1
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He Y, Collado JT, Iuliano JN, Woroniecka HA, Hall CR, Gil AA, Laptenok SP, Greetham GM, Illarionov B, Bacher A, Fischer M, French JB, Lukacs A, Meech SR, Tonge PJ. Elucidating the Signal Transduction Mechanism of the Blue-Light-Regulated Photoreceptor YtvA: From Photoactivation to Downstream Regulation. ACS Chem Biol 2024; 19:696-706. [PMID: 38385342 PMCID: PMC10949197 DOI: 10.1021/acschembio.3c00722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 01/25/2024] [Accepted: 02/12/2024] [Indexed: 02/23/2024]
Abstract
The blue-light photoreceptor YtvA from Bacillus subtilis has an N-terminal flavin mononucleotide (FMN)-binding light-oxygen-voltage (LOV) domain that is fused to a C-terminal sulfate transporter and anti-σ factor antagonist (STAS) output domain. To interrogate the signal transduction pathway that leads to photoactivation, the STAS domain was replaced with a histidine kinase, so that photoexcitation of the flavin could be directly correlated with biological activity. N94, a conserved Asn that is hydrogen bonded to the FMN C2═O group, was replaced with Ala, Asp, and Ser residues to explore the role of this residue in triggering the structural dynamics that activate the output domain. Femtosecond to millisecond time-resolved multiple probe spectroscopy coupled with a fluorescence polarization assay revealed that the loss of the hydrogen bond between N94 and the C2═O group decoupled changes in the protein structure from photoexcitation. In addition, alterations in N94 also decreased the stability of the Cys-FMN adduct formed in the light-activated state by up to a factor of ∼25. Collectively, these studies shed light on the role of the hydrogen bonding network in the LOV β-scaffold in signal transduction.
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Affiliation(s)
- YongLe He
- Department
of Chemistry, Stony Brook University, Stony Brook, New York 11794, United States
| | | | - James N. Iuliano
- Department
of Chemistry, Stony Brook University, Stony Brook, New York 11794, United States
| | - Helena A. Woroniecka
- Department
of Chemistry, Stony Brook University, Stony Brook, New York 11794, United States
| | - Christopher R. Hall
- Central
Laser Facility, Research Complex at Harwell, Rutherford Appleton Laboratory, Didcot OX11 0QX, U.K.
| | - Agnieszka A. Gil
- Department
of Chemistry, Stony Brook University, Stony Brook, New York 11794, United States
| | | | - Gregory M. Greetham
- Central
Laser Facility, Research Complex at Harwell, Rutherford Appleton Laboratory, Didcot OX11 0QX, U.K.
| | - Boris Illarionov
- Institut
für Biochemie und Lebensmittelchemie, Universität Hamburg, Grindelallee 117, D-20146 Hamburg, Germany
| | - Adelbert Bacher
- Institut
für Biochemie und Lebensmittelchemie, Universität Hamburg, Grindelallee 117, D-20146 Hamburg, Germany
- TUM School
of Natural Sciences, Technical University
of Munich, 85747 Garching, Germany
| | - Markus Fischer
- Institut
für Biochemie und Lebensmittelchemie, Universität Hamburg, Grindelallee 117, D-20146 Hamburg, Germany
| | - Jarrod B. French
- Department
of Chemistry, Stony Brook University, Stony Brook, New York 11794, United States
- The
Hormel Institute, University of Minnesota, Austin, Minnesota 55912, United States
| | - Andras Lukacs
- School
of Chemistry, University of East Anglia, Norwich NR4 7TJ, U.K.
