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Khoury F, Su Z, Banta S. Rare Earth Element Binding and Recovery by a Beta Roll-Forming RTX Domain. Inorg Chem 2024; 63:13223-13230. [PMID: 38986039 DOI: 10.1021/acs.inorgchem.4c00420] [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: 07/12/2024]
Abstract
The Block V of the RTX domain of the adenylate cyclase protein from Bordetella pertussis is disordered, and upon binding eight calcium ions, it folds into a beta roll domain with a C-terminal capping group. Due to their similar ionic radii and coordination geometries, trivalent lanthanide ions have been used to probe and identify calcium-binding sites in many proteins. Here, we report using a FRET-based assay that the RTX domain can bind rare earth elements (REEs) with higher affinities than calcium. The apparent disassociation constants for lanthanide ions ranged from 20 to 75 μM, which are an order of magnitude higher than the affinity for calcium, with a higher selectivity toward heavy REEs over light REEs. Most proteins release bound ions at mildly acidic conditions (pH 5-6), and the high affinity REE-binding lanmodulin protein can bind 3-4 REE ions at pH as low as ∼2.5. Circular dichroism (CD) spectra of the RTX domain demonstrate pH-induced folding of the beta roll domain in the absence of ions, indicating that protonation of key amino acids enables structure formation in low pH solutions. The beta roll domain coordinates up to four ions in extreme pH conditions (pH < 1), as determined by equilibrium ultrafiltration experiments. Finally, to demonstrate a potential application of the RTX domain, REE ions (Nd3+ and Dy3+) were recovered from other non-REEs (Fe2+ and Co2+) in a NdFeB magnet simulant solution (at pH 6).
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Affiliation(s)
- Farid Khoury
- Department of Chemical Engineering, Columbia University, New York, New York 10027, United States
| | - Zihang Su
- Department of Chemical Engineering, Columbia University, New York, New York 10027, United States
| | - Scott Banta
- Department of Chemical Engineering, Columbia University, New York, New York 10027, United States
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Yang Y, Liu Y, Tu D, Chen M, Zhang Y, Gao H, Chen X. Tumor-Microenvironment-Responsive Biodegradable Nanoagents Based on Lanthanide Nucleotide Self-Assemblies toward Precise Cancer Therapy. Angew Chem Int Ed Engl 2022; 61:e202116983. [PMID: 35084798 DOI: 10.1002/anie.202116983] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Indexed: 12/25/2022]
Abstract
Stimuli-responsive nanoagents, which simultaneously satisfy normal tissue clearance and tumor-specific responsive treatment, are highly attractive for precise cancer theranostics. Herein, we develop a unique template-induced self-assembly strategy for the exquisitely controlled synthesis of self-assembled lanthanide (Ln3+ ) nucleotide nanoparticles (LNNPs) with amorphous structure and tunable size from sub-5 nm to 105 nm. By virtue of the low-temperature (10 K) and high-resolution spectroscopy, the local site symmetry of Ln3+ in LNNPs is unraveled for the first time. The proposed LNNPs are further demonstrated to possess the ability for highly efficient loading and tumor-microenvironment-responsive release of doxorubicin. Particularly, sub-5 nm LNNPs not only exhibit excellent biocompatibility and predominant renal-clearance performance, but also enable efficient tumor retention. These findings reveal the great potential of LNNPs as a new generation of therapeutic platform to overcome the dilemma between efficient therapy and long-term toxicity of nanoagents for future clinical applications.
