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Del Giudice A, Rüter A, Pavel NV, Galantini L, Olsson U. Self-Assembly of Model Amphiphilic Peptides in Nonaqueous Solvents: Changing the Driving Force for Aggregation Does Not Change the Fibril Structure. Langmuir 2020; 36:8451-8460. [PMID: 32597180 PMCID: PMC8009514 DOI: 10.1021/acs.langmuir.0c00876] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Within the homologous series of amphiphilic peptides AnK, both A8K and A10K self-assemble in water to form twisted ribbon fibrils with lengths around 100 nm. The structure of the fibrils can be described in terms of twisted β-sheets extending in the direction of the fibrils, laminated to give a constant cross section of 4 nm by 8 nm. The finite width of the twisted ribbons can be reasonably explained within a simple thermodynamic model, considering a free energy penalty for the stretching of hydrogen bonds along the twisted β-sheets and an interfacial free energy gain for the lamination of the hydrophobic β-sheets. In this study, we characterize the self-assembly behavior of these peptides in nonaqueous solutions as a route to probe the role of hydrophobic interaction in fibril stabilization. Both peptides, in methanol and N,N-dimethylformamide, were found to form fibrillar aggregates with the same β-sheet structure as in water but with slightly smaller cross-sectional sizes. However, the gel-like texture, the slow relaxation in dynamic light scattering experiments, and a correlation peak in the small-angle X-ray scattering pattern highlighted enhanced interfibril interactions in the nonaqueous solvents in the same concentration range. This could be ascribed to a higher effective volume of the aggregates because of enhanced fibril growth and length, as suggested by light scattering and cryogenic transmission electron microscopy analyses. These effects can be discussed considering how the solvent properties affect the different energetic contributions (hydrophobic, electrostatic, and hydrogen bonding) to fibril formation. In the analyzed case, the decreased hydrogen bonding propensity of the nonaqueous solvents makes the hydrogen bond formation along the fibril a key driving force for peptide assembly, whereas it represents a nonrelevant contribution in water.
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Affiliation(s)
- Alessandra Del Giudice
- Department
of Chemistry, Sapienza University of Rome, P. le A. Moro 5, Rome 00185, Italy
| | - Axel Rüter
- Division
of Physical Chemistry, Lund University, Lund SE-22100, Sweden
| | - Nicolae Viorel Pavel
- Department
of Chemistry, Sapienza University of Rome, P. le A. Moro 5, Rome 00185, Italy
| | - Luciano Galantini
- Department
of Chemistry, Sapienza University of Rome, P. le A. Moro 5, Rome 00185, Italy
| | - Ulf Olsson
- Division
of Physical Chemistry, Lund University, Lund SE-22100, Sweden
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di Gregorio MC, Travaglini L, Del Giudice A, Cautela J, Pavel NV, Galantini L. Bile Salts: Natural Surfactants and Precursors of a Broad Family of Complex Amphiphiles. Langmuir 2019; 35:6803-6821. [PMID: 30234994 DOI: 10.1021/acs.langmuir.8b02657] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Bile salts (BSs) are naturally occurring rigid surfactants with a steroidal skeleton and specific self-assembly and interface behaviors. Using bile salts as precursors, derivatives can be synthesized to obtain molecules with specific functionalities and amphiphilic structure. Modifications on single molecules are normally performed by substituting the least-hindered hydroxyl group on carbon C-3 of the steroidal A ring or at the end of the lateral chain. This leads to monosteroidal rigid building blocks that are often able to self-organize into 1D structures such as tubules, twisted ribbons, and fibrils with helical supramolecular packing. Tubular aggregates are of particular interest, and they are characterized by cross-section inner diameters spanning a wide range of values (3-500 nm). They can form through appealing pH- or temperature-responsive aggregation and in mixtures of bile salt derivatives to provide mixed tubules with tunable charge and size. Other derivatives can be prepared by covalently linking two or more bile salt molecules to provide complex systems such as oligomers, dendrimers, and polymeric materials. The unconventional amphiphilic molecular structure imparts specific features to BSs and derivatives that can be exploited in the formulation of capsules, drug carriers, dispersants, and templates for the synthesis of nanomaterials.
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Affiliation(s)
| | - Leana Travaglini
- CNRS, ISIS UMR 7006 , Université de Strasbourg , 8 allée Gaspard Monge , 67000 Strasbourg , France
| | - Alessandra Del Giudice
- Dipartimento di Chimica , "Sapienza" Università di Roma , P. le A. Moro 5 , 00185 Roma , Italy
| | - Jacopo Cautela
- Dipartimento di Chimica , "Sapienza" Università di Roma , P. le A. Moro 5 , 00185 Roma , Italy
| | - Nicolae Viorel Pavel
- Dipartimento di Chimica , "Sapienza" Università di Roma , P. le A. Moro 5 , 00185 Roma , Italy
| | - Luciano Galantini
- Dipartimento di Chimica , "Sapienza" Università di Roma , P. le A. Moro 5 , 00185 Roma , Italy
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di Gregorio MC, Severoni E, Travaglini L, Gubitosi M, Sennato S, Mura F, Redondo-Gómez C, Jover A, Pavel NV, Galantini L. Bile acid derivative-based catanionic mixtures: versatile tools for superficial charge modulation of supramolecular lamellae and nanotubes. Phys Chem Chem Phys 2018; 20:18957-18968. [PMID: 29972162 DOI: 10.1039/c8cp02745e] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Self-assembled structures formed by mixtures of cationic and anionic surfactants are interesting tools for applications requiring interactions with charged particles and molecules. Nevertheless, they present instability close to the equimolar composition and poor morphological versatility, which is generally restricted to vesicles and micelles. Against this general trend, we report on bile salt derivative based catanionic mixtures assembling in tubules and lamellae depending on the mixture composition. Electrophoretic mobility measurements prove that the composition also dictates their superficial charge, which can be tuned from negative to positive by increasing the positively charged surfactant fraction in the mixtures. The study of the catanionic aggregates was conducted by means of microscopy and spectroscopy techniques and compared to the self-assembly behaviors of the individual building blocks. This study broadens the so far small array of bile salt derivative catanionic systems, confirming their distinctive behavior in the spectrum of catanionic mixtures.
