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Meyer KAE, Garand E. The impact of solvation on the structure and electric field strength in Li +GlyGly complexes. Phys Chem Chem Phys 2024; 26:12406-12421. [PMID: 38623633 DOI: 10.1039/d3cp06264c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/17/2024]
Abstract
To scrutinise the impact of electric fields on the structure and vibrations of biomolecules in the presence of water, we study the sequential solvation of lithium diglycine up to three water molecules with cryogenic infrared action spectroscopy. Conformer-specific IR-IR spectroscopy and H2O/D2O isotopic substitution experiments provide most of the information required to decipher the structure of the observed conformers. Additional confirmation is provided by scaled harmonic vibrational frequency calculations using MP2 and DFT. The first water molecule is shown to bind to the Li+ ion, which weakens the electric field experienced by the peptide and as a consequence, also the strength of an internal NH⋯NH2 hydrogen bond in the diglycine backbone. The strength of this hydrogen bond decreases approximately linearly with the number of water molecules as a result of the decreasing electric field strength and coincides with an increase in the number of conformers observed in our spectra. The addition of two water molecules is already sufficient to change the preferred conformation of the peptide backbone, allowing for Li+ coordination to the lone pair of the terminal amine group.
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Affiliation(s)
- Katharina A E Meyer
- University of Wisconsin-Madison, Department of Chemistry, 1101 University Ave, Madison, WI 53706, USA.
| | - Etienne Garand
- University of Wisconsin-Madison, Department of Chemistry, 1101 University Ave, Madison, WI 53706, USA.
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Ball R, Jackson JA, Simeon T, Schatz GC, Shafer JC, Anna JM. Vibrational anisotropy decay resolves rare earth binding induced conformational change in DTPA. Phys Chem Chem Phys 2024; 26:10078-10090. [PMID: 38482833 DOI: 10.1039/d4cp00673a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/28/2024]
Abstract
Elucidating the relationship between metal-ligand interactions and the associated conformational change of the ligand is critical for understanding the separation of lanthanides via ion binding. Here we examine DTPA, a multidentate ligand that binds lanthanides, in its free and metal bound conformations using ultrafast polarization dependent vibrational spectroscopy. The polarization dependent pump-probe spectra were analyzed to extract the isotropic and anisotropic response of DTPA's carbonyl groups in the 1550-1650 cm-1 spectral region. The isotropic response reports on the population relaxation of the carbonyl stretching modes. We find that the isotropic response is influenced by the identity of the metal ion. The anisotropy decay of the carbonyl stretching modes reveals a faster decay in the lanthanide-DTPA complexes than in the free DTPA ligand. We attribute the anisotropy decay to energy transfer among the different carbonyl sites - where the conformational change results in an increased coupling between the carbonyl sites of metal-bound DTPA complexes. DFT calculations and theoretical simulations of energy transfer suggest that the carbonyl sites are more strongly coupled in the metal-bound conformations compared to the free DTPA. The stronger coupling in the metal bound DTPA conformation leads to efficient energy transfer among the different carbonyl sites. Comparing the rate of anisotropy decay across the series of metal bound DTPA complexes we find that the anisotropy is sensitive to the charge density of the central metal ion, and thus can serve as a molecular scale reporter for lanthanide ion binding.
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Affiliation(s)
- Ranadeb Ball
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Jessica A Jackson
- Department of Chemistry, Colorado School of Mines, Golden, Colorado 80401, USA
| | - Tomekia Simeon
- School of STEM, Dillard University, New Orleans, Louisiana 70122, USA
| | - George C Schatz
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, USA
| | - Jenifer C Shafer
- Department of Chemistry, Colorado School of Mines, Golden, Colorado 80401, USA
| | - Jessica M Anna
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- Department of Chemistry, University of Pittsburgh, Pennsylvania 15260, USA.