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Affiliation(s)
- Yingjie Yang
- CAS Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian Key Laboratory of Nanomaterials, and State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian, 350002, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yan Liu
- CAS Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian Key Laboratory of Nanomaterials, and State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian, 350002, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Datao Tu
- CAS Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian Key Laboratory of Nanomaterials, and State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian, 350002, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Mingmao Chen
- College of Biological Science and Engineering, Fuzhou University, Fuzhou, Fujian, 350108, China
| | - Yunqin Zhang
- CAS Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian Key Laboratory of Nanomaterials, and State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian, 350002, China
| | - Hang Gao
- CAS Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian Key Laboratory of Nanomaterials, and State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian, 350002, China
| | - Xueyuan Chen
- CAS Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian Key Laboratory of Nanomaterials, and State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian, 350002, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
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Yang Y, Liu Y, Tu D, Chen M, Zhang Y, Gao H, Chen X. Tumor‐Microenvironment‐Responsive Biodegradable Nanoagents Based on Lanthanide Nucleotide Self‐Assemblies toward Precise Cancer Therapy. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202116983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Yingjie Yang
- Chinese Academy of Sciences Fujian Institute of Research on the Structure of Matter CAS Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian Key Laboratory of Nanomaterials, and State Key Laboratory of Structural Chemistry CHINA
| | - Yan Liu
- Chinese Academy of Sciences Fujian Institute of Research on the Structure of Matter CAS Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian Key Laboratory of Nanomaterials, and State Key Laboratory of Structural Chemistry 350002 Fuzhou CHINA
| | - Datao Tu
- Chinese Academy of Sciences Fujian Institute of Research on the Structure of Matter CAS Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian Key Laboratory of Nanomaterials, and State Key Laboratory of Structural Chemistry CHINA
| | - Mingmao Chen
- Fuzhou University College of Biological Science and Engineering CHINA
| | - Yunqin Zhang
- Chinese Academy of Sciences Fujian Institute of Research on the Structure of Matter CAS Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian Key Laboratory of Nanomaterials, and State Key Laboratory of Structural Chemistry CHINA
| | - Hang Gao
- Chinese Academy of Sciences Fujian Institute of Research on the Structure of Matter CAS Key Laboratory of Design and Assembly of Functional Nanostructures, Fujian Key Laboratory of Nanomaterials, and State Key Laboratory of Structural Chemistry CHINA
| | - Xueyuan Chen
- Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences 155 West Yangqiao Road Fuzhou CHINA
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Gao F, Thornley BS, Tressler CM, Naduthambi D, Zondlo NJ. Phosphorylation-dependent protein design: design of a minimal protein kinase-inducible domain. Org Biomol Chem 2019; 17:3984-3995. [PMID: 30942803 PMCID: PMC6668337 DOI: 10.1039/c9ob00502a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Protein kinases and phosphatases modulate protein structure and function, which in turn regulate cellular activities. The development of novel proteins and protein motifs that are responsive to protein phosphorylation provides new ways to probe the functions of individual protein kinases and the intracellular effects of their activation and downregulation. Herein we develop a minimal motif that is responsive to protein phosphorylation, termed a minimal protein kinase-inducible domain. The encodable protein motif comprises a 7- or 8-residue sequence (DKDADXW or DKDADXXW), derived from EF-Hand calcium-binding domains, that is necessary but not sufficient for binding terbium, combined with a protein phosphorylation site (Ser or Thr at residue 9) that, upon phosphorylation, completes the metal-binding motif. Thus, the motif binds metal poorly and exhibits weak terbium luminescence when not phosphorylated. Upon phosphorylation, the peptide binds metal with significantly higher affinity and exhibits robust terbium luminescence. Phosphorylation results in up to a 23× increase in terbium luminescence. Minimal phosphorylation-dependent motifs as small as 9 residues (DKDADGWIS) were developed. NMR spectroscopy on this lanthanum(iii)·phosphopeptide complex confirmed that binding occurs in a manner similar to that in an EF-Hand, despite the absence of the conserved Glu12 typically present in an EF-Hand. By combining molecular design with known protein kinase recognition sequences, minimal protein kinase-inducible domains were developed that were responsive to phosphorylation by Protein Kinase A (PKA: DKDADRRW(S/pS)IIAK), Protein Kinase C (PKC: DKDADGWI(T/pT)FRRKA), and Casein Kinase 1 (CK1: DKDADDWA(S/pS)I). Phosphorylation by PKA was quantified in HeLa cell extracts, with a 4.4× increase in fluorescence (terbium luminescence) observed at 544 nm. The optimized minimal motif includes alternating aspartate residues at positions 1, 3, and 5, plus binding through the main-chain carbonyl at position 7; a lysine at position 2 to provide electrostatic balance and reduce binding in the absence of phosphorylation; an alanine at residue 4 to promote the αL conformation observed at that position of the EF Hand; a tryptophan at residue 7 or 8 to sensitize terbium luminescence; and a phosphorylation site with serine or threonine at residue 9. Residues at positions 6; 7 or 8; and 10 or later may be changed to provide kinase specificity. In the CK1-responsive peptide, the acidic residues in the proto-terbium-binding motif are employed as part of the kinase recognition sequence. This work thus presents fundamental rules for the design of compact phosphorylation-responsive terbium-binding motifs, with potential further application to motifs responsive to other protein post-translational modifications.
