimination of ammonium chloride from culture medium induced activity by up to eight-fold. L-Alanine also induced the activity, but only by about half of that induced by D-alanine. The induction by D-alanine reached a maximum level at 2 h cultivation; it remained roughly constant until cell growth reached a stationary phase. The best inducer was D-alanine, followed by D-proline and then D-serine. Not effective were N-carbamoyl-D,L-alanine (a better inducer of DAO than D-alanine in the yeast Trigonopsis variabilis), and both basic and acidic D-amino acids. These results showed that S. pombe DAO could be a suitable model for analyzing the regulation of DAO expression in eukaryotic organisms.
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21
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Scaletti ER, Luckner SR, Krause KL. Structural features and kinetic characterization of alanine racemase from Staphylococcus aureus (Mu50). ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2012; 68:82-92. [PMID: 22194336 PMCID: PMC3245724 DOI: 10.1107/s0907444911050682] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Accepted: 11/25/2011] [Indexed: 11/10/2022]
Abstract
Staphylococcus aureus is an opportunistic Gram-positive bacterium which causes a wide variety of diseases ranging from minor skin infections to potentially fatal conditions such as pneumonia, meningitis and septicaemia. The pathogen is a leading cause of nosocomial acquired infections, a problem that is exacerbated by the existence of methicillin- and glycopeptide antibiotic-resistant strains which can be challenging to treat. Alanine racemase (Alr) is a pyridoxal-5'-phosphate-dependent enzyme which catalyzes reversible racemization between enantiomers of alanine. As D-alanine is an essential component of the bacterial cell-wall peptidoglycan, inhibition of Alr is lethal to prokaryotes. Additionally, while ubiquitous amongst bacteria, this enzyme is absent in humans and most eukaryotes, making it an excellent antibiotic drug target. The crystal structure of S. aureus alanine racemase (Alr(Sas)), the sequence of which corresponds to that from the highly antibiotic-resistant Mu50 strain, has been solved to 2.15 Å resolution. Comparison of the Alr(Sas) structure with those of various alanine racemases demonstrates a conserved overall fold, with the enzyme sharing most similarity to those from other Gram-positive bacteria. Structural examination indicates that the active-site binding pocket, dimer interface and active-site entryway of the enzyme are potential targets for structure-aided inhibitor design. Kinetic constants were calculated in this study and are reported here. The potential for a disulfide bond in this structure is noted. This structural and biochemical information provides a template for future structure-based drug-development efforts targeting Alr(Sas).
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Affiliation(s)
- Emma R. Scaletti
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - Sylvia R. Luckner
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - Kurt L. Krause
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
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22
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Abstract
D-Amino acids play important physiological roles in the mammalian body. Recent investigations revealed that, in mammals, D-amino acids are synthesized from their corresponding L-enantiomers via amino acid racemase. This article describes a method used to measure amino acid racemase activity by high-performance liquid chromatography (HPLC). The assay involves fluorogenic chiral derivatization of amino acids with a newly developed reagent, and enantioseparation of D- and L-amino acid derivatives by HPLC. The method is accurate and reliable, and can be automated using a programmable autosampling injector.
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Affiliation(s)
- Masumi Katane
- Department of Pharmaceutical Life Sciences, Kitasato University, Minatoku, Tokyo, Japan
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23
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Thiadiazolidinones: a new class of alanine racemase inhibitors with antimicrobial activity against methicillin-resistant Staphylococcus aureus. Biochem Pharmacol 2011; 83:368-77. [PMID: 22146584 DOI: 10.1016/j.bcp.2011.11.021] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Revised: 11/20/2011] [Accepted: 11/21/2011] [Indexed: 11/21/2022]
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is a human pathogen and a major cause of hospital-acquired infections. New antibacterial agents that have not been compromised by bacterial resistance are needed to treat MRSA-related infections. We chose the S. aureus cell wall synthesis enzyme, alanine racemase (Alr) as the target for a high-throughput screening effort to obtain novel enzyme inhibitors, which inhibit bacterial growth. Among the 'hits' identified was a thiadiazolidinone with chemical properties attractive for lead development. This study evaluated the mode of action, antimicrobial activities, and mammalian cell cytotoxicity of the thiadiazolidinone family in order to assess its potential for development as a therapeutic agent against MRSA. The thiadiazolidones inhibited Alr activity with 50% inhibitory concentrations (IC₅₀) ranging from 0.36 to 6.4 μM, and they appear to inhibit the enzyme irreversibly. The series inhibited the growth of S. aureus, including MRSA strains, with minimal inhibitory concentrations (MICs) ranging from 6.25 to 100 μg/ml. The antimicrobial activity showed selectivity against Gram-positive bacteria and fungi, but not Gram-negative bacteria. The series inhibited human HeLa cell proliferation. Lead development centering on the thiadiazolidinone series would require additional medicinal chemistry efforts to enhance the antibacterial activity and minimize mammalian cell toxicity.
