1
|
Alasadi EA, Choi W, Chen X, Cotruvo JA, Baiz CR. Lanmodulin's EF 2-3 Domain: Insights from Infrared Spectroscopy and Simulations. ACS Chem Biol 2024; 19:1056-1065. [PMID: 38620063 DOI: 10.1021/acschembio.3c00789] [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] [Indexed: 04/17/2024]
Abstract
Lanmodulins are small, ∼110-residue proteins with four EF-hand motifs that demonstrate a picomolar affinity for lanthanide ions, making them efficient in the recovery and separation of these technologically important metals. In this study, we examine the thermodynamic and structural complexities of lanthanide ion binding to a 41-residue domain, EF 2-3, that constitutes the two highest-affinity metal-binding sites in the lanmodulin protein from Methylorubrum extorquens. Using a combination of circular dichroism (CD) spectroscopy, isothermal titration calorimetry (ITC), two-dimensional infrared (2D IR) spectroscopy, and molecular dynamics (MD) simulations, we characterize the metal binding capabilities of EF 2-3. ITC demonstrates that binding occurs between peptide and lanthanides with conditional dissociation constants (Kd) in the range 20-30 μM, with no significant differences in the Kd values for La3+, Eu3+, and Tb3+ at pH 7.4. In addition, CD spectroscopy suggests that only one binding site of EF 2-3 undergoes a significant conformational change in the presence of lanthanides. 2D IR spectroscopy demonstrates the presence of both mono- and bidentate binding configurations in EF 2-3 with all three lanthanides. MD simulations, supported by Eu3+ luminescence measurements, explore these results, suggesting a competition between water-lanthanide and carboxylate-lanthanide interactions in the EF 2-3 domain. These results underscore the role of the core helical bundle of the protein architecture in influencing binding affinities and communication between the metal-binding sites in the full-length protein.
Collapse
Affiliation(s)
- Eman A Alasadi
- Department of Chemistry, University of Texas at Austin, 105 E 24th St. A5300, Austin, Texas 78712, United States
| | - Wonseok Choi
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Xiaobing Chen
- Department of Chemistry, University of Texas at Austin, 105 E 24th St. A5300, Austin, Texas 78712, United States
| | - Joseph A Cotruvo
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Carlos R Baiz
- Department of Chemistry, University of Texas at Austin, 105 E 24th St. A5300, Austin, Texas 78712, United States
| |
Collapse
|
2
|
Marlina D, Müllers Y, Glebe U, Kumke MU. Spectroscopic characterization of europium binding to a calmodulin-EF4 hand peptide-polymer conjugate. RSC Adv 2024; 14:14091-14099. [PMID: 38686292 PMCID: PMC11056824 DOI: 10.1039/d4ra01505c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Accepted: 04/24/2024] [Indexed: 05/02/2024] Open
Abstract
The emergence of biological ligand as an alternative to chemical ligands enables a sustainable lanthanide extraction route. In this study, a peptide originating from the loop of domain 4 calmodulin (EF4) was synthesized and the interaction with europium ions was monitored using time resolved laser fluorescence spectroscopy (TRLFS). Despite being retracted from its full protein structure, the twelve amino acids of calmodulin-EF4 showed binding to europium. Europium-peptide complex formation was evident by an increase in decay time from 110 to 187 μs. The spectra of europium bound to peptide can be easily distinguished from the free europium ion as the 5D0 → 7F2 peak intensifies. When europium bound to the peptide-polymer conjugate, the decay time was further increased to 259 μs. This suggests that lanthanide binding can be enhanced by immobilizing the short peptide into a polymer matrix. The europium-peptide/conjugate bond was reversible, triggered by pH, promoting peptide reusability. Due to the fact that the study was conducted exclusively in water, it suggests minimal use of chemicals is possible while maintaining peptide affinity. This makes the calmodulin-EF4 peptide an ideal candidate as biological ligand. This study lays the groundwork for developing a peptide-based filter material for lanthanide separation.