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Tasca E, D'Abramo M, Galantini L, Giuliani AM, Pavel NV, Palazzo G, Giustini M. A Stereochemically Driven Supramolecular Polymerisation. Chemistry 2018; 24:8195-8204. [DOI: 10.1002/chem.201800644] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Indexed: 01/02/2023]
Affiliation(s)
- Elisamaria Tasca
- Chemistry Department; University “La Sapienza”; P.le Aldo Moro 5 00185 Rome Italy
| | - Marco D'Abramo
- Chemistry Department; University “La Sapienza”; P.le Aldo Moro 5 00185 Rome Italy
| | - Luciano Galantini
- Chemistry Department; University “La Sapienza”; P.le Aldo Moro 5 00185 Rome Italy
- Center for Colloid and Surface Science-C.S.G.I. Operative Unit of Bari c/o Chemistry Department; University “Aldo Moro”; Bari Italy
| | - Anna Maria Giuliani
- STEBICEF Department; University of Palermo; V.le delle Scienze 90128 Palermo Italy
| | - Nicolae Viorel Pavel
- Chemistry Department; University “La Sapienza”; P.le Aldo Moro 5 00185 Rome Italy
| | - Gerardo Palazzo
- Center for Colloid and Surface Science-C.S.G.I. Operative Unit of Bari c/o Chemistry Department; University “Aldo Moro”; Bari Italy
- Chemistry Department; University “Aldo Moro”; Via E. Orabona, 4 70126 Bari Italy
| | - Mauro Giustini
- Chemistry Department; University “La Sapienza”; P.le Aldo Moro 5 00185 Rome Italy
- Center for Colloid and Surface Science-C.S.G.I. Operative Unit of Bari c/o Chemistry Department; University “Aldo Moro”; Bari Italy
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di Gregorio MC, Gubitosi M, Travaglini L, Pavel NV, Jover A, Meijide F, Vázquez Tato J, Sennato S, Schillén K, Tranchini F, De Santis S, Masci G, Galantini L. Supramolecular assembly of a thermoresponsive steroidal surfactant with an oppositely charged thermoresponsive block copolymer. Phys Chem Chem Phys 2018; 19:1504-1515. [PMID: 27990552 DOI: 10.1039/c6cp05665b] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Supramolecular rearrangements are crucial in determining the response of stimuli sensitive soft matter systems such as those formed by mixtures of oppositely charged amphiphiles. Here mixtures of this kind were prepared by mixing the cationic block copolymer pAMPTMA30-b-pNIPAAM120 and an anionic surfactant obtained by the modification of the bile salt sodium cholate. As pure components, the two compounds presented a thermoresponsive self-assembly at around 30-35 °C; a micelle formation in the case of the copolymer and a transition from fibers to tubes in the case of the bile salt derivative. When both were present in the same solution they associated into mixed aggregates that showed complex thermoresponsive features. At room temperature, the core of the aggregate was comprised of a supramolecular twisted ribbon of the bile salt derivative. The block copolymers were anchored on the surface of this ribbon through electrostatic interactions between their charged blocks and the oppositely charged heads of the bile salt molecules. The whole structure was stabilized by a corona of the uncharged blocks that protruded into the surrounding solvent. By increasing the temperature to 30-34 °C the mixed aggregates transformed into rods with smooth edges that associated into bundles and clusters, which in turn induced clouding of the solution. Circular dichroism allowed us to follow progressive rearrangements of the supramolecular organization within the complex, occurring in the range of temperature of 20-70 °C.
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Affiliation(s)
- M C di Gregorio
- Department of Chemistry, "Sapienza" University of Rome, P.le A. Moro 5, 00185 Rome, Italy.
| | - M Gubitosi
- Department of Chemistry, "Sapienza" University of Rome, P.le A. Moro 5, 00185 Rome, Italy.
| | - L Travaglini
- Department of Chemistry, "Sapienza" University of Rome, P.le A. Moro 5, 00185 Rome, Italy.
| | - N V Pavel
- Department of Chemistry, "Sapienza" University of Rome, P.le A. Moro 5, 00185 Rome, Italy.
| | - A Jover
- Departamento de Química Física, Facultad de Ciencias, Universidad de Santiago de Compostela, Avda. Alfonso X El Sabio s/n, 27002 Lugo, Spain
| | - F Meijide
- Departamento de Química Física, Facultad de Ciencias, Universidad de Santiago de Compostela, Avda. Alfonso X El Sabio s/n, 27002 Lugo, Spain
| | - J Vázquez Tato
- Departamento de Química Física, Facultad de Ciencias, Universidad de Santiago de Compostela, Avda. Alfonso X El Sabio s/n, 27002 Lugo, Spain
| | - S Sennato
- Department of Physics and CNR-IPCF UOS Roma, "Sapienza" University of Rome, P.le A. Moro 5, 00185 Rome, Italy
| | - K Schillén
- Division of Physical Chemistry, Department of Chemistry, Lund University, SE-221 00 Lund, Sweden
| | - F Tranchini
- Department of Chemistry, "Sapienza" University of Rome, P.le A. Moro 5, 00185 Rome, Italy.
| | - S De Santis
- Department of Chemistry, "Sapienza" University of Rome, P.le A. Moro 5, 00185 Rome, Italy.
| | | | - L Galantini
- Department of Chemistry, "Sapienza" University of Rome, P.le A. Moro 5, 00185 Rome, Italy.
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Travaglini L, Giordano C, D'Annibale A, Gubitosi M, di Gregorio MC, Schillén K, Stefanucci A, Mollica A, Pavel NV, Galantini L. Twisted nanoribbons from a RGD-bearing cholic acid derivative. Colloids Surf B Biointerfaces 2017; 159:183-190. [PMID: 28787634 DOI: 10.1016/j.colsurfb.2017.07.084] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 07/05/2017] [Accepted: 07/29/2017] [Indexed: 11/16/2022]
Abstract
In light of the biomedical interest for self-assembling amphiphiles bearing the tripeptide Arg-Gly-Gly (RGD), a cholic acid derivative was synthesized by introducing an aromatic moiety on the steroidal skeleton and the RGD sequence on the carboxylic function of its chain 17-24, thus forming a peptide amphiphile with the unconventional rigid amphiphilic structure of bile salts. In aqueous solution, the compound self-assembled into long twisted ribbons characterized by a very low degree of polydispersity in terms of width (≈25nm), thickness (≈4.5nm) and pitch (≈145nm). It was proposed that in the ribbon the molecules are arranged in a bilayer structure with the aromatic moieties in the interior, strongly involved in the intermolecular interaction, whereas the RGD residues are located at the bilayer-water interface. The nanostructure is significantly different from those generally provided by RGD-containing amphiphiles with the conventional peptide-tail structure, for which fibers with a circular cross-section were observed, and successfully tested as scaffolds for tissue regeneration. From previous work on the use of this kind of nanostructures, it is known that features like morphology, rigidity, epitope spacing and periodicity are important factors that dramatically affect cell adhesion and signaling. Within this context, the reported results demonstrate that bile salt-based peptide surfactants are promising building blocks in the preparation of non-trivial RGD-decorated nanoaggregates with well-defined morphologies and epitope distributions.
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Affiliation(s)
- Leana Travaglini
- Department of Chemistry, Sapienza University of Rome, P.le A. Moro 5, 00185 Rome, Italy
| | - Cesare Giordano
- Institute of Molecular Biology and Pathology, CNR, P.le A. Moro 5, 00185 Roma, Italy
| | - Andrea D'Annibale
- Department of Chemistry, Sapienza University of Rome, P.le A. Moro 5, 00185 Rome, Italy
| | - Marta Gubitosi
- Department of Chemistry, Sapienza University of Rome, P.le A. Moro 5, 00185 Rome, Italy
| | | | - Karin Schillén
- Division of Physical Chemistry, Department of Chemistry, Center for Chemistry and Chemical Engineering, Lund University, SE-221 00 Lund, Sweden
| | - Azzurra Stefanucci
- Department of Pharmacy, University of Chieti-Pescara "G. d'Annunzio", Via dei Vestini 31, 66100 Chieti, Italy
| | - Adriano Mollica
- Department of Pharmacy, University of Chieti-Pescara "G. d'Annunzio", Via dei Vestini 31, 66100 Chieti, Italy
| | - Nicolae Viorel Pavel
- Department of Chemistry, Sapienza University of Rome, P.le A. Moro 5, 00185 Rome, Italy
| | - Luciano Galantini
- Department of Chemistry, Sapienza University of Rome, P.le A. Moro 5, 00185 Rome, Italy.
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7
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Del Giudice A, Pavel NV, Galantini L, Falini G, Trost P, Fermani S, Sparla F. Unravelling the shape and structural assembly of the photosynthetic GAPDH-CP12-PRK complex from Arabidopsis thaliana by small-angle X-ray scattering analysis. ACTA ACUST UNITED AC 2015; 71:2372-85. [PMID: 26627646 DOI: 10.1107/s1399004715018520] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 10/03/2015] [Indexed: 12/15/2022]
Abstract
Oxygenic photosynthetic organisms produce sugars through the Calvin-Benson cycle, a metabolism that is tightly linked to the light reactions of photosynthesis and is regulated by different mechanisms, including the formation of protein complexes. Two enzymes of the cycle, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and phosphoribulokinase (PRK), form a supramolecular complex with the regulatory protein CP12 with the formula (GAPDH-CP122-PRK)2, in which both enzyme activities are transiently inhibited during the night. Small-angle X-ray scattering analysis performed on both the GAPDH-CP12-PRK complex and its components, GAPDH-CP12 and PRK, from Arabidopsis thaliana showed that (i) PRK has an elongated, bent and screwed shape, (ii) the oxidized N-terminal region of CP12 that is not embedded in the GAPDH-CP12 complex prefers a compact conformation and (iii) the interaction of PRK with the N-terminal region of CP12 favours the approach of two GAPDH tetramers. The interaction between the GAPDH tetramers may contribute to the overall stabilization of the GAPDH-CP12-PRK complex, the structure of which is presented here for the first time.