- Department
of Biophysics, Medical School, University
of Pecs, Szigeti ut 12, 7624 Pecs, Hungary
| | - Stephen R. Meech
- School
of Chemistry, University of East Anglia, Norwich NR4 7TJ, U.K.
| | - Peter J. Tonge
- Department
of Chemistry, Stony Brook University, Stony Brook, New York 11794, United States
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2
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Lim SJ, Choi M, Yun I, Lee S, Chang N, Lee CY. Development of Fluorescent Bacteria with Lux and Riboflavin Genes. Int J Mol Sci 2023; 24:ijms24065096. [PMID: 36982169 PMCID: PMC10049116 DOI: 10.3390/ijms24065096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/03/2023] [Accepted: 03/05/2023] [Indexed: 03/30/2023] Open
Abstract
Lumazine protein from marine luminescent bacteria of Photobacterium species bind with very high affinity to the fluorescent chromophore 6,7-dimethyl-8-ribitylumazine. The light emission of bacterial luminescent systems is used as a sensitive, rapid, and safe assay for an ever-increasing number of biological systems. Plasmid pRFN4, containing the genes encoding riboflavin from the rib operon of Bacillus subtilis, was designed for the overproduction of lumazine. To construct fluorescent bacteria for use as microbial sensors, novel recombinant plasmids (pRFN4-Pp N-lumP and pRFN4-Pp luxLP N-lumP) were constructed by amplifying the DNA encoding the N-lumP gene (luxL) from P. phosphoreum and the promoter region (luxLP) present upstream of the lux operon of the gene by PCR and ligating into the pRFN4-Pp N-lumP plasmid. A new recombinant plasmid, pRFN4-Pp luxLP-N-lumP, was constructed with the expectation that the fluorescence intensity would be further increased when transformed into Escherichia coli. When this plasmid was transformed into E. coli 43R, the fluorescence intensity of transformants was 500 times greater than that of E. coli alone. As a result, the recombinant plasmid in which the gene encoding N-LumP and DNA containing the lux promoter exhibited expression that was so high as to show fluorescence in single E. coli cells. The fluorescent bacterial systems developed in the present study using lux and riboflavin genes can be utilized in the future as biosensors with high sensitivity and rapid analysis times.
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Affiliation(s)
- Sun-Joo Lim
- Department of Biochemistry, Chungnam National University, Daejeon 34134, Republic of Korea
| | - Miae Choi
- Department of Biochemistry, Chungnam National University, Daejeon 34134, Republic of Korea
| | - Inseop Yun
- Department of Biochemistry, Chungnam National University, Daejeon 34134, Republic of Korea
| | - Seulgi Lee
- Department of Biochemistry, Chungnam National University, Daejeon 34134, Republic of Korea
| | - Ny Chang
- Department of Biochemistry, Chungnam National University, Daejeon 34134, Republic of Korea
| | - Chan-Yong Lee
- Department of Biochemistry, Chungnam National University, Daejeon 34134, Republic of Korea
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3
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Lim S, Oh E, Choi M, Lee E, Lee CY. Generation of Fluorescent Bacteria with the Genes Coding for Lumazine Protein and Riboflavin Biosynthesis. SENSORS 2021; 21:s21134506. [PMID: 34209387 PMCID: PMC8272222 DOI: 10.3390/s21134506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 06/24/2021] [Accepted: 06/28/2021] [Indexed: 11/16/2022]
Abstract
Lumazine protein is a member of the riboflavin synthase superfamily and the intense fluorescence is caused by non-covalently bound to 6,7-dimethyl 8-ribityllumazine. The pRFN4 plasmid, which contains the riboflavin synthesis genes from Bacillus subtilis, was originally designed for overproduction of the fluorescent ligand of 6,7-dimethyl 8-ribityllumazine. To provide the basis for a biosensor based on the lux gene from bioluminescent bacteria of Photobacterium leiognathi, the gene coding for N-terminal domain half of the lumazine protein extending to amino acid 112 (N-LumP) and the gene for whole lumazine protein (W-LumP) from P. leiognathi were introduced by polymerase chain reaction (PCR) and ligated into pRFN4 vector, to construct the recombinant plasmids of N-lumP-pRFN4 and W-lumP-pRFN4 as well as their modified plasmids by insertion of the lux promoter. The expression of the genes in the recombinant plasmids was checked in various Escherichia coli strains, and the fluorescence intensity in Escherichia coli 43R can even be observed in a single cell. These results concerning the co-expression of the genes coding for lumazine protein and for riboflavin synthesis raise the possibility to generate fluorescent bacteria which can be used in the field of bio-imaging.