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24
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Kuan YC, Kao CH, Chen CH, Chen CC, Hu HY, Hsu WH. Biochemical characterization of a novel lysine racemase from Proteus mirabilis BCRC10725. Process Biochem 2011. [DOI: 10.1016/j.procbio.2011.06.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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25
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Conti P, Tamborini L, Pinto A, Blondel A, Minoprio P, Mozzarelli A, De Micheli C. Drug Discovery Targeting Amino Acid Racemases. Chem Rev 2011; 111:6919-46. [DOI: 10.1021/cr2000702] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Paola Conti
- Dipartimento di Scienze Farmaceutiche “P. Pratesi”, via Mangiagalli 25, 20133 Milano, Italy
| | - Lucia Tamborini
- Dipartimento di Scienze Farmaceutiche “P. Pratesi”, via Mangiagalli 25, 20133 Milano, Italy
| | - Andrea Pinto
- Dipartimento di Scienze Farmaceutiche “P. Pratesi”, via Mangiagalli 25, 20133 Milano, Italy
| | - Arnaud Blondel
- Institut Pasteur, Unité de Bioinformatique Structurale, CNRS-URA 2185, Département de Biologie Structurale et Chimie, 25 rue du Dr. Roux, 75724 Paris, France
| | - Paola Minoprio
- Institut Pasteur, Laboratoire des Processus Infectieux à Trypanosoma; Département d’Infection et Epidémiologie; 25 rue du Dr. Roux, 75724 Paris, France
| | - Andrea Mozzarelli
- Dipartimento di Biochimica e Biologia Molecolare, via G. P. Usberti 23/A, 43100 Parma, Italy
- Istituto di Biostrutture e Biosistemi, viale Medaglie d’oro, Roma, Italy
| | - Carlo De Micheli
- Dipartimento di Scienze Farmaceutiche “P. Pratesi”, via Mangiagalli 25, 20133 Milano, Italy
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Würges K, Mackfeld U, Pohl M, Lütz S, Wilhelm S, Wiechert W, Kubitzki T. An Efficient Route to Both Enantiomers of allo-Threonine by Simultaneous Amino Acid Racemase-Catalyzed Isomerization of Threonine and Crystallization. Adv Synth Catal 2011. [DOI: 10.1002/adsc.201100051] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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27
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Rhind N, Chen Z, Yassour M, Thompson DA, Haas BJ, Habib N, Wapinski I, Roy S, Lin MF, Heiman DI, Young SK, Furuya K, Guo Y, Pidoux A, Chen HM, Robbertse B, Goldberg JM, Aoki K, Bayne EH, Berlin AM, Desjardins CA, Dobbs E, Dukaj L, Fan L, FitzGerald MG, French C, Gujja S, Hansen K, Keifenheim D, Levin JZ, Mosher RA, Müller CA, Pfiffner J, Priest M, Russ C, Smialowska A, Swoboda P, Sykes SM, Vaughn M, Vengrova S, Yoder R, Zeng Q, Allshire R, Baulcombe D, Birren BW, Brown W, Ekwall K, Kellis M, Leatherwood J, Levin H, Margalit H, Martienssen R, Nieduszynski CA, Spatafora JW, Friedman N, Dalgaard JZ, Baumann P, Niki H, Regev A, Nusbaum C. Comparative functional genomics of the fission yeasts. Science 2011; 332:930-6. [PMID: 21511999 DOI: 10.1126/science.1203357] [Citation(s) in RCA: 370] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The fission yeast clade--comprising Schizosaccharomyces pombe, S. octosporus, S. cryophilus, and S. japonicus--occupies the basal branch of Ascomycete fungi and is an important model of eukaryote biology. A comparative annotation of these genomes identified a near extinction of transposons and the associated innovation of transposon-free centromeres. Expression analysis established that meiotic genes are subject to antisense transcription during vegetative growth, which suggests a mechanism for their tight regulation. In addition, trans-acting regulators control new genes within the context of expanded functional modules for meiosis and stress response. Differences in gene content and regulation also explain why, unlike the budding yeast of Saccharomycotina, fission yeasts cannot use ethanol as a primary carbon source. These analyses elucidate the genome structure and gene regulation of fission yeast and provide tools for investigation across the Schizosaccharomyces clade.
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Affiliation(s)
- Nicholas Rhind
- Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605, USA.