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Affiliation(s)
- Feng Gao
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA.
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On the use of X-ray absorption spectroscopy to elucidate the structure of lutetium adenosine mono- and triphosphate complexes. Anal Bioanal Chem 2013; 406:1049-61. [PMID: 23727732 DOI: 10.1007/s00216-013-7053-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Revised: 05/02/2013] [Accepted: 05/07/2013] [Indexed: 10/26/2022]
Abstract
Although the physiological impact of the actinide elements as nuclear toxicants has been widely investigated for half a century, a description of their interactions with biological molecules remains limited. It is however of primary importance to better assess the determinants of actinide speciation in cells and more generally in living organisms to unravel the molecular processes underlying actinide transport and deposition in tissues. The biological pathways of this family of elements in case of accidental contamination or chronic natural exposure (in the case of uranium rich soils for instance) are therefore a crucial issue of public health and of societal impact. Because of the high chemical affinity of those actinide elements for phosphate groups and the ubiquity of such chemical functions in biochemistry, phosphate derivatives are considered as probable targets of these cations. Among them, nucleotides and in particular adenosine mono- (AMP) and triphosphate (ATP) nucleotides occur in more chemical reactions than any other compounds on the earth's surface, except water, and are therefore critical target molecules. In the present study, we are interested in trans-plutonium actinide elements, in particular americium and curium that are more rarely considered in environmental and bioaccumulation studies than early actinides like uranium, neptunium and plutonium. A first step in this strategy is to work with chemical analogues like lanthanides that are not radioactive and therefore allow extended physical chemical characterization to be conducted that are difficult to perform with radioactive materials. We describe herein the interaction of lutetium(III) with adenosine AMP and ATP. With AMP and ATP, insoluble amorphous compounds have been obtained with molar ratios of 1:2 and 1:1, respectively. With an excess of ATP, with 1:2 molar ratio, a soluble complex has been obtained. A combination of spectroscopic techniques (IR, NMR, ESI-MS, EXAFS) together with quantum chemical calculations has been implemented in order to assess the lutetium coordination arrangement for the two nucleotides. In all the complexes described in the article, the lutetium cation is coordinated by the phosphate groups of the nucleotide plus additional putative water molecules with various tridimensional arrangements. With AMP 1:2 and ATP 1:1 solid-state compounds, polynuclear complexes are assumed to be obtained. In contrast, with ATP 1:2 soluble compound, the Lu coordination sphere is saturated by two ATP ligands, and this favors the formation of a mononuclear complex. In order to further interpret the EXAFS data obtained at the Lu LIII edge, model structures have been calculated for the 1:1 and 1:2 ATP complexes. They are discussed and compared to the EXAFS best fit metrical parameters.