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4
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Iuliano JN, Hall CR, Green D, Jones GA, Lukacs A, Illarionov B, Bacher A, Fischer M, French JB, Tonge PJ, Meech SR. Excited State Vibrations of Isotopically Labeled FMN Free and Bound to a Light-Oxygen-Voltage (LOV) Protein. J Phys Chem B 2020; 124:7152-7165. [PMID: 32786715 PMCID: PMC7533957 DOI: 10.1021/acs.jpcb.0c04943] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Flavoproteins are important blue light sensors in photobiology and play a key role in optogenetics. The characterization of their excited state structure and dynamics is thus an important objective. Here, we present a detailed study of excited state vibrational spectra of flavin mononucleotide (FMN), in solution and bound to the LOV-2 (Light-Oxygen-Voltage) domain of Avena sativa phototropin. Vibrational frequencies are determined for the optically excited singlet state and the reactive triplet state, through resonant ultrafast femtosecond stimulated Raman spectroscopy (FSRS). To assign the observed spectra, vibrational frequencies of the excited states are calculated using density functional theory, and both measurement and theory are applied to four different isotopologues of FMN. Excited state mode assignments are refined in both states, and their sensitivity to deuteration and protein environment are investigated. We show that resonant FSRS provides a useful tool for characterizing photoactive flavoproteins and is able to highlight chromophore localized modes and to record hydrogen/deuterium exchange.
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Affiliation(s)
- James N. Iuliano
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | | | - Dale Green
- School of Chemistry, University of East Anglia, Norwich NR4 7TJ, U.K
| | - Garth A. Jones
- School of Chemistry, University of East Anglia, Norwich NR4 7TJ, U.K
| | - Andras Lukacs
- Department of Biophysics, Medical School, University of Pecs, Szigeti ut 12, 7624 Pecs, Hungary
| | - Boris Illarionov
- Institut für Biochemie und Lebensmittelchemie, Universität Hamburg, Grindelallee 117, D-20146 Hamburg, Germany
| | - Adelbert Bacher
- Institut für Biochemie und Lebensmittelchemie, Universität Hamburg, Grindelallee 117, D-20146 Hamburg, Germany
- Department of Chemistry, Technical University of Munich, 85747 Garching, Germany
| | - Markus Fischer
- Institut für Biochemie und Lebensmittelchemie, Universität Hamburg, Grindelallee 117, D-20146 Hamburg, Germany
| | - Jarrod B. French
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | - Peter J. Tonge
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | - Stephen R. Meech
- School of Chemistry, University of East Anglia, Norwich NR4 7TJ, U.K
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5
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Gil AA, Laptenok SP, French JB, Iuliano JN, Lukacs A, Hall CR, Sazanovich IV, Greetham GM, Bacher A, Illarionov B, Fischer M, Tonge PJ, Meech SR. Femtosecond to Millisecond Dynamics of Light Induced Allostery in the Avena sativa LOV Domain. J Phys Chem B 2017; 121:1010-1019. [PMID: 28068090 DOI: 10.1021/acs.jpcb.7b00088] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The rational engineering of photosensor proteins underpins the field of optogenetics, in which light is used for spatiotemporal control of cell signaling. Optogenetic elements function by converting electronic excitation of an embedded chromophore into structural changes on the microseconds to seconds time scale, which then modulate the activity of output domains responsible for biological signaling. Using time-resolved vibrational spectroscopy coupled with isotope labeling, we have mapped the structural evolution of the LOV2 domain of the flavin binding phototropin Avena sativa (AsLOV2) over 10 decades of time, reporting structural dynamics between 100 fs and 1 ms after optical excitation. The transient vibrational spectra contain contributions from both the flavin chromophore and the surrounding protein matrix. These contributions are resolved and assigned through the study of four different isotopically labeled samples. High signal-to-noise data permit the detailed analysis of kinetics associated with the light activated structural evolution. A pathway for the photocycle consistent with the data is proposed. The earliest events occur in the flavin binding pocket, where a subpicosecond perturbation of the protein matrix occurs. In this perturbed environment, the previously characterized reaction between triplet state isoalloxazine and an adjacent cysteine leads to formation of the adduct state; this step is shown to exhibit dispersive kinetics. This reaction promotes coupling of the optical excitation to successive time-dependent structural changes, initially in the β-sheet and then α-helix regions of the AsLOV2 domain, which ultimately gives rise to Jα-helix unfolding, yielding the signaling state. This model is tested through point mutagenesis, elucidating in particular the key mediating role played by Q513.