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Removal of l-alanine from the production of l-2-aminobutyric acid by introduction of alanine racemase and d-amino acid oxidase. Appl Microbiol Biotechnol 2011; 90:903-10. [DOI: 10.1007/s00253-011-3127-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Revised: 01/10/2011] [Accepted: 01/10/2011] [Indexed: 10/18/2022]
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Marcet-Houben M, Gabaldón T. Acquisition of prokaryotic genes by fungal genomes. Trends Genet 2009; 26:5-8. [PMID: 19969385 DOI: 10.1016/j.tig.2009.11.007] [Citation(s) in RCA: 159] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2009] [Revised: 11/10/2009] [Accepted: 11/10/2009] [Indexed: 10/20/2022]
Abstract
The relevance of horizontal gene transfer (HGT) in eukaryotes is a matter of debate. Recent analyses have shown clear examples in some species such as Candida parapsilosis, but broader surveys are lacking. To assess the impact of HGT in the fungal kingdom, we searched for prokaryotic-derived HGTs in 60 fully sequenced genomes. Using strict phylogenomic criteria, we detected 713 transferred genes. HGT affected most fungal clades, with particularly high rates in Pezizomycotina. Transferred genes included bacterial arsenite reductase, catalase, different racemases and peptidoglycan metabolism enzymes. Our results suggest an important role for HGT in fungal evolution.
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Affiliation(s)
- Marina Marcet-Houben
- Bioinformatics and Genomics Programme, Centre for Genomic Regulation, Doctor Aiguader, 88. 08003 Barcelona, Spain
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Isolation and characterization of a novel lysine racemase from a soil metagenomic library. Appl Environ Microbiol 2009; 75:5161-6. [PMID: 19502445 DOI: 10.1128/aem.00074-09] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
A lysine racemase (lyr) gene was isolated from a soil metagenome by functional complementation for the first time by using Escherichia coli BCRC 51734 cells as the host and d-lysine as the selection agent. The lyr gene consisted of a 1,182-bp nucleotide sequence encoding a protein of 393 amino acids with a molecular mass of about 42.7 kDa. The enzyme exhibited higher specific activity toward lysine in the l-lysine-to-d-lysine direction than in the reverse reaction.
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Characterization of endogenous pyridoxal 5′-phosphate-dependent alanine racemase from Bacillus pseudofirmus OF4. J Biosci Bioeng 2009; 107:225-9. [DOI: 10.1016/j.jbiosc.2008.11.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2008] [Revised: 10/30/2008] [Accepted: 11/05/2008] [Indexed: 11/24/2022]
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Gogami Y, Ito K, Kamitani Y, Matsushima Y, Oikawa T. Occurrence of D-serine in rice and characterization of rice serine racemase. PHYTOCHEMISTRY 2009; 70:380-7. [PMID: 19249065 DOI: 10.1016/j.phytochem.2009.01.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2008] [Revised: 12/29/2008] [Accepted: 01/13/2009] [Indexed: 05/03/2023]
Abstract
Germinated, unpolished rice was found to contain a substantial amount of D-serine, with the ratio of the D-enantiomer to the L-enantiomer being higher for serine than for other amino acids. The relative amount of D-serine (D/(D+L)%) reached approximately 10% six days after germination. A putative serine racemase gene (serr, clone No. 001-110-B03) was found in chromosome 4 of the genomic DNA of Oryza sativa L. ssp. Japonica cv. Nipponbare. This was expressed as serr in Escherichia coli and its gene product (SerR) was purified to apparent homogeneity. SerR is a homodimer with a subunit molecular mass of 34.5kDa, and is highly specific for serine. In addition to a serine racemase reaction, SerR catalyzes D- and L-serine dehydratase reactions, for which the specific activities were determined to be 2.73 and 1.42nkatal/mg, respectively. The optimum temperature and pH were respectively determined for the racemase reaction (35 degrees C and pH9.0) and for the dehydratase reaction (35 degrees C and pH9.5). SerR was inhibited by PLP-enzyme inhibitors. ATP decreased the serine racemase activity of SerR but increased the serine dehydratase activity. Kinetic analysis showed that Mg(2+) increases the catalytic efficiency of the serine racemase activity of SerR and decreases that of the serine dehydratase activity. Fluorescence-quenching analysis of the tryptophan residues in SerR indicated that the structure of SerR is distorted by the addition of Mg(2+), and this structural change probably regulates the two enzymatic activities.
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Affiliation(s)
- Yoshitaka Gogami
- Department of Life Science and Biotechnology, Faculty of Chemistry, Materials, and Bioengineering, Kansai University, 3-3-35 Yamate-Cho, Suita, Osaka-Fu 564-8680, Japan
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Ju J, Qi J, Xu S, Ohnishi K, Benedik MJ, Xue Y, Ma Y. Crystallization and preliminary X-ray study of alkaline alanine racemase from Bacillus pseudofirmus OF4. Acta Crystallogr Sect F Struct Biol Cryst Commun 2009; 65:166-8. [PMID: 19194012 PMCID: PMC2635857 DOI: 10.1107/s174430910900013x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2008] [Accepted: 01/03/2009] [Indexed: 11/10/2022]
Abstract
Alanine racemase (DadX(OF4)), a dimeric endogenous PLP-dependent alkaline enzyme from alkaliphilic Bacillus pseudofirmus OF4, was expressed in Escherichia coli and purified with a His(6) tag in a form suitable for X-ray crystallographic analysis. Crystals were grown by the hanging-drop vapour-diffusion method at 291 K using a solution containing 1.4 M sodium/potassium phosphate pH 8.2. The protein crystallized in space group P2(1)2(1)2(1), with two protein molecules in the asymmetric unit.