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Affiliation(s)
| | | | | | - Giuseppe Falini
- Department of Chemistry `G. Ciamician', University of Bologna, Bologna, Italy
| | - Paolo Trost
- Department of Pharmacy and Biotechnology - FaBiT, University of Bologna, Bologna, Italy
| | - Simona Fermani
- Department of Chemistry `G. Ciamician', University of Bologna, Bologna, Italy
| | - Francesca Sparla
- Department of Pharmacy and Biotechnology - FaBiT, University of Bologna, Bologna, Italy
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Travaglini L, Gubitosi M, di Gregorio MC, Pavel NV, D'Annibale A, Giustini M, Soto Tellini VH, Vázquez Tato J, Obiols-Rabasa M, Bayati S, Galantini L. On the self-assembly of a tryptophan labeled deoxycholic acid. Phys Chem Chem Phys 2015; 16:19492-504. [PMID: 25103526 DOI: 10.1039/c4cp02371d] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Self-assembly of peptides and bile acids has been widely investigated because of their biological role and their potential as a tool for the preparation of nanostructured biomaterials. We herein report both the synthesis and the self-association behavior of a compound that combines the aggregation properties of bile acid- and amino acid-based molecules. The derivative has been prepared by introducing a L-tryptophan residue into the C-3 position of the deoxycholic acid skeleton and resulted in an amphoteric fluorescent labeled bile acid that shows a pH-dependent self-assembly. Under alkaline conditions it assembles into 28 nm diameter tubules, thus showing a completely different behavior compared to the precursor bile acid, which forms micelles under similar conditions. Upon heating the tubules break and turn into micelles, leading to an increase in the exposure to water of the tryptophan residue. On the other hand, in acidic solutions it aggregates into elongated micelles that further self-assemble forming a gel network, when an electrolyte is added.
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Affiliation(s)
- Leana Travaglini
- Department of Chemistry, "Sapienza" University of Rome, P. le A. Moro 5, 00185 Rome, Italy.
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Gubitosi M, Trillo JV, Alfaro Vargas A, Pavel NV, Gazzoli D, Sennato S, Jover A, Meijide F, Galantini L. Characterization of carbon nanotube dispersions in solutions of bile salts and derivatives containing aromatic substituents. J Phys Chem B 2014; 118:1012-21. [PMID: 24417378 DOI: 10.1021/jp407145t] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Bile salts (BS) are known to solubilize high weight fractions of carbon nanotubes (CNTs) in aqueous solutions. Here, the efficiency of derivatives of bile salts (BSDs) containing aromatic substituents in dispersing single-wall CNTs (SWCNTs) has been investigated in order to check whether the presence of aromatic residues, because of their affinity toward carbon nanotube surfaces, determines improvements of the BS dispersion efficiency (DE). Electric arc and CoMoCAT SWCNTs were analyzed. The results, reported for the two surfactant concentrations of 0.06 and 1.0 wt %, show that the DE of BSDs depends on the position, orientation, and structure of the introduced aromatic residues. In the case of the CoMoCAT SWCNTs, at low surfactant concentration a DE improvement is observed in BSDs where the aromatic residue is linked either to carbon 3, located on the rigid four-ring system, or to the side chain. For the latter, this improvement is also enhanced in double-charge derivatives and kept at high surfactant concentration. It was also observed that at low concentrations of surfactant, the DE values of BSs and BSDs are usually larger than those of the more conventional detergent sodium dodecylsulfate.
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Affiliation(s)
- Marta Gubitosi
- Dipartimento di Chimica, "Sapienza" Università di Roma , P. le A. Moro 5, 00185 Roma, Italy
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Benedetti M, Andreani F, Leggio C, Galantini L, Di Matteo A, Pavel NV, De Lorenzo G, Cervone F, Federici L, Sicilia F. A single amino-acid substitution allows endo-polygalacturonase of Fusarium verticillioides to acquire recognition by PGIP2 from Phaseolus vulgaris. PLoS One 2013; 8:e80610. [PMID: 24260434 DOI: 10.1371/10.1371/journal.pone.0080610] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Accepted: 10/12/2013] [Indexed: 05/25/2023] Open
Abstract
Polygalacturonases (PGs) are secreted by phytopathogenic fungi to degrade the plant cell wall homogalacturonan during plant infection. To counteract Pgs, plants have evolved polygalacturonase-inhibiting proteins (PGIPs) that slow down fungal infection and defend cell wall integrity. PGIPs favour the accumulation of oligogalacturonides, which are homogalacturonan fragments that act as endogenous elicitors of plant defence responses. We have previously shown that PGIP2 from Phaseolus vulgaris (PvPGIP2) forms a complex with PG from Fusarium phyllophilum (FpPG), hindering the enzyme active site cleft from substrate. Here we analyse by small angle X-ray scattering (SAXS) the interaction between PvPGIP2 and a PG from Colletotrichum lupini (CluPG1). We show a different shape of the PG-PGIP complex, which allows substrate entry and provides a structural explanation for the different inhibition kinetics exhibited by PvPGIP2 towards the two isoenzymes. The analysis of SAXS structures allowed us to investigate the basis of the inability of PG from Fusarium verticilloides (FvPG) to be inhibited by PvPGIP2 or by any other known PGIP. FvPG is 92.5% identical to FpPG, and we show here, by both loss- and gain-of-function mutations, that a single amino acid site acts as a switch for FvPG recognition by PvPGIP2.
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Affiliation(s)
- Manuel Benedetti
- Dipartimento di Biologia e Biotecnologie "Charles Darwin", Sapienza Università di Roma, Roma, Italy
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Benedetti M, Andreani F, Leggio C, Galantini L, Di Matteo A, Pavel NV, De Lorenzo G, Cervone F, Federici L, Sicilia F. A single amino-acid substitution allows endo-polygalacturonase of Fusarium verticillioides to acquire recognition by PGIP2 from Phaseolus vulgaris. PLoS One 2013; 8:e80610. [PMID: 24260434 PMCID: PMC3834070 DOI: 10.1371/journal.pone.0080610] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Accepted: 10/12/2013] [Indexed: 12/04/2022] Open
Abstract
Polygalacturonases (PGs) are secreted by phytopathogenic fungi to degrade the plant cell wall homogalacturonan during plant infection. To counteract Pgs, plants have evolved polygalacturonase-inhibiting proteins (PGIPs) that slow down fungal infection and defend cell wall integrity. PGIPs favour the accumulation of oligogalacturonides, which are homogalacturonan fragments that act as endogenous elicitors of plant defence responses. We have previously shown that PGIP2 from Phaseolus vulgaris (PvPGIP2) forms a complex with PG from Fusarium phyllophilum (FpPG), hindering the enzyme active site cleft from substrate. Here we analyse by small angle X-ray scattering (SAXS) the interaction between PvPGIP2 and a PG from Colletotrichum lupini (CluPG1). We show a different shape of the PG-PGIP complex, which allows substrate entry and provides a structural explanation for the different inhibition kinetics exhibited by PvPGIP2 towards the two isoenzymes. The analysis of SAXS structures allowed us to investigate the basis of the inability of PG from Fusarium verticilloides (FvPG) to be inhibited by PvPGIP2 or by any other known PGIP. FvPG is 92.5% identical to FpPG, and we show here, by both loss- and gain-of-function mutations, that a single amino acid site acts as a switch for FvPG recognition by PvPGIP2.
