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Dadi P, Pauling CW, Shrivastava A, Shah DD. Synthesis of versatile neuromodulatory molecules by a gut microbial glutamate decarboxylase. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.02.583032. [PMID: 38915512 PMCID: PMC11195143 DOI: 10.1101/2024.03.02.583032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
Dysbiosis of the microbiome correlates with many neurological disorders, yet very little is known about the chemistry that controls the production of neuromodulatory molecules by gut microbes. Here, we found that an enzyme glutamate decarboxylase ( Bf GAD) of a gut microbe Bacteroides fragilis forms multiple neuromodulatory molecules such as γ-aminobutyric acid (GABA), hypotaurine, taurine, homotaurine, and β-alanine. We evolved Bf GAD and doubled its taurine productivity. Additionally, we increased its specificity towards the substrate L-glutamate. Here, we provide a chemical strategy via which the Bf GAD activity could be fine-tuned. In future, this strategy could be used to modulate the production of neuromodulatory molecules by gut microbes.
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2
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Sasset L, Di Lorenzo A. Sphingolipid Metabolism and Signaling in Endothelial Cell Functions. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1372:87-117. [PMID: 35503177 DOI: 10.1007/978-981-19-0394-6_8] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The endothelium, inner layer of blood vessels, constitutes a metabolically active paracrine, endocrine, and autocrine organ, able to sense the neighboring environment and exert a variety of biological functions important to preserve the health of vasculature, tissues, and organs. Sphingolipids are both fundamental structural components of the eukaryotic membranes and signaling molecules regulating a variety of biological functions. Ceramide and sphingosine-1-phosphate (S1P), bioactive sphingolipids, have emerged as important regulators of cardiovascular functions in health and disease. In this review we discuss recent insights into the role of ceramide and S1P biosynthesis and signaling in regulating endothelial cell functions, in health and diseases. We also highlight advances into the mechanisms regulating serine palmitoyltransferase, the first and rate-limiting enzyme of de novo sphingolipid biosynthesis, with an emphasis on its inhibitors, ORMDL and NOGO-B. Understanding the molecular mechanisms regulating the sphingolipid de novo biosynthesis may provide the foundation for therapeutic modulation of this pathway in a variety of conditions, including cardiovascular diseases, associated with derangement of this pathway.
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Affiliation(s)
- Linda Sasset
- Department of Pathology and Laboratory Medicine, Cardiovascular Research Institute, Feil Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Annarita Di Lorenzo
- Department of Pathology and Laboratory Medicine, Cardiovascular Research Institute, Feil Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA.
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Semi-rational approach to expand the Acyl-CoA Chain length tolerance of Sphingomonas paucimobilis serine palmitoyltransferase. Enzyme Microb Technol 2020; 137:109515. [PMID: 32423667 DOI: 10.1016/j.enzmictec.2020.109515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 01/11/2020] [Accepted: 01/20/2020] [Indexed: 11/21/2022]
Abstract
Serine palmitoyltransferase (SPTase), the first enzyme of the sphingolipid biosynthesis pathway, produces 3-ketodihydrosphingosine by a Claisen-like condensation/decarboxylation reaction of l-Ser and palmitoyl-CoA (n-C16-CoA). Previous structural analysis of Sphingomonas paucimobilis SPTase (SpSPTase) revealed a dynamic active site loop (RPPATP; amino acids 378-383) in which R378 (underlined) forms a salt bridge with the carboxylic acid group of the PLP : l-Ser external aldimine. We hypothesized that this interaction might play a key role in acyl group substrate selectivity and therefore performed site-saturation mutagenesis at position 378 based on semi-rational design to expand tolerance for shorter acyl-CoA's. The resulting library was initially screened for the reaction between l-Ser and dodecanoyl-CoA (n-C12-CoA). The most interesting mutant (R378 K) was then purified and compared to wild-type SpSPTase against a panel of acyl-CoA's. These data showed that the R378 K substitution shifted the acyl group preference to shorter chain lengths, opening the possibility of using this and other engineered variants for biocatalytic C-C bond-forming reactions.