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Affiliation(s)
- Jiansong Ju
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, People’s Republic of China
| | - Jianxun Qi
- Institute of Physics, Chinese Academy of Sciences, Beijing 100049, People’s Republic of China
| | - Shujing Xu
- Life College of Science and Engineering, Shaanxi University of Science and Technology, Xi’an 710021, People’s Republic of China
| | - Kouhei Ohnishi
- Research Institute of Molecular Genetics, Kochi University, Nankoku, Kochi 783-8502, Japan
| | - Michael J. Benedik
- Department of Biology, Texas A&M University, College Station, TX 77843-3258, USA
| | - Yanfen Xue
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, People’s Republic of China
| | - Yanhe Ma
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, People’s Republic of China
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Yoshikawa N, Okada S, Abe H. Molecular Characterization of Alanine Racemase in the Kuruma Prawn Marsupenaeus japonicus. J Biochem 2008; 145:249-58. [DOI: 10.1093/jb/mvn162] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Yoshimura T, Goto M. D-amino acids in the brain: structure and function of pyridoxal phosphate-dependent amino acid racemases. FEBS J 2008; 275:3527-37. [PMID: 18564179 DOI: 10.1111/j.1742-4658.2008.06516.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
D-serine serves as a co-agonist of the N-methyl D-aspartate receptor in mammalian brains, and its behavior is probably related to neurological disorders such as schizophrenia, Alzheimer's disease and amyotrophic lateral sclerosis. D-Serine is synthesized by a pyridoxal 5'-phosphate (PLP)-dependent serine racemase. In this minireview, we provide a detailed discussion on the reaction mechanism of the PLP-dependent amino acid racemase on the basis of its 3D structure. We compared the eukaryotic serine racemase with bacterial alanine racemase, the best-studied enzyme among the PLP-dependent amino acid racemases, and thus suggested a putative reaction mechanism for mammalian D-serine synthesis.
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Affiliation(s)
- Tohru Yoshimura
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi, Japan.
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36
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Wu D, Hu T, Zhang L, Chen J, Du J, Ding J, Jiang H, Shen X. Residues Asp164 and Glu165 at the substrate entryway function potently in substrate orientation of alanine racemase from E. coli: Enzymatic characterization with crystal structure analysis. Protein Sci 2008; 17:1066-76. [PMID: 18434499 DOI: 10.1110/ps.083495908] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Alanine racemase (Alr) is an important enzyme that catalyzes the interconversion of L-alanine and D-alanine, an essential building block in the peptidoglycan biosynthesis. For the small size of the Alr active site, its conserved substrate entryway has been proposed as a potential choice for drug design. In this work, we fully analyzed the crystal structures of the native, the D-cycloserine-bound, and four mutants (P219A, E221A, E221K, and E221P) of biosynthetic Alr from Escherichia coli (EcAlr) and studied the potential roles in substrate orientation for the key residues involved in the substrate entryway in conjunction with the enzymatic assays. Structurally, it was discovered that EcAlr is similar to the Pseudomonas aeruginosa catabolic Alr in both overall and active site geometries. Mutation of the conserved negatively charged residue aspartate 164 or glutamate 165 at the substrate entryway could obviously reduce the binding affinity of enzyme against the substrate and decrease the turnover numbers in both D- to L-Ala and L- to D-Ala directions, especially when mutated to lysine with the opposite charge. However, mutation of Pro219 or Glu221 had only negligible or a small influence on the enzymatic activity. Together with the enzymatic and structural investigation results, we thus proposed that the negatively charged residues Asp164 and Glu165 around the substrate entryway play an important role in substrate orientation with cooperation of the positively charged Arg280 and Arg300 on the opposite monomer. Our findings are expected to provide some useful structural information for inhibitor design targeting the substrate entryway of Alr.
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Affiliation(s)
- Dalei Wu
- Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, People's Republic of China
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Abstract
YGL196W of Saccharomyces cerevisiae encodes a putative protein that is unidentified but is predicted to have a motif similar to that of the N-terminal domain of the bacterial alanine racemase. In the present study we found that YGL196W encodes a novel D-serine dehydratase, which belongs to a different protein family from that of the known bacterial enzyme. The yeast D-serine dehydratase purified from recombinant Escherichia coli cells depends on pyridoxal 5′-phosphate and zinc, and catalyses the conversion of D-serine into pyruvate and ammonia with the Km and kcat values of 0.39 mM and 13.1 s−1 respectively. D-Threonine and β-Cl-D-alanine also serve as substrates with catalytic efficiencies which are approx. 3 and 2% of D-serine respectively. L-Serine, L-threonine and β-Cl-L-alanine are inert as substrates. Atomic absorption analysis revealed that the enzyme contains one zinc atom per enzyme monomer. The enzyme activities toward D-serine and D-threonine were decreased by EDTA treatment and recovered by the addition of Zn2+. Little recovery was observed with Mg2+, Mn2+, Ca2+, Ni2+, Cu2+, K+ or Na+. In contrast, the activity towards β-Cl-D-alanine was retained after EDTA treatment. These results suggest that zinc is involved in the elimination of the hydroxy group of D-serine and D-threonine. D-Serine dehydratase of S. cerevisiae is probably the first example of a eukaryotic D-serine dehydratase and that of a specifically zinc-dependent pyridoxal enzyme as well.