Collapse
Affiliation(s)
- Dini Marlina
- University of Potsdam, Institute of Chemistry, Optical Sensing and Spectroscopy Karl-Liebknecht-Str. 24-25 14476 Potsdam-Golm Germany
| | - Yannic Müllers
- University of Potsdam, Institute of Chemistry, Polymer Materials and Polymer Technologies Karl-Liebknecht-Str. 24-25 14476 Potsdam-Golm Germany
- Fraunhofer Institute for Applied Polymer Research IAP Geiselbergstr. 69 14476 Potsdam-Golm Germany
| | - Ulrich Glebe
- University of Potsdam, Institute of Chemistry, Polymer Materials and Polymer Technologies Karl-Liebknecht-Str. 24-25 14476 Potsdam-Golm Germany
- Fraunhofer Institute for Applied Polymer Research IAP Geiselbergstr. 69 14476 Potsdam-Golm Germany
| | - Michael U Kumke
- University of Potsdam, Institute of Chemistry, Optical Sensing and Spectroscopy Karl-Liebknecht-Str. 24-25 14476 Potsdam-Golm Germany
| |
Collapse
|
3
|
Kastenhofer J, Spadiut O, Papangelakis VG, Allen DG. Roles of pH and phosphate in rare earth element biosorption with living acidophilic microalgae. Appl Microbiol Biotechnol 2024; 108:262. [PMID: 38483568 PMCID: PMC10940408 DOI: 10.1007/s00253-024-13068-8] [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: 10/25/2023] [Revised: 02/01/2024] [Accepted: 02/11/2024] [Indexed: 03/17/2024]
Abstract
The increasing demand for rare earth elements (REEs) has spurred interest in the development of recovery methods from aqueous waste streams. Acidophilic microalgae have gained attention for REE biosorption as they can withstand high concentrations of transition metals and do not require added organic carbon to grow, potentially allowing simultaneous sorption and self-replication of the sorbent. Here, we assessed the potential of Galdieria sulphuraria for REE biosorption under acidic, nutrient-replete conditions from solutions containing ≤ 15 ppm REEs. Sorption at pH 1.5-2.5 (the growth optimum of G. sulphuraria) was poor but improved up to 24-fold at pH 5.0 in phosphate-free conditions. Metabolic activity had a negative impact on REE sorption, additionally challenging the feasibility of REE biosorption under ideal growth conditions for acidophiles. We further examined the possibility of REE biosorption in the presence of phosphate for biomass growth at elevated pH (pH ≥ 2.5) by assessing aqueous La concentrations in various culture media. Three days after adding La into the media, dissolved La concentrations were up to three orders of magnitude higher than solubility predictions due to supersaturation, though LaPO4 precipitation occurred under all conditions when seed was added. We concluded that biosorption should occur separately from biomass growth to avoid REE phosphate precipitation. Furthermore, we demonstrated the importance of proper control experiments in biosorption studies to assess potential interactions between REEs and matrix ions such as phosphates. KEY POINTS: • REE biosorption with G. sulphuraria increases significantly when raising pH to 5 • Phosphate for biosorbent growth has to be supplied separately from biosorption • Biosorption studies have to assess potential matrix effects on REE behavior.
Collapse
Affiliation(s)
- Jens Kastenhofer
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON, M5S 3E5, Canada
| | - Oliver Spadiut
- Institute of Chemical, Environmental and Bioscience Engineering, Research Division Biochemical Engineering, Research Group Integrated Bioprocess Development, TU Vienna, Gumpendorfer Straße 1a, 1060, Vienna, Austria
| | - Vladimiros G Papangelakis
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON, M5S 3E5, Canada
| | - D Grant Allen
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON, M5S 3E5, Canada.
| |
Collapse
|
4
|
Yon M, Esmangard L, Enel M, Desmoulin F, Pestourie C, Leygue N, Mingotaud C, Galaup C, Marty JD. Simple hybrid polymeric nanostructures encapsulating macro-cyclic Gd/Eu based complexes: luminescence properties and application as MRI contrast agent. NANOSCALE 2024; 16:3729-3737. [PMID: 38294340 DOI: 10.1039/d3nr06162k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Lanthanide-based macrocycles are successfully incorporated into hybrid polyionic complexes, formed by adding a mixture of zirconium ions to a solution of a double-hydrophilic block copolymer. The resulting nanoobjects with an average radius of approximately 10-15 nm present good colloidal and chemical stability in physiological media even in the presence of competing ions such as phosphate or calcium ions. The final optical and magnetic properties of these objects benefit from both their colloidal nature and the specific properties of the complexes. Hence these new nanocarriers exhibit enhanced T1 MRI contrast, when administered intravenously to mice.