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Affiliation(s)
- Manuel Benedetti
- Dipartimento di Biologia e Biotecnologie “Charles Darwin”, Sapienza Università di Roma, Roma, Italy
| | - Federico Andreani
- Dipartimento di Biologia e Biotecnologie “Charles Darwin”, Sapienza Università di Roma, Roma, Italy
| | - Claudia Leggio
- Dipartimento di Chimica, Sapienza Università di Roma, Roma, Italy
| | | | - Adele Di Matteo
- Istituto di Biologia e Patologia Molecolari, Consiglio Nazionale delle Ricerche, Roma, Italy
| | | | - Giulia De Lorenzo
- Dipartimento di Biologia e Biotecnologie “Charles Darwin”, Sapienza Università di Roma, Roma, Italy
| | - Felice Cervone
- Dipartimento di Biologia e Biotecnologie “Charles Darwin”, Sapienza Università di Roma, Roma, Italy
| | - Luca Federici
- Dipartimento di Scienze Sperimentali e Cliniche and Centro Scienze dell’Invecchiamento, Università di Chieti-Pescara “G. d’ Annunzio”, Chieti, Italy
| | - Francesca Sicilia
- Dipartimento di Biologia e Biotecnologie “Charles Darwin”, Sapienza Università di Roma, Roma, Italy
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Margulis-Goshen K, di Gregorio MC, Pavel NV, Abezgauz L, Danino D, Vázquez Tato J, Soto Tellini VH, Magdassi S, Galantini L. Drug-loaded nanoparticles and supramolecular nanotubes formed from a volatile microemulsion with bile salt derivatives. Phys Chem Chem Phys 2013; 15:6016-24. [PMID: 23493872 DOI: 10.1039/c3cp50258a] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The main objective of this study was to form nanoparticles of a model hydrophobic drug, celecoxib, from a volatile microemulsion stabilized by a bile salt derivative. Nanoparticles were obtained by conversion of the microemulsion nanodroplets with the dissolved drug into solid nanometric particles. The use of bile salt derivatives as the surfactants for the formation of a microemulsion enabled significantly higher loading of the drug in both the microemulsion and nanoparticles, compared with the native bile salt. In addition, superior stability of the particles was achieved with the bile salt derivatives, and drug crystallization was inhibited. Interestingly, differences in particle stability and crystallization inhibition were observed between two bile salt derivatives differing only by one hydroxyl group on the bile salt backbone, indicating the delicate balance of interactions in the system. For one of the derivatives, upon dispersion of the nanoparticles in water, they spontaneously arranged into well-defined elongated nanometric tubules as detected and attested by cryo-TEM. It was found that the drug present in nanoparticles induces formation of the nanotubes.
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Affiliation(s)
- Katrin Margulis-Goshen
- The Hebrew University of Jerusalem, Edmond J. Safra campus, Givat Ram, Jerusalem, 91904, Israel
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Meijide F, Trillo JV, de Frutos S, Galantini L, Pavel NV, Soto VH, Jover A, Tato JV. Crystal structure of head-to-head dimers of cholic and deoxycholic acid derivatives with different symmetric bridges. Steroids 2013. [PMID: 23200733 DOI: 10.1016/j.steroids.2012.11.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The crystal structure of three head-to-head dimers (having two cholic acid or deoxycholic acid units) linked at carbon atoms C3 by aromatic or alkyl bridges is studied. An internal coordinates system is necessary for describing the relative orientation in the space of the two bile acid residues. Five angles (three torsion and two common ones) are necessary for defining the relative position of both steroid residues in space. Carbon atoms C3 (which always carries a α-hydroxy group in natural bile acids), and C10 and C13 (which always carry β-methyl groups) of each steroid residue are suitable for this purpose. Furthermore, the distance between each C3 carbon atoms of both steroid residues will allow one to locate the steroids in space. The three dimers selected provide a large range of values for these angles. The packing, hydrogen bond network, and location of guest in the three crystals are discussed.
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Affiliation(s)
- Francisco Meijide
- Departamento de Química Física, Facultad de Ciencias, Universidad de Santiago de Compostela, Avda. Alfonso X El Sabio s/n, 27002 Lugo, Spain
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14
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Meijide F, Trillo JV, de Frutos S, Galantini L, Pavel NV, Soto VH, Jover A, Vázquez Tato J. Formation of tubules by p-tert-butylphenylamide derivatives of chenodeoxycholic and ursodeoxycholic acids in aqueous solution. Steroids 2012; 77:1205-11. [PMID: 22917631 DOI: 10.1016/j.steroids.2012.07.017] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Revised: 07/13/2012] [Accepted: 07/26/2012] [Indexed: 11/28/2022]
Abstract
The formation of tubules by p-tert-butylphenylamide derivatives of chenodeoxycholic and ursodeoxycholic acids in aqueous solution is investigated. The critical aggregation concentrations of the new surfactants are much lower than those of ursodeoxycholate and chenodeoxycholate, indicating the enhanced surfactant properties resulting by the presence of the hydrophobic p-tert-butylphenyl group. The molecular areas at the air-water interface suggest the formation of monolayer films with molecules upright oriented. The shape of the aggregates was investigated by TEM. The main structure present in solution corresponds to tubules. The estimated value for the wall thickness of tubules suggests that a bilayer structure is formed. Host of positively charged latex beads by tubules suggests that their inner and outer surfaces are negatively charged. The acid form of the chenodeoxycholate derivative was recrystallized from toluene and its crystal structure analyzed.
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Affiliation(s)
- Francisco Meijide
- Departamento de Química Física, Facultad de Ciencias, Universidad de Santiago de Compostela, Avda. Alfonso X El Sabio s/n, Lugo 27002, Spain
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15
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Benedetti M, Leggio C, Federici L, De Lorenzo G, Pavel NV, Cervone F. Structural resolution of the complex between a fungal polygalacturonase and a plant polygalacturonase-inhibiting protein by small-angle X-ray scattering. Plant Physiol 2011; 157:599-607. [PMID: 21859985 PMCID: PMC3192570 DOI: 10.1104/pp.111.181057] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Accepted: 08/15/2011] [Indexed: 05/07/2023]
Abstract
We report here the low-resolution structure of the complex formed by the endo-polygalacturonase from Fusarium phyllophilum and one of the polygalacturonase-inhibiting protein from Phaseolus vulgaris after chemical cross-linking as determined by small-angle x-ray scattering analysis. The inhibitor engages its concave surface of the leucine-rich repeat domain with the enzyme. Both sides of the enzyme active site cleft interact with the inhibitor, accounting for the competitive mechanism of inhibition observed. The structure is in agreement with previous site-directed mutagenesis data and has been further validated with structure-guided mutations and subsequent assay of the inhibitory activity. The structure of the complex may help the design of inhibitors with improved or new recognition capabilities to be used for crop protection.
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Affiliation(s)
| | | | | | | | | | - Felice Cervone
- Dipartimento di Biologia e Biotecnologie C. Darwin (M.B., G.D.L., F.C.) and Dipartimento di Chimica (C.L., N.V.P.), Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza Università di Roma, 00185 Rome, Italy; Dipartimento di Scienze Biomediche, Centro Scienze dell’Invecchiamento, Universitá di Chieti G. D’Annunzio, 66013 Chieti, Italy (L.F.)