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38
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Francois JA, Kappock TJ. Alanine racemase from the acidophile Acetobacter aceti. Protein Expr Purif 2007; 51:39-48. [PMID: 16843006 DOI: 10.1016/j.pep.2006.05.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2006] [Revised: 05/26/2006] [Accepted: 05/27/2006] [Indexed: 11/21/2022]
Abstract
Acetobacter aceti converts ethanol to acetic acid, and survives acetic acid exposure by tolerating cytoplasmic acidification. Alanine racemase (Alr) is a pyridoxal 5' phosphate (PLP) -dependent enzyme that catalyzes the interconversion of the d- and l-isomers of alanine and has a basic pH optimum. Since d-alanine is essential for peptidoglycan biosynthesis, Alr must somehow function in the acidic cytoplasm of A. aceti. We report the partial purification of native A. aceti Alr (AaAlr) and evidence that it is a rather stable enzyme. The C-terminus of AaAlr has a strong resemblance to the ssrA-encoded protein degradation signal, which thwarted initial protein expression experiments. High-activity AaAlr forms lacking a protease recognition sequence were expressed in Escherichia coli and purified. Biophysical and enzymological experiments confirm that AaAlr is intrinsically acid-resistant, yet has the catalytic properties of an ordinary Alr.
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Affiliation(s)
- Julie A Francois
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA
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39
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Selective isotopic labeling of recombinant proteins using amino acid auxotroph strains. Methods Mol Biol 2007; 389:175-88. [PMID: 17951643 DOI: 10.1007/978-1-59745-456-8_13] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Labeling proteins with stable isotopes is important for many analytical and structural techniques, including NMR spectroscopy and mass spectrometry. Nonselective labeling, which uniformly labels all amino acids in the protein, may be accomplished with readily available wild-type expression hosts. However, there are often advantages to labeling a specific amino acid, and residue-selective labeling generally requires the use of an expression strain that is auxotrophic for the amino acid in order to efficiently incorporate the isotopic label. The behavior of an auxotrophic strain may be complicated by the regulatory properties of the biosynthetic pathway, by secondary nutritional requirements resulting from disruption of a biosynthetic pathway, and from acquired sensitivity to environmental factors resulting from build-up of metabolic intermediates. As a result, it is important to characterize the phenotype of the each auxotrophic strain in order to optimize its performance as an expression host for selective labeling of proteins. The application of aromatic auxotroph strains of Pichia pastoris to labeling tyrosines in a recombinant protein (galactose oxidase) will be used to illustrate selective-labeling methods.
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40
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Oikawa T, Tauch A, Schaffer S, Fujioka T. Expression of alr gene from Corynebacterium glutamicum ATCC 13032 in Escherichia coli and molecular characterization of the recombinant alanine racemase. J Biotechnol 2006; 125:503-12. [PMID: 16707184 DOI: 10.1016/j.jbiotec.2006.04.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2005] [Revised: 03/18/2006] [Accepted: 04/04/2006] [Indexed: 11/28/2022]
Abstract
We constructed the high-expression system of the alr gene from Corynebacterium glutamicum ATCC 13032 in Escherichia coli BL 21 (DE3) to characterize the enzymological and structural properties of the gene product, Alr. The Alr was expressed in the soluble fractions of the cell extract of the E. coli clone and showed alanine racemase activity. The purified Alr was a dimer with a molecular mass of 78 kDa. The Alr required pyridoxal 5'-phosphate (PLP) as a coenzyme and contained 2 mol of PLP per mol of the enzyme. The holoenzyme showed maximum absorption at 420 nm, while the reduced form of the enzyme showed it at 310 nm. The Alr was specific for alanine, and the optimum pH was observed at about nine. The Alr was relatively thermostable, and its half-life time at 60 degrees C was estimated to be 26 min. The K(m) and V(max) values were determined as follows: l-alanine to d-alanine, K(m) (l-alanine) 5.01 mM and V(max) 306 U/mg; d-alanine to l-alanine, K(m) (d-alanine) 5.24 mM and V(max) 345 U/mg. The K(eq) value was calculated to be 1.07 and showed good agreement with the theoretical value for the racemization reaction. The high substrate specificity of the Alr from C. glutamicum ATCC 13032 is expected to be a biocatalyst for d-alanine production from the l-counter part.