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Druggable Sphingolipid Pathways: Experimental Models and Clinical Opportunities. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1274:101-135. [PMID: 32894509 DOI: 10.1007/978-3-030-50621-6_6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Intensive research in the field of sphingolipids has revealed diverse roles in cell biological responses and human health and disease. This immense molecular family is primarily represented by the bioactive molecules ceramide, sphingosine, and sphingosine 1-phosphate (S1P). The flux of sphingolipid metabolism at both the subcellular and extracellular levels provides multiple opportunities for pharmacological intervention. The caveat is that perturbation of any single node of this highly regulated flux may have effects that propagate throughout the metabolic network in a dramatic and sometimes unexpected manner. Beginning with S1P, the receptors for which have thus far been the most clinically tractable pharmacological targets, this review will describe recent advances in therapeutic modulators targeting sphingolipids, their chaperones, transporters, and metabolic enzymes.
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Tavares NK, Stracey N, Brunold TC, Escalante-Semerena JC. The l-Thr Kinase/l-Thr-Phosphate Decarboxylase (CobD) Enzyme from Methanosarcina mazei Gö1 Contains Metallocenters Needed for Optimal Activity. Biochemistry 2019; 58:3260-3279. [PMID: 31268299 PMCID: PMC6667302 DOI: 10.1021/acs.biochem.9b00268] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The MM2060 (cobD) gene from Methanosarcina mazei strain Gö1 encodes a protein (MmCobD) with l-threonine kinase (PduX) and l-threonine-O-3-phosphate decarboxylase (CobD) activities. In addition to the unexpected l-Thr kinase activity, MmCobD has an extended carboxy-terminal (C-terminal) region annotated as a putative metal-binding zinc finger-like domain. Here, we demonstrate that the C-terminus of MmCobD is a ferroprotein containing ∼25 non-heme iron atoms per monomer of protein. The absence of the C-terminus substantially reduces, but does not abolish, enzymatic activities in vitro and in vivo. Single-residue substitutions of C-terminal putative Fe-binding cysteinyl and histidinyl residues resulted in the loss of Fe and changes in enzyme activity levels. Salmonella enterica ΔpduX and ΔcobD strains were used as heterologous hosts to assess coenzyme B12 biosynthesis as a function of 17 MmCobD variants tested. Some of the latter displayed 5-fold higher enzymatic activity in vitro and enhanced the growth rate of the S. enterica strains that synthesized them. Most of the MmCobD variants tested were up to 6-fold less active in vitro and supported slow growth rates of the S. enterica strains that synthesized them; some substitutions abolished enzyme activity. MmCobD exhibited an ultraviolet-visible absorption spectrum consistent with [4Fe-4S] clusters that appeared to be susceptible to oxidation by H2O2 and reduction by sodium dithionite. The presence of FeS clusters in MmCobD was corroborated by electron paramagnetic resonance and magnetic circular dichroism studies. Collectively, our results suggest that MmCobD contains one or more diamagnetic [4Fe-4S]2+ center(s) that may play a structural or regulatory role.
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Affiliation(s)
- Norbert K. Tavares
- Department of Microbiology, University of Georgia, Athens, Georgia 30602, USA
| | - Nuru Stracey
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706 USA
| | - Thomas C Brunold
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706 USA
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Harrison PJ, Gable K, Somashekarappa N, Kelly V, Clarke DJ, Naismith JH, Dunn TM, Campopiano DJ. Use of isotopically labeled substrates reveals kinetic differences between human and bacterial serine palmitoyltransferase. J Lipid Res 2019; 60:953-962. [PMID: 30792183 PMCID: PMC6495160 DOI: 10.1194/jlr.m089367] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 02/14/2019] [Indexed: 12/17/2022] Open
Abstract
Isotope labels are frequently used tools to track metabolites through complex biochemical pathways and to discern the mechanisms of enzyme-catalyzed reactions. Isotopically labeled l-serine is often used to monitor the activity of the first enzyme in sphingolipid biosynthesis, serine palmitoyltransferase (SPT), as well as labeling downstream cellular metabolites. Intrigued by the effect that isotope labels may be having on SPT catalysis, we characterized the impact of different l-serine isotopologues on the catalytic activity of recombinant SPT isozymes from humans and the bacterium Sphingomonas paucimobilis Our data show that S. paucimobilis SPT activity displays a clear isotope effect with [2,3,3-D]l-serine, whereas the human SPT isoform does not. This suggests that although both human and S. paucimobilis SPT catalyze the same chemical reaction, there may well be underlying subtle differences in their catalytic mechanisms. Our results suggest that it is the activating small subunits of human SPT that play a key role in these mechanistic variations. This study also highlights that it is important to consider the type and location of isotope labels on a substrate when they are to be used in in vitro and in vivo studies.