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Chi CX, Xie H, Cong R, Tang ZC, Zhou MF. Electron Affinities of the Early Lanthanide Monoxide Molecules. CHINESE J CHEM PHYS 2011. [DOI: 10.1088/1674-0068/24/05/604-610] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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7
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Gaidamauskas E, Saejueng K, Holder AA, Bharuah S, Kashemirov BA, Crans DC, McKenna CE. Metal complexation chemistry used for phosphate and nucleotide determination: an investigation of the Yb3+-pyrocatechol violet sensor. J Biol Inorg Chem 2008; 13:1291-9. [PMID: 18704521 PMCID: PMC5117110 DOI: 10.1007/s00775-008-0415-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2008] [Accepted: 07/28/2008] [Indexed: 10/21/2022]
Abstract
Metal complexation reactions can be used effectively as sensors to measure concentrations of phosphate and phosphate analogs. Recently, a method was described for the detection of phosphate or ATP in aqueous solution based on the displacement by these ligands of pyrocatechol violet (PV) from a putative 2:1 (Yb3+)2PV complex. We have not been able to reproduce this stoichiometry and report this work in order to correct the coordination chemistry upon which sensor applications are based. In our work, colorimetric and spectrophotometric detection of phosphate was confirmed qualitatively (blue PV+Yb3+; yellow+Pi); however, the sequence of visual changes on the titration of PV with 2 equiv. of Yb3+ and back titration with ATP as described previously could not be reproduced. In contrast to the linear response to Pi that was reported previously, the absorbance response at 443 or 623 nm was found to be sigmoidal using the recommended 2:1 Yb3+:PV solution (100 microM:50 microM, pH 7, HEPES). Furthermore, both continuous variation titration and molar ratio analysis (Job plot) experiments are consistent with 1:1, not 2:1, YbPV complex stoichiometry at pH 7 in HEPES buffer, indicating that the deviation from linearity is produced by excess Yb3+. Indeed, using a 1:1 Yb3+:PV ratio produces a linear response in DeltaAbs at 443 or 623 nm on back titration with analyte (phosphate or ATP). In addition, speciation analysis of the Yb-ATP system demonstrates that a 1:1 complex containing Yb3+ and ATP predominates in solution at microM metal ion and ATP concentrations. Paramagnetic 1H NMR spectroscopy directly establishes the formation of Yb3+-solute complexes in dilute aqueous solution. The 1:1 YbPV complex can be used for the colorimetric measurement of phosphate and ATP concentrations from approximately 2 microM.
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Affiliation(s)
- Ernestas Gaidamauskas
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523-1872, USA
| | | | - Alvin A. Holder
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523-1872, USA
| | - Subalita Bharuah
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523-1872, USA
| | | | - Debbie C. Crans
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523-1872, USA
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9
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De Stefano C, Gianguzza A, Pettignano A, Sammartano S. Interaction of UO2(2+) with ATP in aqueous ionic media. Biophys Chem 2005; 117:147-53. [PMID: 15923076 DOI: 10.1016/j.bpc.2005.05.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2005] [Revised: 05/06/2005] [Accepted: 05/06/2005] [Indexed: 10/25/2022]
Abstract
Interaction of dioxouranium(VI) (uranyl) ion with ATP was studied by ligand/proton and metal/hydroxide displacement technique, at very low ionic strength and at I=0.15 mol L(-1), in aqueous Me4NCl and NaCl solutions, at t=25 degrees C. Measurements were carried out in the pH range 3-8.5, before the formation of precipitate. Computer analysis allowed us to find the quite stable species UO2(ATP)H2(0), UO2(ATP)H-, UO2(ATP)2-, UO2(ATP)2(6-), UO2(ATP)2H2(4-) and UO2(ATP)(OH)3- whose formation constants are (at I=0 mol L(-1)) logbeta(112)=18.21, logbeta(111)=14.70, logbeta(110)=9.14, logbeta(120)=12.84, logbeta(122)=24.82, and logbeta(11-1)=2.09, respectively. Different values were obtained in the above ionic media at I=0.15 mol L(-1) and the dependence on the ionic medium was interpreted in terms of interactions between the negatively charged complex species and cations of supporting electrolytes. The species more stable in NaCl than in Me4NCl are those with the highest negative charge, UO2(ATP)2(6-) and UO2(ATP)2H2(4-), and the extra stability of these species can be attributed to the interaction with Na+. Speciation profiles show that ATP can suppress UO2(2+) hydrolysis, and that in the neutral to slightly alkaline range the yield of complex UO2-ATP species is quite high. Comparison with other metal-ATP systems is also given in order to recognize the possibility of binding competition of uranyl ion in metal-ATP requiring enzymes for biochemical processes.