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Affiliation(s)
- Tadao Oikawa
- Department of Biotechnology, Faculty of Engineering, Kansai University, 3-3-35 Yamate-Cho, Suita, Osaka-Fu 564-8680, Japan.
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41
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Nishimura K, Tomoda Y, Nakamoto Y, Kawada T, Ishii Y, Nagata Y. Alanine racemase from the green alga Chlamydomonas reinhardtii. Amino Acids 2006; 32:59-62. [PMID: 17469227 DOI: 10.1007/s00726-006-0352-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Chlamydomonas reinhardtii, a unicellular green microalga, could grow to a stationary phase having optical density of 2.0-2.5 at 750 nm in Tris-acetate-phosphate (TAP) medium containing 0.1% D-alanine. D-alanine has no inhibitory effect on growth and induced alanine racemase activity 130-fold more than without D-alanine in the green alga. Although C. reinhardtii cultured in the TAP medium showed alanine racemase activity, the content of free D-alanine was only 0.14%. The enzyme was partially purified by ammonium sulfate fractionation followed by three kinds of liquid chromatography using DEAE Toyopearl, Phenyl Sepharose, and TSK G3000 SWXL columns. The specific activity for L-alanine of the partially purified alanine racemase was 3.8 micromol/min/mg. The molecular weight of the enzyme was determined to be approximately 72,000 by gel filtration. The enzyme showed a maximum activity at 45 degrees C and pH 8.4 and requires pyridoxal 5'-phosphate as a coenzyme.
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Affiliation(s)
- K Nishimura
- Department of Applied Chemistry, Junior College, Nihon University, Chiba, Japan.
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42
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Ono K, Yanagida K, Oikawa T, Ogawa T, Soda K. Alanine racemase of alfalfa seedlings (Medicago sativa L.): first evidence for the presence of an amino acid racemase in plants. PHYTOCHEMISTRY 2006; 67:856-60. [PMID: 16616264 DOI: 10.1016/j.phytochem.2006.02.017] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2005] [Revised: 02/07/2006] [Accepted: 02/20/2006] [Indexed: 05/08/2023]
Abstract
We demonstrated several kinds of D-amino acids in plant seedlings, and moreover alanine racemase (E.C.5.1.1.1) in alfalfa (Medicago sativa L.) seedlings. This is the first evidence for the presence of amino acid racemase in plant. The enzyme was effectively induced by the addition of L- or D-alanine, and we highly purified the enzyme to show enzymological properties. The enzyme exclusively catalyzed racemization of L- and D-alanine. The K(m) and V(max) values of enzyme for L-alanine were 29.6 x 10(-3) M and 1.02 mol/s/kg, and those for D-alanine are 12.0 x 10(-3) M and 0.44 mol/s/kg, respectively. The K(eq) value was estimated to be about 1 and indicated that the enzyme catalyzes a typical racemization of both enantiomers of alanine. The enzyme was inactivated by hydroxylamine, phenylhydrazine and some other pyridoxal 5'-phosphate enzyme inhibitors. Accordingly, the enzyme required pyridoxal 5'-phosphate as a coenzyme, and enzymologically resembled bacterial alanine racemases studied so far.
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Affiliation(s)
- Kazutoshi Ono
- Department of Biotechnology, Faculty of Engineering, Kansai University, Suita-Shi, Osaka-Fu, Japan
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43
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Takahashi S, Kakuichi T, Fujii K, Kera Y, Yamada RH. Physiological role of D-aspartate oxidase in the assimilation and detoxification of D-aspartate in the yeast Cryptococcus humicola. Yeast 2006; 22:1203-12. [PMID: 16278929 DOI: 10.1002/yea.1303] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The physiological role of D-aspartate oxidase (ChDASPO) in the yeast Cryptococcus humicola was analysed through the growth characteristics of a ChDASPO gene-disrupted strain (daspoDelta) and the expression profile of ChDASPO on various combinations of carbon and nitrogen sources. The daspoDelta strain, constructed by homologous integration of the yeast URA3 marker, grew as well as the wild-type strain on ammonium chloride, L-aspartate or D-alanine as the sole nitrogen source. In contrast, the daspoDelta strain did not grow at all on D-aspartate, not only as the sole nitrogen source but also as the sole carbon source or as the sole nitrogen and carbon source, and grew more slowly than the wild-type strain on D-glutamate as the sole nitrogen source. In the wild-type strain, the induction of ChDASPO activity strictly depended on the presence of D-aspartate and was little affected by the co-presence of ammonium chloride, but it was significantly reduced by the co-presence of both glucose and ammonium chloride, which, however, did not abolish the induction, allowing considerable expression of ChDASPO. This expression pattern was consistent with that shown by Northern blot analysis. The daspoDelta strain was more sensitive than the wild-type to the growth retardation by acidic D-amino acids, but not to that by the corresponding L-isomers or D-alanine. These results clearly show that in the yeast, DASPO plays an essential role in the assimilation of D-aspartate and acts as a detoxifying agent for D-aspartate.