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Affiliation(s)
- Agnieszka A Gil
- Department of Chemistry, Stony Brook University , New York 11794-3400, United States
| | - Sergey P Laptenok
- School of Chemistry, University of East Anglia , Norwich, NR4 7TJ, U.K
| | - Jarrod B French
- Department of Chemistry, Stony Brook University , New York 11794-3400, United States
| | - James N Iuliano
- Department of Chemistry, Stony Brook University , New York 11794-3400, United States
| | - Andras Lukacs
- School of Chemistry, University of East Anglia , Norwich, NR4 7TJ, U.K.,Department of Biophysics, Medical School, University of Pecs , Szigeti ut 12, 7624 Pecs, Hungary
| | | | - Igor V Sazanovich
- Central Laser Facility, Research Complex at Harwell, Rutherford Appleton Laboratory , Didcot, Oxon OX11 0QX, U.K
| | - Gregory M Greetham
- Central Laser Facility, Research Complex at Harwell, Rutherford Appleton Laboratory , Didcot, Oxon OX11 0QX, U.K
| | - Adelbert Bacher
- Department Chemie, Technische Universität München , D-85747 Garching, Germany
| | - Boris Illarionov
- Institut für Biochemie und Lebensmittelchemie, Universität Hamburg , Grindelallee 117, D-20146 Hamburg, Germany
| | - Markus Fischer
- Institut für Biochemie und Lebensmittelchemie, Universität Hamburg , Grindelallee 117, D-20146 Hamburg, Germany
| | - Peter J Tonge
- Department of Chemistry, Stony Brook University , New York 11794-3400, United States
| | - Stephen R Meech
- School of Chemistry, University of East Anglia , Norwich, NR4 7TJ, U.K
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6
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Illarionov B, Zhu F, Eisenreich W, Bacher A, Weber S, Fischer M. Preparation of Flavocoenzyme Isotopologues by Biotransformation of Purines. J Org Chem 2015; 80:2539-44. [DOI: 10.1021/jo502480w] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Boris Illarionov
- Hamburg
School of Food Science, University of Hamburg, Grindelallee 117, 20146 Hamburg, Germany
| | - Feng Zhu
- Hamburg
School of Food Science, University of Hamburg, Grindelallee 117, 20146 Hamburg, Germany
| | - Wolfgang Eisenreich
- Department
Chemie, Technische Universität München, Lichtenbergstraße 4, 85748 München, Germany
| | - Adelbert Bacher
- Hamburg
School of Food Science, University of Hamburg, Grindelallee 117, 20146 Hamburg, Germany
- Department
Chemie, Technische Universität München, Lichtenbergstraße 4, 85748 München, Germany
| | - Stefan Weber
- Institut
für Physikalische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstraße
21, 79104 Freiburg, Germany
| | - Markus Fischer
- Hamburg
School of Food Science, University of Hamburg, Grindelallee 117, 20146 Hamburg, Germany
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7
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Bacher A, Illarionov B, Eisenreich W, Fischer M. A roadmap to the isotopolog space of flavocoenzymes. Methods Mol Biol 2014; 1146:65-78. [PMID: 24764088 DOI: 10.1007/978-1-4939-0452-5_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Flavocoenzymes with selective or universal stable isotope labeling are important tools for the investigation of flavoproteins using a variety of spectroscopic methods. Numerous selectively labeled flavin isotopologs can be generated by the combined application of chemical synthesis and in vitro biotransformation using commercially available enzymes and/or recombinant riboflavin biosynthesis enzymes. Notably, the complex reaction sequences can be rapidly carried out using enzyme-assisted one-pot reaction strategies.