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Affiliation(s)
- Concetta De Stefano
- Dipartimento di Chimica Inorganica, Chimica Analitica e Chimica Fisica, Università di Messina, Salita Sperone 31, I-98166 Messina (S. Agata), Italy
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10
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Complexation of curium(III) by adenosine 5′-triphosphate (ATP): A time-resolved laser-induced fluorescence spectroscopy (TRLFS) study. Inorganica Chim Acta 2005. [DOI: 10.1016/j.ica.2004.12.055] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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11
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Klakamp SL, Horrocks WD. The europium (III)-induced conformational transitions of poly(dG-dC) · poly(dG-dC) and poly(dG-m5dC) · poly(dG-m5dC) as studied by europium(III) luminescence, UV, and CD spectroscopy. Biopolymers 2004. [DOI: 10.1002/bip.360300106] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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12
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Willson SP, Andrews L. Characterization of the Reaction Products of Laser-Ablated Early Lanthanide Metal Atoms with Molecular Oxygen. Infrared Spectra of LnO, LnO+, LnO-, LnO2, LnO2+, LnO2-, LnO3-, and (LnO)2 in Solid Argon. J Phys Chem A 1999. [DOI: 10.1021/jp990005m] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Stephen P. Willson
- Chemistry Department, University of Virginia, Charlottesville, Virginia 22901
| | - Lester Andrews
- Chemistry Department, University of Virginia, Charlottesville, Virginia 22901
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Vander Elst L, Muller RN. A 31P and 1H NMR relaxometric study of the interaction between adenosine triphosphate (ATP) and paramagnetic ions (Gd3+ and Mn2+). Inorganica Chim Acta 1998. [DOI: 10.1016/s0020-1693(97)05916-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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14
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Filler AG, Lever AM. Effects of cation substitutions on reverse transcriptase and on human immunodeficiency virus production. AIDS Res Hum Retroviruses 1997; 13:291-9. [PMID: 9071428 DOI: 10.1089/aid.1997.13.291] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Reverse transcription is a key aspect of the retroviral life cycle. The enzyme reverse transcriptase requires divalent cations, manganese or magnesium, for function. In some cation-dependent systems substitution of a physiological metal by a nonphysiological metal has been shown to work. We investigated the effect of different cations on HIV reverse transcriptase activity. The studies established reaction conditions for assaying different cations. A variety of transition metals were used in in vitro assays with HIV recombinant RT homodimer and some were delivered to HIV-infected cells in vitro to study effects on virus production. Most metals substituted adequately for magnesium. However, palladium showed a marked nonreversible inhibition of RT activity in vitro that correlated with reduced HIV virus production in tissue culture. A more extensive range of transition metals and divalent cations was tested for their effects on detection of HIV RT from infected cell supernatants. In these complex phenotypes were seen. In some cases the RT activity appeared to be more easily detectable. This may relate to calcium-dependent nucleases in cell supernatants being inhibited, leading to an apparent enhancement of RT activity, or may be due to direct effects on RT processivity.
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Affiliation(s)
- A G Filler
- Department of Cellular and Molecular Sciences, St. George's Hospital Medical School, London, UK
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Vander Elst L, Van Haverbeke Y, Goudemant JF, Muller RN. Stability assessment of gadolinium complexes by P-31 and H-1 relaxometry. Magn Reson Med 1994; 31:437-44. [PMID: 8208120 DOI: 10.1002/mrm.1910310413] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Longitudinal P-31 relaxation rate enhancements of phosphate groups have been measured at pH 7-7.2 and 310 degrees K on aqueous solutions containing adenosine triphosphate (ATP), phosphocreatine (PCr), inorganic phosphate (Pi) and some lanthanide complexes (Gd-DOTA, Gd-HPDO3A, Gd-DO3A, Gd-DTPA, Gd-DTPA-BMA). The macrocyclic complexes induce linear enhancements of the relaxation rates of all phosphorus nuclei. For Gd-DOTA and Gd-HPDO3A, the mechanism of the interaction with the P-31 nuclei seems to be of the outer sphere type and a better efficiency is noted for the "neutral" Gd-HPDO3A. A short-lived ternary complex between Gd-DO3A and the phosphorylated metabolites appears to be formed enabling an inner sphere interaction. In solutions containing the open chain complexes, Gd-DTPA and Gd-DTPA-BMA, P-31 relaxation rates of ATP exhibit significant and nonlinear enhancements that are much larger than those observed for PCr and Pi. A ternary complex involving the lanthanide ion, its original chelator, and the ATP molecule is precluded by various experiments which confirm that the lanthanide ion shifts from the original complexes to the ATP phosphate groups.