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Affiliation(s)
- Peter J Harrison
- EastChem School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, United Kingdom; Division of Structural Biology Wellcome Trust Centre for Human Genomics, Oxford OX3 7BN, United Kingdom; Research Complex at Harwell Rutherford Appleton Laboratory, Didcot OX11 0FA, United Kingdom
| | - Kenneth Gable
- Department of Biochemistry and Molecular Biology, Uniformed Services University, Bethesda, MD 20814-4799
| | | | - Van Kelly
- EastChem School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, United Kingdom
| | - David J Clarke
- EastChem School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, United Kingdom
| | - James H Naismith
- Division of Structural Biology Wellcome Trust Centre for Human Genomics, Oxford OX3 7BN, United Kingdom; Research Complex at Harwell Rutherford Appleton Laboratory, Didcot OX11 0FA, United Kingdom; The Rosalind Franklin Institute Rutherford Appleton Laboratory, Didcot OX11 0FA, United Kingdom
| | - Teresa M Dunn
- Department of Biochemistry and Molecular Biology, Uniformed Services University, Bethesda, MD 20814-4799
| | - Dominic J Campopiano
- EastChem School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, United Kingdom.
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Harrison PJ, Dunn T, Campopiano DJ. Sphingolipid biosynthesis in man and microbes. Nat Prod Rep 2018; 35:921-954. [PMID: 29863195 PMCID: PMC6148460 DOI: 10.1039/c8np00019k] [Citation(s) in RCA: 98] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Indexed: 12/20/2022]
Abstract
A new review covering up to 2018 Sphingolipids are essential molecules that, despite their long history, are still stimulating interest today. The reasons for this are that, as well as playing structural roles within cell membranes, they have also been shown to perform a myriad of cell signalling functions vital to the correct function of eukaryotic and prokaryotic organisms. Indeed, sphingolipid disregulation that alters the tightly-controlled balance of these key lipids has been closely linked to a number of diseases such as diabetes, asthma and various neuropathologies. Sphingolipid biogenesis, metabolism and regulation is mediated by a large number of enzymes, proteins and second messengers. There appears to be a core pathway common to all sphingolipid-producing organisms but recent studies have begun to dissect out important, species-specific differences. Many of these have only recently been discovered and in most cases the molecular and biochemical details are only beginning to emerge. Where there is a direct link from classic biochemistry to clinical symptoms, a number a drug companies have undertaken a medicinal chemistry campaign to try to deliver a therapeutic intervention to alleviate a number of diseases. Where appropriate, we highlight targets where natural products have been exploited as useful tools. Taking all these aspects into account this review covers the structural, mechanistic and regulatory features of sphingolipid biosynthetic and metabolic enzymes.
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Affiliation(s)
- Peter J. Harrison
- School of Chemistry
, University of Edinburgh
,
David Brewster Road
, Edinburgh
, EH9 3FJ
, UK
.
| | - Teresa M. Dunn
- Department of Biochemistry and Molecular Biology
, Uniformed Services University
,
Bethesda
, Maryland
20814
, USA
| | - Dominic J. Campopiano
- School of Chemistry
, University of Edinburgh
,
David Brewster Road
, Edinburgh
, EH9 3FJ
, UK
.