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Affiliation(s)
- Adelbert Bacher
- Department of Chemistry, Organic Chemistry & Biochemistry, Technische Universität München, Lichtenbergstraße 4, 85748 Garching, Munich, Germany,
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8
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Kim RR, Illarionov B, Joshi M, Cushman M, Lee CY, Eisenreich W, Fischer M, Bacher A. Mechanistic insights on riboflavin synthase inspired by selective binding of the 6,7-dimethyl-8-ribityllumazine exomethylene anion. J Am Chem Soc 2010; 132:2983-90. [PMID: 20143812 PMCID: PMC2832097 DOI: 10.1021/ja908395r] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Riboflavin synthase catalyzes the transfer of a four-carbon fragment between two molecules of the substrate, 6,7-dimethyl-8-ribityllumazine, resulting in the formation of riboflavin and 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione. Earlier, a pentacyclic adduct formed from two substrate molecules was shown to be a catalytically competent intermediate, but the mechanism of its formation is still poorly understood. The present study shows that the recombinant N-terminal domain of riboflavin synthase from Escherichia coli interacts specifically with the exomethylene-type anion of 6,7-dimethyl-8-ribityllumazine but not with any of the tricyclic adduct-type anions that dominate the complex anion equilibrium in aqueous solution. Whereas these findings can be implemented into previously published mechanistic hypotheses, we also present a novel, hypothetical reaction sequence that starts with the transfer of a hydride ion from the 6,7-dimethyl-8-ribityllumazine exomethylene anion to an electroneutral 6,7-dimethyl-8-ribityllumazine molecule. The pair of dehydrolumazine and dihydrolumazine molecules resulting from this hydride transfer is proposed to undergo a 4 + 2 cycloaddition, affording the experimentally documented pentacyclic intermediate. In contrast to earlier mechanistic concepts requiring the participation of a nucleophilic agent, which is not supported by structural and mutagenesis data, the novel concept has no such requirement. Moreover, it requires fewer reaction steps and is consistent with all experimental data.
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Affiliation(s)
- Ryu-Ryun Kim
- Institute of Biochemistry and Food Chemistry, Food Chemistry Division, University of Hamburg, Grindelallee 117, D-20146 Hamburg, Germany
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9
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Crystal structures of the lumazine protein from Photobacterium kishitanii in complexes with the authentic chromophore, 6,7-dimethyl- 8-(1'-D-ribityl) lumazine, and its analogues, riboflavin and flavin mononucleotide, at high resolution. J Bacteriol 2010; 192:127-33. [PMID: 19854891 DOI: 10.1128/jb.01015-09] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Lumazine protein (LumP) is a fluorescent accessory protein having 6,7-dimethyl-8-(1'-d-ribityl) lumazine (DMRL) as its authentic chromophore. It modulates the emission of bacterial luciferase to shorter wavelengths with increasing luminous strength. To obtain structural information on the native structure as well as the interaction with bacterial luciferase, we have determined the crystal structures of LumP from Photobacterium kishitanii in complexes with DMRL and its analogues, riboflavin (RBF) and flavin mononucleotide (FMN), at resolutions of 2.00, 1.42, and 2.00 A. LumP consists of two beta barrels that have nearly identical folds, the N-terminal and C-terminal barrels. The structures of LumP in complex with all of the chromophores studied are all essentially identical, except around the chromophores. In all of the structures, the chromophore is tethered to the narrow cavity via many hydrogen bonds in the N-terminal domain. These are absent in the C-terminal domain. Hydrogen bonding in LumP-FMN is decreased in comparison with that in LumP-RBF because the phosphate moiety of FMN protrudes out of the narrow cavity. In LumP-DMRL, the side chain of Gln65 is close to the ring system, and a new water molecule that stabilizes the ligand is observed near Ser48. Therefore, DMRL packs more tightly in the ligand-binding site than RBF or FMN. A docking simulation of bacterial luciferase and LumP suggests that the chromophore is located close enough for direct energy transfer to occur. Moreover, the surface potentials around the ligand-binding sites of LumP and bacterial luciferase exhibit complementary charge distributions, which would have a significant effect on the interaction between LumP and luciferase.