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Affiliation(s)
- L Vander Elst
- Department of Organic Chemistry, University of Mons-Hainaut, Belgium
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Affiliation(s)
- W D Horrocks
- Department of Chemistry, Pennsylvania State University, University Park 16802
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17
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Klakamp SL, Horrocks WD. Lanthanide ion luminescence as a probe of DNA structure. 1. Guanine-containing oligomers and nucleotides. J Inorg Biochem 1992; 46:175-92. [PMID: 1517730 DOI: 10.1016/0162-0134(92)80028-t] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Laser-induced Eu(3+) luminescence spectroscopy is used to probe the interaction of Eu(3+) ion with guanine-containing nucleotides and single-stranded oligomers. By using time-resolved and non-time-resolved Eu(3+) luminescence techniques, two classes of Eu(3+) binding site are observed in oligo(dG)10, oligo(dG)8, oligo(dG)6, oligo(dG)4, and d-GMP. One class of site binds Eu(3+) ions more strongly than the other. Since the "tight" class of bound Eu(3+) ions have two coordinated water molecules, it is inferred that six or seven atoms from the oligomers are coordinating the Eu(3+). The "weaker" class of Eu(3+) ion sites involve the coordination of six or seven water molecules and therefore, are coordinated by one or two atoms from the oligomer. The tight class of Eu(3+) binding site is attributed to an interstrand association of Eu(3+) with the oligomers forming dimeric or polymeric structures. The dissociation constants (Kd) for the 1:1 complexes Eu(d-GMP)+ and Eu(d-GTP)- have been determined as well as the Kd for the dimerization reaction of Eu(d-GMP)+. The Tb(3+) luminescence enhancement properties of these molecules are also examined in relation to their EU(3+) binding characteristics.
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Affiliation(s)
- S L Klakamp
- Department of Chemistry, Pennsylvania State University, University Park
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18
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McNemar CW, Horrocks WD. The determination of the Mg2+.ATP dissociation constant by competition with Eu3+ ion using laser-induced Eu3+ ion luminescence spectroscopy. Anal Biochem 1990; 184:35-8. [PMID: 2321757 DOI: 10.1016/0003-2697(90)90007-v] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A direct spectroscopic method for the determination of the submicromolar dissociation constant of Eu3+. ATP using laser-induced Eu3+ ion luminescence spectroscopy is described. The dissociation constant of Mg2+.ATP is then determined by the competition of Mg2+ with Eu3+ for the binding of ATP. The experiments were performed in 2H2O to mitigate the significant quenching of the Eu3+ luminescence that occurs in 1H2O. Values for the effective dissociation constants of the 1:1 ATP metal ion complexes of 1.2 +/- 0.3 X 10(-7) and 2.7 +/- 0.7 X 10(-4) M are obtained for Eu3+ and Mg2+, respectively, at p2H 5.8.
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Affiliation(s)
- C W McNemar
- Department of Chemistry, Pennsylvania State University, University Park 16802
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19
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Cader BM, Horrocks WD. A laser-induced europium (III) ion luminescence study of the interaction of this ion with phospholipid bilayer vesicles above and below the gel to liquid-crystalline phase transition temperature. Biophys Chem 1988; 32:97-109. [PMID: 3233318 DOI: 10.1016/0301-4622(88)85038-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Laser-induced europium(III) luminescence spectroscopy was used to investigate the formation and integrity of phospholipid bilayer vesicles produced by ultrasonication and detergent dialysis. Eu(III) ion interactions with these model biological membrane systems were explored. 7F0----5D0 spectral and excited-state lifetime data reveal two distinct, temperature-dependent binding sites, one involving a weak, 'superficial' interaction with the phosphate moiety of the phosphatidylcholine head group, the other involving a more tightly bound ion in a relatively dehydrated region of the head group. This latter 'sequestered' species appeared only at temperatures equal to or below that of the gel----liquid-crystalline phase transition. Systems containing various amounts of cholesterol showed a decrease in the formation of the sequestered species, indicative of a decrease in ion permeability. The results of this study demonstrate that the Eu(III) luminescence technique is useful for detecting major phase alterations in phospholipid bilayer vesicles.