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Affiliation(s)
- Shouji Takahashi
- Department of Environmental Systems Engineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188, Japan.
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Yow GY, Uo T, Yoshimura T, Esaki N. Physiological role of D-amino acid-N-acetyltransferase of Saccharomyces cerevisiae: detoxification of D-amino acids. Arch Microbiol 2005; 185:39-46. [PMID: 16362288 DOI: 10.1007/s00203-005-0060-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2005] [Revised: 09/25/2005] [Accepted: 11/10/2005] [Indexed: 10/25/2022]
Abstract
Saccharomyces cerevisiae is sensitive to D-amino acids: those corresponding to almost all proteinous L-amino acids inhibit the growth of yeast even at low concentrations (e.g. 0.1 mM). We have determined that D-amino acid-N-acetyltransferase (DNT) of the yeast is involved in the detoxification of D-amino acids on the basis of the following findings. When the DNT gene was disrupted, the resulting mutant was far less tolerant to D-amino acids than the wild type. However, when the gene was overexpressed with a vector plasmid p426Gal1 in the wild type or the mutant S. cerevisiae as a host, the recombinant yeast, which was found to show more than 100 times higher DNT activity than the wild type, was much more tolerant to D-amino acids than the wild type. We further confirmed that, upon cultivation with D-phenylalanine, N-acetyl-D-phenylalanine was accumulated in the culture but not in the wild type and hpa3Delta cells overproducing DNT cells. Thus, D-amino acids are toxic to S. cerevisiae but are detoxified with DNT by N-acetylation preceding removal from yeast cells.
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Affiliation(s)
- Geok-Yong Yow
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, 611-0011, Kyoto-fu, Japan
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45
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Yoshimura T, Esak N. Amino acid racemases: functions and mechanisms. J Biosci Bioeng 2005; 96:103-9. [PMID: 16233494 DOI: 10.1016/s1389-1723(03)90111-3] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2003] [Accepted: 02/18/2003] [Indexed: 11/28/2022]
Abstract
L-Amino acids are predominant in living organisms, but D-amino acids such as D-alanine and D-glutamate also occur in all eubacterial cell walls. Moreover, even mammals contain endogenous D-amino acids: D-serine functions as a signaling molecule in mammalian brains, and D-aspartate acts as a mediator in endocrine systems. Various other D-amino acids have been demonstrated in archaea, yeasts, fungi, plants, insects, mollusks and other eucaryotic organisms. These D-amino acids are mostly endogenous and produced in most cases by racemization from their corresponding antipodes by the action of racemases. Therefore, amino acid racemases play a central role in D-amino acid metabolism. Most amino acid racemases require pyridoxal 5'-phosphate (PLP) as a coenzyme, but several others require no coenzymes. Recently, the structures and functions of these two classes of amino acid racemases were clarified on a molecular basis. We here describe recent advances in studies of the functions and mechanisms of PLP-dependent and -independent amino acid racemases.
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Affiliation(s)
- Tohru Yoshimura
- Laboratory of Microbial Biochemistry, Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
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Ju J, Yokoigawa K, Misono H, Ohnishi K. Cloning of alanine racemase genes from Pseudomonas fluorescens strains and oligomerization states of gene products expressed in Escherichia coli. J Biosci Bioeng 2005; 100:409-17. [PMID: 16310730 DOI: 10.1263/jbb.100.409] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2005] [Accepted: 06/08/2005] [Indexed: 11/17/2022]
Abstract
Bacterial alanine racemase (EC 5.1.1.1) is a pyridoxal 5'-phosphate-dependent enzyme. Almost all eubacteria known to date possess a biosynthetic alr gene and some bacteria have an additional catabolic dadX gene. On the basis of the subunit structure, alanine racemases are classified into two types, monomeric and homodimeric. Alanine racemase genes were cloned from two distinct Pseudomonas fluorescens strains, the psychrotrophic TM5-2 strain and the soil-borne LRB3W1 strain, by means of complementing an Escherichia coli alanine racemase-deficient mutant. From the cloning results, both strains are likely to possess only one alanine racemase gene, dadX, in the same manner as the other P. fluorescens strains. Gene organization surrounding the dadX gene is highly conserved among Pseudomonas strains. The gene for D-amino acid dehydrogenase is located adjacent to the dadX gene in both strains. The DadX alanine racemases were expressed in E. coli as C-terminal His-tagged fusion proteins and purified to homogeneity. The catalytic activity of LRB3W1 DadX was higher than that of TM5-2 DadX. The association states of P. fluorescens DadX subunits in the E. coli alanine racemase-deficient mutant were analyzed by gel filtration chromatography. Alanine racemase subunits were demonstrated to exist as both monomers and dimers. The enzyme was in a monomer-dimer equilibrium, and the catalytic activity of the enzyme was proportional to the equilibrium association constant for dimerization.