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10
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Spanier B, Lasch K, Marsch S, Benner J, Liao W, Hu H, Kienberger H, Eisenreich W, Daniel H. How the intestinal peptide transporter PEPT-1 contributes to an obesity phenotype in Caenorhabditits elegans. PLoS One 2009; 4:e6279. [PMID: 19621081 PMCID: PMC2708923 DOI: 10.1371/journal.pone.0006279] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2009] [Accepted: 06/08/2009] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Amino acid absorption in the form of di- and tripeptides is mediated by the intestinal proton-coupled peptide transporter PEPT-1 (formally OPT-2) in Caenorhabditits elegans. Transporter-deficient animals (pept-1(lg601)) show impaired growth, slowed postembryonal development and major changes in amino acid status. PRINCIPAL FINDINGS Here we demonstrate that abolished intestinal peptide transport also leads to major metabolic alterations that culminate in a two fold increase in total body fat content. Feeding of C. elegans with [U-(13)C]-labelled E. coli revealed a decreased de novo synthesis of long-chain fatty acids in pept-1(lg601) and reduced levels of polyunsaturated fatty acids. mRNA profiling revealed increased transcript levels of enzymes/transporters needed for peroxisomal beta-oxidation and decreased levels for those required for fatty acid synthesis, elongation and desaturation. As a prime and most fundamental process that may account for the increased fat content in pept-1(lg601) we identified a highly accelerated absorption of free fatty acids from the bacterial food in the intestine. CONCLUSIONS The influx of free fatty acids into intestinal epithelial cells is strongly dependent on alterations in intracellular pH which is regulated by the interplay of PEPT-1 and the sodium-proton exchanger NHX-2. We here provide evidence for a central mechanism by which the PEPT-1/NHX-2 system strongly influences the in vivo fat content of C. elegans. Loss of PEPT-1 decreases intestinal proton influx leading to a higher uptake of free fatty acids with fat accumulation whereas loss of NHX-2 causes intracellular acidification by the PEPT-1 mediated proton/dipeptide symport with an almost abolished uptake of fatty acids and a lean phenotype.
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Affiliation(s)
- Britta Spanier
- Abteilung Biochemie, ZIEL Research Center of Nutrition and Food Sciences, Technische Universität München, Freising, Germany.
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11
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Eisenreich W, Joshi M, Illarionov B, Richter G, Römisch-Margl W, Müller F, Bacher A, Fischer M. 13C Isotopologue editing of FMN bound to phototropin domains. FEBS J 2007; 274:5876-90. [PMID: 17944933 DOI: 10.1111/j.1742-4658.2007.06111.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The plant blue light receptor phototropin comprises a protein kinase domain and two FMN-binding LOV domains (LOV1 and LOV2). Blue light irradiation of recombinant LOV domains is conducive to the addition of a cysteinyl thiolate group to carbon 4a of the FMN chromophore, and spontaneous cleavage of that photoadduct completes the photocycle of the receptor. The present study is based on (13)C NMR signal modulation observed after reconstitution of LOV domains of different origins with random libraries of (13)C-labeled FMN isotopologues. Using this approach, all (13)C signals of FMN bound to LOV1 and LOV2 domains of Avena sativa and to the LOV2 domain of the fern, Adiantum capillus-veneris, could be unequivocally assigned under dark and under blue light irradiation conditions. (13)C Chemical shifts of FMN are shown to be differently modulated by complexation with the LOV domains under study, indicating slight differences in the binding interactions of FMN and the apoproteins.