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Affiliation(s)
- B M Cader
- Department of Chemistry, Pennsylvania State University, University Park 16802
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20
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Kirk WR, Amzel LM. Formycin triphosphate-terbium complex: a novel spectroscopic probe for phosphoryl transfer enzymes. BIOCHIMICA ET BIOPHYSICA ACTA 1987; 916:304-12. [PMID: 3689792 DOI: 10.1016/0167-4838(87)90174-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The conditions under which the fluorescent pyrazolopyrimidine nucleotide formycin A triphosphate (7-amino-3-(beta-D-(5'- tripolyphosphate)ribofuranosyl)pyrazolo[4,3-d]pyrimidine, FTP) forms a 1:1 complex in solution with Tb3+ have been characterized. The complex has a dissociation constant of approx. 10(-7) M. Within the complex, the luminescence of Tb3+ is dramatically sensitized by energy transfer from formycin. The value for 50% transfer efficiency, Förster's R0 (Förster, T. (1964) in Modern Quantum Chemistry (Sinanoglu, O., ed.), pp. 93-137, Academic Press, New York) was determined to be 3.34 +/- 0.4 A, and the effective distance between the donor and acceptor transition dipoles, R, in the complex was estimated to be 6.6 +/- 1.0 A. The quantum yield of Tb3+ in the complex is sensitive to the number of O-H oscillators bound to the Tb3+, which allows determination of the number of waters bound to it (approx. 4). Preliminary results show that the complex binds to the phosphoryl transfer enzyme hexokinase in the presence of the glucose analogs N-acetylglucosamine, frucose and xylose, which are not phosphorylated by the enzyme. The binding occurs with a loss of energy efficiency consistent with a new distance from the effective transition dipole of formycin to that of terbium of approx. 9.6 A. The FTP-terbium complex can be used as both a spectroscopic and an X-ray diffraction probe. Studies with this compound should be most valuable for correlating solution and crystallographic data.
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Affiliation(s)
- W R Kirk
- Laboratory of Molecular Structure and Function, Johns Hopkins University, School of Medicine, Baltimore, MD 21205
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Gangola P, Shamoo AE. Characterization of (Ca2+ + Mg2+)-ATPase of sarcoplasmic reticulum by laser-excited europium luminescence. EUROPEAN JOURNAL OF BIOCHEMISTRY 1987; 162:357-63. [PMID: 2948822 DOI: 10.1111/j.1432-1033.1987.tb10609.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The molecular environment of Ca2+ translocating sites of skeletal muscle sarcoplasmic reticulum (SR) (Ca2+ + Mg2+)-ATPase has been studied by pulsed-laser excited luminescence of Eu3+ used as a Ca2+ analogue. Interaction of Eu3+ with SR was characterized by investigating its effect on partial reactions of the Ca2+ transport cycle. In native SR vesicles, Eu3+ was found to inhibit Ca2+ binding, phosphoenzyme formation, ATP hydrolysis activity and Ca2+ uptake in parallel fashion. The non-specific binding of Eu3+ to acidic phospholipids associated with the enzyme was prevented by purifying (Ca2+ + Mg2+)-ATPase and exchanging the endogenous lipids with a neutral phospholipid, dioleoylglycerophosphocholine. The results demonstrate that the observed inhibition of Ca2+ transport by Eu3+ is due to its binding to Ca2+ translocating sites. The 7F0----5D0 transition of Eu3+ bound to these sites was monitored. The non-Lorentzian nature of the excitation profile and a double-exponential fluorescence decay revealed the heterogeneity of the two sites. Measurement of fluorescence decay rates in H2O/D2O mixture buffers further distinguished the sites. The number of water molecules in the first co-ordination sphere of Eu3+ bound at transport sites were found to be 4 and 1.5. Addition of ATP reduced these numbers to zero and 0.6. These data show that the calcium ions in translocating sites are well enclosed by protein ligands and are further occluded down to zero or one water molecule of solvation during the transport process.
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