Collapse
Affiliation(s)
- Marjorie Yon
- Laboratoire Softmat, University of Toulouse, CNRS UMR 5623, University Toulouse III - Paul Sabatier, France, 118, route de Narbonne, 31062 Toulouse Cedex 9, France.
| | - Lucie Esmangard
- Laboratoire Softmat, University of Toulouse, CNRS UMR 5623, University Toulouse III - Paul Sabatier, France, 118, route de Narbonne, 31062 Toulouse Cedex 9, France.
| | - Morgane Enel
- Laboratoire SPCMIB, CNRS UMR 5068, University of Toulouse, University Toulouse III - Paul Sabatier 118, route de Narbonne 31062, Toulouse Cedex 9, France.
| | - Franck Desmoulin
- Toulouse NeuroImaging Center (ToNIC), Inserm, University of Toulouse - Paul Sabatier, Toulouse, France
- CREFRE-Anexplo, University of Toulouse, Inserm, UT3, ENVT, Toulouse, France
| | - Carine Pestourie
- CREFRE-Anexplo, University of Toulouse, Inserm, UT3, ENVT, Toulouse, France
| | - Nadine Leygue
- Laboratoire SPCMIB, CNRS UMR 5068, University of Toulouse, University Toulouse III - Paul Sabatier 118, route de Narbonne 31062, Toulouse Cedex 9, France.
| | - Christophe Mingotaud
- Laboratoire Softmat, University of Toulouse, CNRS UMR 5623, University Toulouse III - Paul Sabatier, France, 118, route de Narbonne, 31062 Toulouse Cedex 9, France.
| | - Chantal Galaup
- Laboratoire SPCMIB, CNRS UMR 5068, University of Toulouse, University Toulouse III - Paul Sabatier 118, route de Narbonne 31062, Toulouse Cedex 9, France.
| | - Jean-Daniel Marty
- Laboratoire Softmat, University of Toulouse, CNRS UMR 5623, University Toulouse III - Paul Sabatier, France, 118, route de Narbonne, 31062 Toulouse Cedex 9, France.
| |
Collapse
|
5
|
Martinon TLM, Pierre VC. Luminescent lanthanide probes for cations and anions: Promises, compromises, and caveats. Curr Opin Chem Biol 2023; 76:102374. [PMID: 37517109 PMCID: PMC10529829 DOI: 10.1016/j.cbpa.2023.102374] [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: 03/12/2023] [Revised: 06/28/2023] [Accepted: 07/01/2023] [Indexed: 08/01/2023]
Abstract
The long luminescence lifetimes and sharp emission bands of luminescent lanthanide complexes have long been recognized as invaluable strengths for sensing and imaging in complex aqueous biological or environmental media. Herein we discuss the recent developments of these probes for sensing metal ions and, increasingly, anions. Underappreciated in the field, buffers and metal hydrolysis influence the response of many responsive lanthanide probes. The inherent complexities arising from these interactions are further discussed.
Collapse
Affiliation(s)
- Thibaut L M Martinon
- Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis MN 55455, USA
| | - Valérie C Pierre
- Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis MN 55455, USA.
| |
Collapse
|
6
|
Friedrich S, Sieber C, Drobot B, Tsushima S, Barkleit A, Schmeide K, Stumpf T, Kretzschmar J. Eu(III) and Cm(III) Complexation by the Aminocarboxylates NTA, EDTA, and EGTA Studied with NMR, TRLFS, and ITC-An Improved Approach to More Robust Thermodynamics. Molecules 2023; 28:4881. [PMID: 37375436 DOI: 10.3390/molecules28124881] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 06/12/2023] [Accepted: 06/16/2023] [Indexed: 06/29/2023] Open
Abstract
The complex formation of Eu(III) and Cm(III) was studied via tetradentate, hexadentate, and octadentate coordinating ligands of the aminopolycarboxylate family, viz., nitrilotriacetate (NTA3-), ethylenediaminetetraacetate (EDTA4-), and ethylene glycol-bis(2-aminoethyl ether)-N,N,N',N'-tetraacetate (EGTA4-), respectively. Based on the complexones' pKa values obtained from 1H nuclear magnetic resonance (NMR) spectroscopic pH titration, complex formation constants were determined by means of the parallel-factor-analysis-assisted evaluation of Eu(III) and Cm(III) time-resolved laser-induced fluorescence spectroscopy (TRLFS). This was complemented by isothermal titration calorimetry (ITC), providing the enthalpy and entropy of the complex formation. This allowed us to obtain genuine species along with their molecular structures and corresponding reliable thermodynamic data. The three investigated complexones formed 1:1 complexes with both Eu(III) and Cm(III). Besides the established Eu(III)-NTA 1:1 and 1:2 complexes, we observed, for the first time, the existence of a Eu(III)-NTA 2:2 complex of millimolar metal and ligand concentrations. Demonstrated for thermodynamic studies on Eu(III) and Cm(III) interaction with complexones, the utilized approach is commonly applicable to many other metal-ligand systems, even to high-affinity ligands.