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Ren J, Snider J, Airola MV, Zhong A, Rana NA, Obeid LM, Hannun YA. Quantification of 3-ketodihydrosphingosine using HPLC-ESI-MS/MS to study SPT activity in yeast Saccharomyces cerevisiae. J Lipid Res 2017; 59:162-170. [PMID: 29092960 DOI: 10.1194/jlr.d078535] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 10/24/2017] [Indexed: 11/20/2022] Open
Abstract
Serine palmitoyltransferase (SPT) catalyzes the rate-limiting step of condensation of L-serine and palmitoyl-CoA to form 3-ketodihydrosphingosine (3KDS). Here, we report a HPLC-ESI-MS/MS method to directly quantify 3KDS generated by SPT. With this technique, we were able to detect 3KDS at a level comparable to that of dihydrosphingosine in yeast Saccharomyces cerevisiae An in vitro SPT assay measuring the incorporation of deuterated serine into deuterated 3KDS was developed. The results show that SPT kinetics in response to palmitoyl-CoA fit into an allosteric sigmoidal model, suggesting the existence of more than one palmitoyl-CoA binding site on yeast SPT and positive cooperativity between them. Myriocin inhibition of yeast SPT activity was also investigated and we report here, for the first time, an estimated myriocin Ki for yeast SPT of approximately 10 nM. Lastly, we investigated the fate of serine α-proton during SPT reaction. We provide additional evidence to support the proposed mechanism of SPT catalytic activity in regard to proton exchange between the intermediate NH3+ base formed on the active Lys residue with surrounding water. These findings establish the current method as a powerful tool with significant resolution and quantitative power to study SPT activity.
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Affiliation(s)
- Jihui Ren
- Departments of Medicine Stony Brook University, Stony Brook, NY 11794
| | - Justin Snider
- Departments of Medicine Stony Brook University, Stony Brook, NY 11794
| | - Michael V Airola
- Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794
| | - Aaron Zhong
- Departments of Medicine Stony Brook University, Stony Brook, NY 11794
| | - Nadia A Rana
- Departments of Medicine Stony Brook University, Stony Brook, NY 11794
| | - Lina M Obeid
- Departments of Medicine Stony Brook University, Stony Brook, NY 11794.,Stony Brook Cancer Center, Stony Brook University, Stony Brook, NY 11794.,Northport Veterans Affairs Medical Center, Northport, NY 11768
| | - Yusuf A Hannun
- Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794 .,Departments of Medicine Stony Brook University, Stony Brook, NY 11794.,Stony Brook Cancer Center, Stony Brook University, Stony Brook, NY 11794
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Duan J, Merrill AH. 1-Deoxysphingolipids Encountered Exogenously and Made de Novo: Dangerous Mysteries inside an Enigma. J Biol Chem 2015; 290:15380-15389. [PMID: 25947379 PMCID: PMC4505451 DOI: 10.1074/jbc.r115.658823] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The traditional backbones of mammalian sphingolipids are 2-amino, 1,3-diols made by serine palmitoyltransferase (SPT). Many organisms additionally produce non-traditional, cytotoxic 1-deoxysphingoid bases and, surprisingly, mammalian SPT biosynthesizes some of them, too (e.g. 1-deoxysphinganine from l-alanine). These are rapidly N-acylated to 1-deoxy-“ceramides” with very uncommon biophysical properties. The functions of 1-deoxysphingolipids are not known, but they are certainly dangerous as contributors to sensory and autonomic neuropathies when elevated by inherited SPT mutations, and they are noticeable in diabetes, non-alcoholic steatohepatitis, serine deficiencies, and other diseases. As components of food as well as endogenously produced, these substances are mysteries within an enigma.
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Affiliation(s)
- Jingjing Duan
- Schools of Biology and Chemistry & Biochemistry, and the Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332
| | - Alfred H Merrill
- Schools of Biology and Chemistry & Biochemistry, and the Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332.
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