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Affiliation(s)
- Jiansong Ju
- Department of Applied Bioresource Science, The United Graduate School of Agricultural Sciences, Ehime University, 3-5-7 Tarumi, Matsuyama, Ehime 790-8566, Japan
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47
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Yow GY, Uo T, Yoshimura T, Esaki N. D-amino acid N-acetyltransferase of Saccharomyces cerevisiae: a close homologue of histone acetyltransferase Hpa2p acting exclusively on free D-amino acids. Arch Microbiol 2005; 182:396-403. [PMID: 15375647 DOI: 10.1007/s00203-004-0724-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
D-Amino acid N-acetyltransferase is a unique enzyme of Saccharomyces cerevisiae acting specifically on D-amino acids. The enzyme was found to be encoded by HPA3, a putative histone/protein acetyl transferase gene, and we purified its gene product, Hpa3p, from recombinant Escherichia coli cells. Hpa3p shares 49% sequence identity and 81% sequence similarity with a histone acetyltransferase, Hpa2p, of S. cerevisiae. Hpa3p acts on a wide range of D-amino acids but shows extremely low activity toward histone. However, Hpa2p does not act on any of the free amino acids except L-lysine and D-lysine. Kinetic analyses suggest that Hpa3p catalyzes the N-acetylation of D-amino acids through an ordered bi-bi mechanism, in which acetyl-CoA is the first substrate to be bound and CoA is the last product to be liberated.
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Affiliation(s)
- Geok-Yong Yow
- Institute for Chemical Research, Kyoto University, Uji, Japan
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Yamashita T, Ashiuchi M, Ohnishi K, Kato SI, Nagata S, Misono H. Molecular characterization of alanine racemase from Bifidobacterium bifidum. ACTA ACUST UNITED AC 2003. [DOI: 10.1016/s1381-1177(03)00083-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Yokoigawa K, Okubo Y, Soda K. Subunit interaction of monomeric alanine racemases from four Shigella species in catalytic reaction. FEMS Microbiol Lett 2003; 221:263-7. [PMID: 12725937 DOI: 10.1016/s0378-1097(03)00216-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Bacterial alanine racemases are classified into two types of subunit structure (monomer and homodimer). To clarify the catalytic unit of monomeric alanine racemases, we examined the apparent molecular mass of the monomeric alanine racemases from Shigella dysenteriae, Shigella boydii, Shigella flexneri, and Shigella sonnei by gel filtration in the presence of the substrate and inhibitor. The enzymes were eluted on gel filtration as a monomer of about 39,000 Da at low protein concentration and in the absence of L-alanine and D-cycloserine. An increase in the apparent molecular mass was induced by increasing the protein concentration or by adding the ligands in the elution buffer. The increase ratio depended on the ligand concentration, and the maximum apparent molecular masses of all enzymes were 60,000 and 76,000 Da in the presence of 100 mM L-alanine and 5 mM D-cycloserine, respectively. D-cycloserine may induce an inactive dimer and L-alanine may induce an intermediate between the monomer and dimer because of dynamic equilibrium. The apoenzyme also showed similar behavior in the presence of the ligands, but the increase ratios were lower than those of the holoenzymes. The Bacillus psychrosaccharolyticus alanine racemase, having a dimeric structure, showed a constant molecular mass irrespective of the absence or presence of the ligands. These results suggest that the monomeric Shigella Alr enzymes have a dimeric structure in the catalytic reaction. Substances that inhibit the subunit interaction of monomeric alanine racemases may be useful as a new type of antibacterial.
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Affiliation(s)
- Kumio Yokoigawa
- Department of Food Science and Nutrition, Nara Women's University, Japan.
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Strísovský K, Jirásková J, Barinka C, Majer P, Rojas C, Slusher BS, Konvalinka J. Mouse brain serine racemase catalyzes specific elimination of L-serine to pyruvate. FEBS Lett 2003; 535:44-8. [PMID: 12560076 DOI: 10.1016/s0014-5793(02)03855-3] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
D-Serine was previously identified in mammalian brain and was shown to be a co-agonist at the 'glycine' site of the N-methyl-D-aspartate (NMDA)-type receptors. Racemization of serine is catalyzed by serine racemase, a pyridoxal 5'-phosphate-dependent enzyme expressed mainly in brain and liver. NMDA receptor overactivation has been implicated in a number of pathological conditions and inhibitors of serine racemase are thus potentially interesting targets for therapy. We expressed recombinant mouse serine racemase in insect cells and purified it to near homogeneity. The enzyme is a non-covalent homodimer in solution and requires divalent cations Mg(2+), Ca(2+) or Mn(2+) for activity but not for dimerization. In addition to the racemization it also catalyzes specific elimination of L-Ser to pyruvate. D-Serine is eliminated much less efficiently. Both L-serine racemization and elimination activities of serine racemase are of comparable magnitude, display alkaline pH optimum and are negligible below pH 6.5.
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Affiliation(s)
- Kvido Strísovský
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo n.2, Praha 6, 166 10, Czech Republic.
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