Collapse
Affiliation(s)
- Sebastian Friedrich
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, 01328 Dresden, Germany
| | - Claudia Sieber
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, 01328 Dresden, Germany
| | - Björn Drobot
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, 01328 Dresden, Germany
| | - Satoru Tsushima
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, 01328 Dresden, Germany
- International Research Frontiers Initiative, Institute of Innovative Research, Tokyo Institute of Technology, Meguro, Tokyo 152-8550, Japan
| | - Astrid Barkleit
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, 01328 Dresden, Germany
| | - Katja Schmeide
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, 01328 Dresden, Germany
| | - Thorsten Stumpf
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, 01328 Dresden, Germany
| | - Jerome Kretzschmar
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, 01328 Dresden, Germany
| |
Collapse
|
7
|
Martinon TLM, Ramakrishnam Raju MV, Pierre VC. Kinetically Inert Macrocyclic Europium(III) Receptors for Phosphate. Inorg Chem 2023. [PMID: 37339454 PMCID: PMC10389169 DOI: 10.1021/acs.inorgchem.2c03833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/22/2023]
Abstract
The significant role that phosphate plays in environmental water pollution and biomedical conditions such as hyperphosphatemia highlights the need to develop robust receptors that can sequester the anion effectively and selectively from complex aqueous media. Toward that goal, four macrocyclic tris-bidentate 1,2-hydroxypyridonate (HOPO) europium(III) complexes containing either a cyclen, cyclam, TACN, or TACD ligand cap were synthesized and evaluated as phosphate receptors. The solubility of EuIII-TACD-HOPO in water was insufficient for luminescent studies. Whereas EuIII-cyclen-HOPO is eight coordinate with two inner-sphere water molecules, both EuIII-cyclam-HOPO and EuIII-TACN-HOPO are nine coordinate with three inner-sphere water molecules, suggesting that the two coordination states are very close in energy. As observed previously with linear analogues of tripodal HOPO complexes, there is no relationship between the number of inner-sphere water molecules and the affinity of the complex for phosphate. Whereas all three complexes do bind phosphate, EuIII-cyclen-HOPO has the highest affinity for phosphate with the anion displacing both of its inner-sphere water molecules. On the other hand, only one or two of the three inner-sphere water molecules of EuIII-TACN-HOPO and EuIII-cyclam-HOPO are displaced by phosphate, respectively. All three complexes are highly selective for phosphate over other anions, including arsenate. All three complexes are highly stable. EuIII-cyclen-HOPO and, to a lesser extent, EuIII-TACN-HOPO are more kinetically inert than the linear EuIII-Ser-HOPO. EuIII-cyclam-HOPO, on the other hand, is not. This study highlights the significant effect that minor changes in the ligand cap can have on both the ligand exchange rate and affinity for phosphate of tripodal 1,2-dihydroxypyridinonate complexes.