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Manghisi N, Leggio C, Jover A, Meijide F, Pavel NV, Soto Tellini VH, Vázquez Tato J, Agostino RG, Galantini L. Catanionic tubules with tunable charge. Angew Chem Int Ed Engl 2011; 49:6604-7. [PMID: 20718009 DOI: 10.1002/anie.201000951] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Nicola Manghisi
- Department of Chemistry, Sapienza University of Rome, P.le A. Moro 5, 00185 Rome, Italy
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Antelo A, Jover A, Galantini L, Meijide F, Alcalde MA, Pavel NV, Tato JV. Formation of host-guest and sandwich complexes by a β-cyclodextrin derivative. J INCL PHENOM MACRO 2010. [DOI: 10.1007/s10847-010-9835-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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18
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Meijide F, Antelo A, Alvarez Alcalde M, Jover A, Galantini L, Pavel NV, Vázquez Tato J. Supramolecular structures generated by a p-tert-butylphenylamide derivative of deoxycholic acid. From planar sheets to tubular structures through helical ribbons. Langmuir 2010; 26:7768-7773. [PMID: 20369848 DOI: 10.1021/la904548k] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The formation of supramolecular structures initiated by a p-tert-butylphenylamide derivative of deoxycholic acid (Na-t-butPhDC) is investigated. At 1.18 mM concentration of Na-t-butPhDC and 37 degrees C, initial flat ribbons are observed which self-transform into helical ribbons (with a mean pitch angle of 47 +/- 6 degrees) which finally originate molecular tubes with an external diameter of 241 +/- 28 nm. Most of the molecular tubes show helical markings with a pitch angle value of 45 +/- 4 degrees, in full agreement with predictions of simple models based on chiral elastic properties of the membrane. A lateral association mechanism is proposed to account for the growth of the external diameter (from 225 +/- 32 to 546 +/- 59 nm) of tubes with time at 3.99 mM.
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Affiliation(s)
- Francisco Meijide
- Departamento de Química Física, Facultad de Ciencias, Universidad de Santiago de Compostela, Avda. Alfonso X El Sabio s/n, 27002 Lugo, Spain
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19
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Alvarez Alcalde M, Jover A, Meijide F, Galantini L, Viorel Pavel N, Antelo A, Vázquez Tato J. Aggregation behavior of tetracarboxylic surfactants derived from cholic and deoxycholic acids and ethylenediaminetetraacetic acid. Langmuir 2009; 25:9037-9044. [PMID: 19719219 DOI: 10.1021/la9007813] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The reaction of 3beta-aminoderivatives of cholic and deoxycholic acids (steroid residues) with dimethyl ester of ethylenediaminetetraacetic acid (bridge) leads to the formation of dimers carrying four carboxylic organic functions, two of them located on the side chain of each steroid residue and the other two on the bridge. As tetrasodium salts, these new compounds behave as surfactants and have been characterized by surface tension, fluorescence intensity of pyrene (as a probe), and static and dynamic light scattering measurements. Thermodynamic parameters for micellization were obtained from the dependence of the critical micelle concentration (cmc) with temperature. For both surfactants, the fraction of bound counterions is close to 0.5. The aggregation behavior is similar to one of their bile salt residues [i.e., sodium cholate (NaC) and sodium deoxycholate (NaDC)] and can be summarized as follows: (i) molecular areas at the interface for the new surfactants are fairly close to twice the value for a single molecule in a monolayer of natural bile salts; (ii) the environment where pyrene is solubilized is very apolar, as in natural bile salt aggregates; (iii) Gibbs free energies (per steroid residue) for micellization are not far from published values for NaC and NaDC, and the differences can be understood on the basis of less hydrophobicity of the new surfactants due to the charges in the bridge; and (iv) as for NaC and NaDC, aggregates have rather low aggregation numbers (which depend on the amount of added inert salt, NaCl). A structure based on the disklike model accepted for small bile salt aggregates is proposed.
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Affiliation(s)
- Mercedes Alvarez Alcalde
- Departamento de Química Física, Facultad de Ciencias, Universidad de Santiago de Compostela, Avda. Alfonso X El Sabio s/n, 27002 Lugo, Spain
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de Petris G, Festa MR, Galantini L, Giglio E, Leggio C, Pavel NV, Troiani A. Sodium Glycodeoxycholate and Glycocholate Mixed Aggregates in Gas and Solution Phases. J Phys Chem B 2009; 113:7162-9. [DOI: 10.1021/jp9010586] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Giulia de Petris
- Dipartimento di Chimica, Research Center SOFT-INFM-CNR, and Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Università di Roma, P. le Aldo Moro 5, 00185 Roma, Italy
| | - Maria Rosa Festa
- Dipartimento di Chimica, Research Center SOFT-INFM-CNR, and Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Università di Roma, P. le Aldo Moro 5, 00185 Roma, Italy
| | - Luciano Galantini
- Dipartimento di Chimica, Research Center SOFT-INFM-CNR, and Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Università di Roma, P. le Aldo Moro 5, 00185 Roma, Italy
| | - Edoardo Giglio
- Dipartimento di Chimica, Research Center SOFT-INFM-CNR, and Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Università di Roma, P. le Aldo Moro 5, 00185 Roma, Italy
| | - Claudia Leggio
- Dipartimento di Chimica, Research Center SOFT-INFM-CNR, and Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Università di Roma, P. le Aldo Moro 5, 00185 Roma, Italy
| | - Nicolae Viorel Pavel
- Dipartimento di Chimica, Research Center SOFT-INFM-CNR, and Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Università di Roma, P. le Aldo Moro 5, 00185 Roma, Italy
| | - Anna Troiani
- Dipartimento di Chimica, Research Center SOFT-INFM-CNR, and Dipartimento di Chimica e Tecnologie del Farmaco, Sapienza Università di Roma, P. le Aldo Moro 5, 00185 Roma, Italy
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Galantini L, Leggio C, Pavel NV. Human Serum Albumin Unfolding: A Small-Angle X-ray Scattering and Light Scattering Study. J Phys Chem B 2008; 112:15460-9. [DOI: 10.1021/jp806821e] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Luciano Galantini
- Dipartimento di Chimica, Sapienza Università di Roma, P.O. Box 34−Roma 62, Pzz.le A. Moro 5, I-00185 Roma, Italy, and INFM CRS-SOFT, c/o Sapienza Università di Roma, Roma, Italy
| | - Claudia Leggio
- Dipartimento di Chimica, Sapienza Università di Roma, P.O. Box 34−Roma 62, Pzz.le A. Moro 5, I-00185 Roma, Italy, and INFM CRS-SOFT, c/o Sapienza Università di Roma, Roma, Italy
| | - Nicolae Viorel Pavel
- Dipartimento di Chimica, Sapienza Università di Roma, P.O. Box 34−Roma 62, Pzz.le A. Moro 5, I-00185 Roma, Italy, and INFM CRS-SOFT, c/o Sapienza Università di Roma, Roma, Italy
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22
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Galantini L, Jover A, Leggio C, Meijide F, Pavel NV, Tellini VHS, Tato JV, Tortolini C. Early Stages of Formation of Branched Host−Guest Supramolecular Polymers. J Phys Chem B 2008; 112:8536-41. [DOI: 10.1021/jp803496q] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Luciano Galantini
- Dipartimento di Chimica and Research center SOFT-INFM-CNR, Sapienza Università di Roma, P.le A. Moro 5, 00185 Roma, Italy, and Departamento de Química Física, Facultad de Ciencias, Universidad de Santiago de Compostela, Avda. Alfonso X El Sabio s/n, 27002 Lugo, Spain
| | - Aida Jover