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Śmiłowicz D, Eisenberg S, LaForest R, Whetter J, Hariharan A, Bordenca J, Johnson CJ, Boros E. Metal-Mediated, Autolytic Amide Bond Cleavage: A Strategy for the Selective, Metal Complexation-Catalyzed, Controlled Release of Metallodrugs. J Am Chem Soc 2023; 145:16261-16270. [PMID: 37434328 PMCID: PMC10530410 DOI: 10.1021/jacs.3c05492] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/13/2023]
Abstract
Activation of metalloprodrugs or prodrug activation using transition metal catalysts represents emerging strategies for drug development; however, they are frequently hampered by poor spatiotemporal control and limited catalytic turnover. Here, we demonstrate that metal complex-mediated, autolytic release of active metallodrugs can be successfully employed to prepare clinical grade (radio-)pharmaceuticals. Optimization of the Lewis-acidic metal ion, chelate, amino acid linker, and biological targeting vector provides means to release peptide-based (radio-)metallopharmaceuticals in solution and from the solid phase using metal-mediated, autolytic amide bond cleavage (MMAAC). Our findings indicate that coordinative polarization of an amide bond by strong, trivalent Lewis acids such as Ga3+ and Sc3+ adjacent to serine results in the N, O acyl shift and hydrolysis of the corresponding ester without dissociation of the corresponding metal complex. Compound [68Ga]Ga-10, incorporating a cleavable and noncleavable functionalization, was used to demonstrate that only the amide bond-adjacent serine effectively triggered hydrolysis in solution and from the solid phase. The corresponding solid-phase released compound [68Ga]Ga-8 demonstrated superior in vivo performance in a mouse tumor model compared to [68Ga]Ga-8 produced using conventional, solution-phase radiolabeling. A second proof-of-concept system, [67Ga]Ga-17A (serine-linked) and [67Ga]Ga-17B (glycine-linked) binding to serum albumin via the incorporated ibuprofen moiety, was also synthesized. These constructs demonstrated that complete hydrolysis of the corresponding [68Ga]Ga-NOTA complex from [67Ga]Ga-17A can be achieved in naïve mice within 12 h, as traceable in urine and blood metabolites. The glycine-linked control [68Ga]Ga-17B remained intact. Conclusively, MMAAC provides an attractive tool for selective, thermal, and metal ion-mediated control of metallodrug activation compatible with biological conditions.
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Affiliation(s)
- Dariusz Śmiłowicz
- Department of Chemistry, Stony Brook University, 100 Nicolls Road, Stony Brook, New York 11794, United States
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Shawn Eisenberg
- Department of Chemistry, Stony Brook University, 100 Nicolls Road, Stony Brook, New York 11794, United States
| | - Rochelle LaForest
- Department of Chemistry, Stony Brook University, 100 Nicolls Road, Stony Brook, New York 11794, United States
| | - Jennifer Whetter
- Department of Chemistry, Stony Brook University, 100 Nicolls Road, Stony Brook, New York 11794, United States
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Annapoorani Hariharan
- Department of Chemistry, Stony Brook University, 100 Nicolls Road, Stony Brook, New York 11794, United States
| | - Jake Bordenca
- Department of Chemistry, Stony Brook University, 100 Nicolls Road, Stony Brook, New York 11794, United States
| | - Christopher J Johnson
- Department of Chemistry, Stony Brook University, 100 Nicolls Road, Stony Brook, New York 11794, United States
| | - Eszter Boros
- Department of Chemistry, Stony Brook University, 100 Nicolls Road, Stony Brook, New York 11794, United States
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
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Foreman MM, Alessio M, Krylov AI, Weber JM. Influence of Transition Metal Electron Configuration on the Structure of Metal-EDTA Complexes. J Phys Chem A 2023; 127:2258-2264. [PMID: 36877889 DOI: 10.1021/acs.jpca.2c07996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
Abstract
The vibrational spectra of cold complexes of ethylenediaminetetraacetic acid (EDTA) with transition metal dications in vacuo show how the electronic structure of the metal provides a geometric template for interaction with the functional groups of the binding pocket. The OCO stretching modes of the carboxylate groups of EDTA serve as structural probes, informing on the spin state of the ion as well as the coordination number in the complex. The results highlight the flexibility of EDTA in accepting a large range of metal cations in its binding site.
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Affiliation(s)
- Madison M Foreman
- JILA and Department of Chemistry, University of Colorado at Boulder, UCB 440, Boulder, Colorado 80309, United States
| | - Maristella Alessio
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
| | - Anna I Krylov
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
| | - J Mathias Weber
- JILA and Department of Chemistry, University of Colorado at Boulder, UCB 440, Boulder, Colorado 80309, United States
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