Collapse
Affiliation(s)
- Thibaut L M Martinon
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | | | - Valérie C Pierre
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| |
Collapse
|
8
|
Nielsen LG, Sørensen TJ. Effect of buffers and pH in antenna sensitized Eu(III) luminescence. Methods Appl Fluoresc 2023; 11. [PMID: 36696692 DOI: 10.1088/2050-6120/acb63a] [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: 11/14/2022] [Accepted: 01/25/2023] [Indexed: 01/26/2023]
Abstract
The photophysics of a europium(III) complex of 1,4,7,10-tetraazacycododecane-1,4,7-triacetic acid-10-(2-methylene)-1-azathioxanthone was investigated in three buffer systems and at three pH values. The buffers-phosphate buffered saline (PBS), 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES), and universal buffer (UB)-had no effect on the europium luminescence, but a lower overall emission intensity was determined in HEPES. It was found that this was due to quenching of the 1-azathioxanthone first excited singlet state by HEPES. The effect of pH on the photophysics of the complex was found to be minimal, and protonation of the pyridine nitrogen was found to be irrelevant. Even so, pH was shown to change the intensity ratio between 1-azathioxanthone fluorescence and europium luminescence. It was concluded that the full photophysics of a potential molecular probe should be investigated to achieve the best possible results in any application.
Collapse
Affiliation(s)
- Lea Gundorff Nielsen
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, København Ø, Denmark
| | - Thomas Just Sørensen
- Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, København Ø, Denmark
| |
Collapse
|
9
|
Danaf NA, Kretzschmar J, Jahn B, Singer H, Pol A, Op den Camp HJM, Steudtner R, Lamb DC, Drobot B, Daumann LJ. Studies of pyrroloquinoline quinone species in solution and in lanthanide-dependent methanol dehydrogenases. Phys Chem Chem Phys 2022; 24:15397-15405. [PMID: 35704886 DOI: 10.1039/d2cp00311b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Pyrroloquinoline quinone (PQQ) is a redox cofactor in calcium- and lanthanide-dependent alcohol dehydrogenases that has been known and studied for over 40 years. Despite its long history, many questions regarding its fluorescence properties, speciation in solution and in the active site of alcohol dehydrogenase remain open. Here we investigate the effects of pH and temperature on the distribution of different PQQ species (H3PQQ to PQQ3- in addition to water adducts and in complex with lanthanides) with NMR and UV-Vis spectroscopy as well as time-resolved laser-induced fluorescence spectroscopy (TRLFS). Using a europium derivative from a new, recently-discovered class of lanthanide-dependent methanol dehydrogenase (MDH) enzymes, we utilized two techniques to monitor Ln binding to the active sites of these enzymes. Employing TRLFS, we were able to follow Eu(III) binding directly to the active site of MDH using its luminescence and could quantify three Eu(III) states: Eu(III) in the active site of MDH, but also in solution as PQQ-bound Eu(III) and in the aquo-ion form. Additionally, we used the antenna effect to study PQQ and simultaneously Eu(III) in the active site.
Collapse
Affiliation(s)
- Nader Al Danaf
- Department of Chemistry, Ludwig-Maximilians-University Munich, Butenandtstraße 5 - 13, 81377 München, Germany. .,Center for NanoScience, Ludwig-Maximilians-University Munich, Geschwister-Scholl Platz 1, 80539 München, Germany
| | - Jerome Kretzschmar
- Institute of Resource Ecology, Helmholtz-Zentrum Dresden-Rossendorf e.V., Bautzner Landstraße 400, 01328 Dresden, Germany.
| | - Berenice Jahn
- Department of Chemistry, Ludwig-Maximilians-University Munich, Butenandtstraße 5 - 13, 81377 München, Germany.
| | - Helena Singer
- Department of Chemistry, Ludwig-Maximilians-University Munich, Butenandtstraße 5 - 13, 81377 München, Germany.
| | - Arjan Pol
- Department of Microbiology, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Huub J M Op den Camp
- Department of Microbiology, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Robin Steudtner
- Institute of Resource Ecology, Helmholtz-Zentrum Dresden-Rossendorf e.V., Bautzner Landstraße 400, 01328 Dresden, Germany.
| | - Don C Lamb
- Department of Chemistry, Ludwig-Maximilians-University Munich, Butenandtstraße 5 - 13, 81377 München, Germany. .,Center for NanoScience, Ludwig-Maximilians-University Munich, Geschwister-Scholl Platz 1, 80539 München, Germany
| | - Björn Drobot
- Institute of Resource Ecology, Helmholtz-Zentrum Dresden-Rossendorf e.V., Bautzner Landstraße 400, 01328 Dresden, Germany.
| | - Lena J Daumann
- Department of Chemistry, Ludwig-Maximilians-University Munich, Butenandtstraße 5 - 13, 81377 München, Germany.
| |
Collapse
|