- Dipartimento di Chimica and Research center SOFT-INFM-CNR, Sapienza Università di Roma, P.le A. Moro 5, 00185 Roma, Italy, and Departamento de Química Física, Facultad de Ciencias, Universidad de Santiago de Compostela, Avda. Alfonso X El Sabio s/n, 27002 Lugo, Spain
| | - Claudia Leggio
- Dipartimento di Chimica and Research center SOFT-INFM-CNR, Sapienza Università di Roma, P.le A. Moro 5, 00185 Roma, Italy, and Departamento de Química Física, Facultad de Ciencias, Universidad de Santiago de Compostela, Avda. Alfonso X El Sabio s/n, 27002 Lugo, Spain
| | - Francisco Meijide
- Dipartimento di Chimica and Research center SOFT-INFM-CNR, Sapienza Università di Roma, P.le A. Moro 5, 00185 Roma, Italy, and Departamento de Química Física, Facultad de Ciencias, Universidad de Santiago de Compostela, Avda. Alfonso X El Sabio s/n, 27002 Lugo, Spain
| | - Nicolae Viorel Pavel
- Dipartimento di Chimica and Research center SOFT-INFM-CNR, Sapienza Università di Roma, P.le A. Moro 5, 00185 Roma, Italy, and Departamento de Química Física, Facultad de Ciencias, Universidad de Santiago de Compostela, Avda. Alfonso X El Sabio s/n, 27002 Lugo, Spain
| | - Victor Hugo Soto Tellini
- Dipartimento di Chimica and Research center SOFT-INFM-CNR, Sapienza Università di Roma, P.le A. Moro 5, 00185 Roma, Italy, and Departamento de Química Física, Facultad de Ciencias, Universidad de Santiago de Compostela, Avda. Alfonso X El Sabio s/n, 27002 Lugo, Spain
| | - José Vázquez Tato
- Dipartimento di Chimica and Research center SOFT-INFM-CNR, Sapienza Università di Roma, P.le A. Moro 5, 00185 Roma, Italy, and Departamento de Química Física, Facultad de Ciencias, Universidad de Santiago de Compostela, Avda. Alfonso X El Sabio s/n, 27002 Lugo, Spain
| | - Cristina Tortolini
- Dipartimento di Chimica and Research center SOFT-INFM-CNR, Sapienza Università di Roma, P.le A. Moro 5, 00185 Roma, Italy, and Departamento de Química Física, Facultad de Ciencias, Universidad de Santiago de Compostela, Avda. Alfonso X El Sabio s/n, 27002 Lugo, Spain
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23
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Alvarez Alcalde M, Jover A, Meijide F, Galantini L, Pavel NV, Antelo A, Vázquez Tato J. Synthesis and characterization of a new gemini surfactant derived from 3alpha,12alpha-dihydroxy-5beta-cholan-24-amine (steroid residue) and ethylenediamintetraacetic acid (spacer). Langmuir 2008; 24:6060-6066. [PMID: 18498184 DOI: 10.1021/la7035218] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A new gemini steroid surfactant derived from 3alpha,12alpha-dihydroxy-5beta-cholan-24-amine (steroid residue) and ethylenediamintetraacetic acid (spacer) was synthesized and characterized in aqueous solution by surface tension, fluorescence intensity of pyrene, and light scattering (static and dynamic) measurements. These techniques evidence the existence of a threshold concentration (cac), below which a three layers film is formed at the air-water interface. Above the cac, two types of aggregates--micelles and vesicle-like aggregates--coexist in a metastable state. Filtration of a solution with a starting concentration of 2.6 mM (buffer 150 mM, pH 10) allows isolation of the micelles, which have an average aggregation number of 12, their density being 0.28 g cm(-3). Under conditions where only the vesicle-like aggregates are detected by dynamic light scattering, a value of 5.5 x 10(4) was obtained for their aggregation number at 30 microM, their density being 6.8 x 10(-4) g cm(-3). At high concentrations, the intensity ratio of the vibronic peaks of pyrene, I1/I3, (=0.68) is very close to published values for deoxycholate micelles, indicating that the probe is located in a region with a very low polarity and far from water. A hypothesis to explain the observed aggregation behavior (small aggregates are favored with increasing gemini concentration) is outlined.
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Affiliation(s)
- Mercedes Alvarez Alcalde
- Departamento de Química Física, Facultad de Ciencias, Universidad de Santiago de Compostela, Avenida Alfonso X El Sabio s/n, 27002 Lugo, Spain
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Leggio C, Galantini L, Pavel NV. About the albumin structure in solution: cigar Expanded form versus heart Normal shape. Phys Chem Chem Phys 2008; 10:6741-50. [DOI: 10.1039/b808938h] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Soto Tellini VH, Jover A, Galantini L, Pavel NV, Meijide F, Vázquez Tato J. New lamellar structure formed by an adamantyl derivative of cholic acid. J Phys Chem B 2007; 110:13679-81. [PMID: 16836308 DOI: 10.1021/jp062835n] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The self-aggregation of the sodium salt of a new adamantyl amide of the 3beta-amino derivative of cholic acid (Na-AdC) in aqueous solution has been investigated by surface tension, dynamic light scattering, fluorescence, small-angle X-ray scattering (SAXS), and transmission electron microscopy (TEM) measurements. These last two techniques suggest that a lamellar phase, consisting of charged bilayers of Na-AdC separated by solvent and periodically stacked, is formed in aqueous solution. The structure of the bilayer is inferred from the resolution of the crystal of the compound in its acid form. The adamantyl moieties, which are mutually interlocked, reside in the central region of the bilayer, and the carboxylic groups are directed toward the hydrophilic region. The structure is open enough to allow water molecules to interact with a fluorescence probe located at the central hydrophobic region.
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Leggio C, Anselmi M, Di Nola A, Galantini L, Jover A, Meijide F, Pavel NV, Tellini VHS, Tato JV. Study on the Structure of Host−Guest Supramolecular Polymers. Macromolecules 2007. [DOI: 10.1021/ma070704u] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Claudia Leggio
- Dipartimento di Chimica, Università di Roma “La Sapienza”, P.le A. Moro 5, 00185 Roma, Italy; Research Center SOFT-INFM-CNR, Università di Roma “La Sapienza”, P.le A. Moro 5, 00185 Roma, Italy; and Departamento de Química Física, Facultad de Ciencias, Universidad de Santiago de Compostela, Avda. Alfonso X El Sabio s/n, 27002 Lugo, Spain
| | - Massimiliano Anselmi
- Dipartimento di Chimica, Università di Roma “La Sapienza”, P.le A. Moro 5, 00185 Roma, Italy; Research Center SOFT-INFM-CNR, Università di Roma “La Sapienza”, P.le A. Moro 5, 00185 Roma, Italy; and Departamento de Química Física, Facultad de Ciencias, Universidad de Santiago de Compostela, Avda. Alfonso X El Sabio s/n, 27002 Lugo, Spain
| | - Alfredo Di Nola
- Dipartimento di Chimica, Università di Roma “La Sapienza”, P.le A. Moro 5, 00185 Roma, Italy; Research Center SOFT-INFM-CNR, Università di Roma “La Sapienza”, P.le A. Moro 5, 00185 Roma, Italy; and Departamento de Química Física, Facultad de Ciencias, Universidad de Santiago de Compostela, Avda. Alfonso X El Sabio s/n, 27002 Lugo, Spain
| | - Luciano Galantini
- Dipartimento di Chimica, Università di Roma “La Sapienza”, P.le A. Moro 5, 00185 Roma, Italy; Research Center SOFT-INFM-CNR, Università di Roma “La Sapienza”, P.le A. Moro 5, 00185 Roma, Italy; and Departamento de Química Física, Facultad de Ciencias, Universidad de Santiago de Compostela, Avda. Alfonso X El Sabio s/n, 27002 Lugo, Spain
| | - Aida Jover
- Dipartimento di Chimica, Università di Roma “La Sapienza”, P.le A. Moro 5, 00185 Roma, Italy; Research Center SOFT-INFM-CNR, Università di Roma “La Sapienza”, P.le A. Moro 5, 00185 Roma, Italy; and Departamento de Química Física, Facultad de Ciencias, Universidad de Santiago de Compostela, Avda. Alfonso X El Sabio s/n, 27002 Lugo, Spain
| | - Francisco Meijide
- Dipartimento di Chimica, Università di Roma “La Sapienza”, P.le A. Moro 5, 00185 Roma, Italy; Research Center SOFT-INFM-CNR, Università di Roma “La Sapienza”, P.le A. Moro 5, 00185 Roma, Italy; and Departamento de Química Física, Facultad de Ciencias, Universidad de Santiago de Compostela, Avda. Alfonso X El Sabio s/n, 27002 Lugo, Spain