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Affiliation(s)
- Wolfgang Eisenreich
- Lehrstuhl für Organische Chemie und Biochemie, Technische Universität München, Garching, Germany.
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12
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Illarionov B, Lee CY, Bacher A, Fischer M, Eisenreich W. Random Isotopolog Libraries for Protein Perturbation Studies. 13C NMR Studies on Lumazine Protein of Photobacterium leiognathi. J Org Chem 2005; 70:9947-54. [PMID: 16292826 DOI: 10.1021/jo051662f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[graph: see text] Lumazine proteins of luminescent bacteria are paralogs of riboflavin synthase which are devoid of catalytic activity but bind the riboflavin synthase substrate, 6,7-dimethyl-8-ribityllumazine, with high affinity and are believed to serve as optical transponders for bioluminescence emission. Lumazine protein of Photobacterium leiognathi was expressed in a recombinant Escherichia coli host and was reconstituted with mixtures (random libraries) of 13C-labeled isotopologs of 6,7-dimethyl-8-ribityllumazine or riboflavin that had been prepared by biotransformation of [U-(13)C6]-, [1-(13)C1]-, [2-(13)C1]-, and [3-(13)C1]glucose. 13C NMR analysis of the protein/ligand complexes afforded the assignments of the 13C NMR chemical shifts for all carbon atoms of the protein-bound ligands by isotopolog abundance editing. The carbon atoms of the ribityl groups of both ligands studied were shifted up to 6 ppm upon binding to the protein. Chemical shift modulation of the side chain and chromophore carbon atoms due to protein/ligand interaction is discussed on the basis of the sequence similarity between lumazine protein and riboflavin synthase.
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Affiliation(s)
- Boris Illarionov
- Lehrstuhl für Organische Chemie und Biochemie, Technische Universität München, Lichtenbergstr. 4, D-85747 Garching, Germany
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13
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Illarionov B, Eisenreich W, Schramek N, Bacher A, Fischer M. Biosynthesis of vitamin B2: diastereomeric reaction intermediates of archaeal and non-archaeal riboflavin synthases. J Biol Chem 2005; 280:28541-6. [PMID: 15944152 DOI: 10.1074/jbc.m503093200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The dismutation of 6,7-dimethyl-8-ribityllumazine catalyzed by riboflavin synthase affords riboflavin and 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione. A pentacyclic adduct of two 6,7-dimethyl-8-ribityllumazines has been identified earlier as a catalytically competent reaction intermediate of the Escherichia coli enzyme. Acid quenching of reaction mixtures of riboflavin synthase of Methanococcus jannaschii, a paralog of 6,7-dimethyl-8-ribityllumazine synthase devoid of similarity with riboflavin synthases of eubacteria and eukaryotes, afforded a compound whose optical absorption and NMR spectra resemble that of the pentacyclic E. coli riboflavin synthase intermediate, whereas the circular dichroism spectra of the two compounds have similar envelopes but opposite signs. Each of the compounds could serve as a catalytically competent intermediate for the enzyme by which it was produced, but not vice versa. All available data indicate that the respective pentacyclic intermediates of the M. jannaschii and E. coli enzymes are diastereomers.
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Affiliation(s)
- Boris Illarionov
- Lehrstuhl für Organische Chemie und Biochemie, Technische Universität München, Lichtenbergstrasse 4, D-85747 Garching, Germany
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