| | - Nicolae Viorel Pavel
- Dipartimento di Chimica, Università di Roma “La Sapienza”, P.le A. Moro 5, 00185 Roma, Italy; Research Center SOFT-INFM-CNR, Università di Roma “La Sapienza”, P.le A. Moro 5, 00185 Roma, Italy; and Departamento de Química Física, Facultad de Ciencias, Universidad de Santiago de Compostela, Avda. Alfonso X El Sabio s/n, 27002 Lugo, Spain
| | - Victor Hugo Soto Tellini
- Dipartimento di Chimica, Università di Roma “La Sapienza”, P.le A. Moro 5, 00185 Roma, Italy; Research Center SOFT-INFM-CNR, Università di Roma “La Sapienza”, P.le A. Moro 5, 00185 Roma, Italy; and Departamento de Química Física, Facultad de Ciencias, Universidad de Santiago de Compostela, Avda. Alfonso X El Sabio s/n, 27002 Lugo, Spain
| | - José Vázquez Tato
- Dipartimento di Chimica, Università di Roma “La Sapienza”, P.le A. Moro 5, 00185 Roma, Italy; Research Center SOFT-INFM-CNR, Università di Roma “La Sapienza”, P.le A. Moro 5, 00185 Roma, Italy; and Departamento de Química Física, Facultad de Ciencias, Universidad de Santiago de Compostela, Avda. Alfonso X El Sabio s/n, 27002 Lugo, Spain
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Galantini L, Giglio E, Pavel NV. Comment on "Two-dimensional NMR study on the structures of micelles of sodium taurocholate". J Phys Chem B 2007; 109:9849-50. [PMID: 16852186 DOI: 10.1021/jp0477708] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- L Galantini
- Dipartimento di Chimica, Università di Roma La Sapienza, P. le A. Moro 5, 00185 Roma, Italy
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Cozzolino S, Galantini L, Giglio E, Hoffmann S, Leggio C, Pavel NV. Structure of Sodium Glycodeoxycholate Micellar Aggregates from Small-Angle X-ray Scattering and Light-Scattering Techniques. J Phys Chem B 2006; 110:12351-9. [PMID: 16800558 DOI: 10.1021/jp060712x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Small-angle X-ray scattering (SAXS) and dynamic light scattering (DLS) measurements were accomplished on sodium glycodeoxycholate (NaGDC) aqueous electrolyte solutions as a function of NaGDC and NaCl concentrations with the aim to determine with satisfactory approximation the NaGDC micellar aggregate structure at a gross molecular level, assuming monodispersity. Different conditions of interparticle interactions by varying ionic strength (NaCl concentration from 0 to 0.70 M) and NaGDC concentration (from 0.02 to 0.10 M) were studied. Smeared scattering intensities and electron pair distance distribution functions, radii of gyration, and aggregate heights are in satisfactory agreement with the corresponding functions calculated using a 2(1) helix as model. It is formed by trimers, each one composed by three NaGDC and nine H2O molecules related by a 3-fold rotation axis, and can be described by a hollow cylinder, probably filled by water molecules, characterized by a conventional radius of 23.7 A and a trimer repeat along the helical axis of 3.6 A. The helix is considerably inhomogeneous since the volume of the cylinder occupied by NaGDC molecules is less than one-third of the total. On the other hand, calculations performed with the average radial electronic density of the helix without water molecules or totally filled by water molecules (a NaGDC/H2O molecular ratio of about 1/50) or by using a three-shell average radial electronic density, independently evaluated on absolute scale, do not show significant differences, thus supporting the helical model. The aggregate size increases for all the samples by increasing either the NaCl or NaGDC concentration. The NaGDC low concentration (0.02 M) samples with NaCl within the range 0.30-0.70 M are characterized by short cylindrical aggregates that do not give rise to sensible interference effects. This assertion is supported by the satisfactory fit between the observed apparent mean hydrodynamic radii and the calculated ones by means of the method of Ortega and Garcia de la Torre (J. Chem. Phys. 2003, 119, 9914), valid for rods with a length-to-diameter ratio > or = 0.1 in dilute solution (noninteracting rods). The NaGDC moderate concentration (0.10 M) samples with NaCl within the range 0.20-0.60 M are characterized by cylindrical aggregates that, in the presence of repulsive Coulombic interactions progressively more and more screened, produce interference effects, due to the hard-body repulsion and attractive forces, but the agreement between observed and calculated SAXS data is satisfactory. The results of the low and moderate NaGDC concentration samples seem to indicate that the aggregation number increase, produced by adding 0.10 M NaCl, is constant within an ionic strength range and occurs by the addition of oligomers formed by trimers. The samples with a variable NaGDC concentration (0.02-0.10 M) at a fixed and high NaCl concentration (0.6 M) contain cylindrical aggregates that give rise to an attractive term effect prevailing on the hard-body repulsive one. The same situation seems to occur in the NaGDC moderate concentration samples.
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Affiliation(s)
- Sara Cozzolino
- Dipartimento di Chimica and Research Center SOFT-INFM-CNR, Università di Roma La Sapienza, P.le A. Moro 5, 00185 Roma, Italy
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Leggio C, Galantini L, Zaccarelli E, Pavel NV. Small-Angle X-ray Scattering and Light Scattering on Lysozyme and Sodium Glycocholate Micelles. J Phys Chem B 2005; 109:23857-69. [PMID: 16375371 DOI: 10.1021/jp053603b] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Small-angle X-ray scattering (SAXS) together with static (SLS) and dynamic light scattering (DLS) measurements were carried out on aqueous solutions of lysozyme (LY) and of the ionic biological detergent sodium glycocholate (NaGC). Apparent diffusion coefficients (D app), excess Rayleigh ratio, and SAXS spectra were measured for 0.1 M NaGC solutions at different ionic strengths (0.05-0.30 M NaCl). The same data were collected for LY in sodium acetate buffer 50 mM without and with 92 mM NaCl as a function of protein concentration (10-80 g L(-1)). A correlated analysis of SLS data and SAXS spectra was first tested on the LY samples and then extended to the interpretation of the NaGC data to infer information on particle structure and interaction potential. A hard-core (HC) interaction shell of uniform thickness, a screened Coulomb potential of the electric double layer (EDL) or the complete DLVO potential were alternatively used to represent the long-range tail of the interaction potential. Whenever an essentially repulsive tail is expected, all the representations give reasonable results, but the data analysis does not allow the discrimination between the oblate and the prolate symmetries of the NaGC aggregates. The DLVO model allows the interpretation of the data even when the attractive component determines the tail character. With this model an overall fit of the micelle data at all the NaCl concentrations was successfully performed by assuming a simple spherical symmetry of the micelles and invariant values of their ionization degree and Hamaker constant, thus considering just the screening effect of the added electrolyte. Whatever model is used, the results point out that the aggregates are quite hydrated (26-38 water molecules per monomer) and very slightly grow by increasing the NaCl concentration. When spherical symmetry is assumed the aggregate radii for all the samples fall in the range 15-16 A. From the SAXS and SLS, best fitting geometrical parameters, and interparticle structure factor, a D app value was calculated for each sample. An excellent consistence is achieved for LY results. On the contrary, calculated D app values systematically lower than the experimental values are always obtained for the NaGC micelles. Micelle polydispersity and internal dynamics seem to be the most probable reasons of the bad agreement.
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Affiliation(s)
- Claudia Leggio
- Dipartimento di Chimica, Research Center SOFT-INFM-CNR, and Dipartimento di Fisica, Università di Roma "La Sapienza", P.le A. Moro 5, 00185 Roma, Italy
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Cozzolino S, Galantini L, Leggio C, Pavel NV. Correlation between Small-Angle X-ray Scattering Spectra and Apparent Diffusion Coefficients in the Study of Structure and Interaction of Sodium Taurodeoxycholate Micelles. J Phys Chem B 2005; 109:6111-20. [PMID: 16851673 DOI: 10.1021/jp044540k] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Small-Angle X-ray Scattering (SAXS) and Dynamic Light Scattering (DLS) measurements were carried out on aqueous micellar solutions of the ionic biological detergent sodium taurodeoxycholate (NaTDC). Apparent diffusion coefficients (D(app)) and SAXS spectra of NaTDC 0.1 M solutions at different ionic strengths (0.1-0.3 M NaCl) were reported. A comparative analysis of SAXS spectra and D(app) data was performed to infer information on particle structure and interaction potential. Uniform particles with a spherical, an oblate, and a prolate symmetry were used to model the micelles in the data interpretation. A hard-core interaction shell of suitable thickness and a screened Coulomb potential of the electric double layer (EDL potential) were alternatively used to represent the long-range repulsive tail of the interaction potential. The Percus Yevick and the Rescaled Mean Spherical Approximation were applied. To compare the data of the two techniques, for each sample, a D(app) was calculated from the SAXS best-fitting geometrical parameters and interparticle structure factor of the micelles. Hence, a fitting procedure involving both the scattering and D(app) data was performed. The interpretation of SAXS spectra does not allow the discrimination between the oblate and the prolate symmetries of the aggregates. On the other hand, the comparison of calculated and experimental D(app) values indicates that the prolate ellipsoid is better suited to represent the micelle shape. Moreover, the agreement between calculated and experimental D(app) values is sensitively better at the lowest NaCl concentration when the EDL potential is used. A rodlike micellar growth and a progressive screening of the electrostatic interactions is testified by the trends of best-fitting parameters as a function of the added electrolyte.
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Affiliation(s)
- Sara Cozzolino
- Dipartimento di Chimica, Università di Roma La Sapienza, P. le A. Moro 5, 00185 Roma, Italy
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Affiliation(s)
- Paola D'Angelo
- Dipartimento di Chimica, Università di Roma “La Sapienza”, P.O. Box 34 - Roma 62, Pzz.le A. Moro 5, I-00185 Roma, Italy, INFM UdF Camerino, Italy, and ESRF, BP 220, F-38043 Grenoble Cedex, France
| | - Pierre-Emmanuel Petit
- Dipartimento di Chimica, Università di Roma “La Sapienza”, P.O. Box 34 - Roma 62, Pzz.le A. Moro 5, I-00185 Roma, Italy, INFM UdF Camerino, Italy, and ESRF, BP 220, F-38043 Grenoble Cedex, France
| | - Nicolae Viorel Pavel
- Dipartimento di Chimica, Università di Roma “La Sapienza”, P.O. Box 34 - Roma 62, Pzz.le A. Moro 5, I-00185 Roma, Italy, INFM UdF Camerino, Italy, and ESRF, BP 220, F-38043 Grenoble Cedex, France
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Galantini L, Giampaolo SM, Mannina L, Pavel NV, Viel S. Study of Intermicellar Interactions and Micellar Sizes in Ionic Micelle Solutions by Comparing Collective Diffusion and Self-Diffusion Coefficients. J Phys Chem B 2004. [DOI: 10.1021/jp037328+] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Galantini L, Giglio E, Leonelli A, Pavel NV. An Integrated Study of Small-Angle X-ray Scattering and Dynamic Light Scattering on Cylindrical Micelles of Sodium Glycodeoxycholate. J Phys Chem B 2004. [DOI: 10.1021/jp036746b] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Luciano Galantini
- Dipartimento di Chimica, Università di Roma “La Sapienza”, P.le A. Moro 5, 00185 Roma, Italy
| | - Edoardo Giglio
- Dipartimento di Chimica, Università di Roma “La Sapienza”, P.le A. Moro 5, 00185 Roma, Italy
| | - Antonio Leonelli
- Dipartimento di Chimica, Università di Roma “La Sapienza”, P.le A. Moro 5, 00185 Roma, Italy
| | - Nicolae Viorel Pavel
- Dipartimento di Chimica, Università di Roma “La Sapienza”, P.le A. Moro 5, 00185 Roma, Italy
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Galantini L, Pavel NV. Collective diffusion and self-diffusion coefficients comparison to separate interactions and micellar size effects on ionic micelle diffusivities: Cylindrical micelles of sodium taurodeoxycholate. J Chem Phys 2003. [DOI: 10.1063/1.1536050] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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D'Angelo P, Barone V, Chillemi G, Sanna N, Meyer-Klaucke W, Pavel NV. Hydrogen and higher shell contributions in Zn2+, Ni2+, and Co2+ aqueous solutions: an X-ray absorption fine structure and molecular dynamics study. J Am Chem Soc 2002; 124:1958-67. [PMID: 11866609 DOI: 10.1021/ja015685x] [Citation(s) in RCA: 155] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A detailed investigation of the hydration structure of Zn2+, Ni2+, and Co2+ in water solutions has been carried out combining X-ray absorption fine structure (EXAFS) spectroscopy and Molecular Dynamics (MD) simulations. The first quantitative analysis of EXAFS from hydrogen atoms in 3d transition metal ions in aqueous solutions has been carried out and the ion-hydrogen interactions have been found to provide a detectable contribution to the EXAFS spectra. An accurate determination of the structural parameters associated with the first hydration shell has been performed and compared with previous experimental results. No evidence of significant contributions from the second hydration shell to the EXAFS signal has been found for these solutions, while the inclusion of the hydrogen signal has been found to be important in performing a quantitative analysis of the experimental data. The high-frequency contribution present in the EXAFS spectra has been found to be due to multiple scattering (MS) effects inside the ion-oxygen first coordination shell. MD has been used to generate three-body distribution functions from which a reliable analysis of the MS contributions to the EXAFS spectra of these systems has been carried out.
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Affiliation(s)
- Paola D'Angelo
- Dipartimento di Chimica, Università di Roma La Sapienza, P. le A. Moro 5, 00185 Roma, Italy
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Chillemi G, D'Angelo P, Pavel NV, Sanna N, Barone V. Development and validation of an integrated computational approach for the study of ionic species in solution by means of effective two-body potentials. The case of Zn2+, Ni2+, and Co2+ in aqueous solutions. J Am Chem Soc 2002; 124:1968-76. [PMID: 11866610 DOI: 10.1021/ja015686p] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this paper we have developed an effective computational procedure for the structural and dynamical investigation of ions in aqueous solutions. Quantum mechanical potential energy surfaces for the interaction of a transition metal ion with a water molecule have been calculated taking into account the effect of bulk solvent by the polarizable continuum model (PCM). The effective ion-water interactions have been fitted by suitable analytical potentials, and have been utilized in molecular dynamics (MD) simulations to obtain structural and dynamical properties of the ionic aqueous solutions. This procedure has been successfully applied to the Co2+-H2O open-shell system and, for the first time, Co-oxygen and Co-hydrogen pair potential functions have been determined and employed in MD simulations. The reliability of the whole procedure has been assessed by applying it also to the Zn2+ and Ni2+ aqueous solutions, and the structural and dynamical properties of the three systems have been calculated by means of MD simulations and have been found to be in very good agreement with experimental results. The structural parameters of the first solvation shells issuing from the MD simulations provide an effective complement to extended X-ray absorption fine structure (EXAFS) experiments.
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Affiliation(s)
- Giovanni Chillemi
- CASPUR, c/o Università di Roma La Sapienza, P.le Aldo Moro 5, 00185 ROMA, Italy
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D'Angelo P, Pavel NV. EXAFS and molecular dynamics studies of ionic solutions. J Synchrotron Radiat 2001; 8:173-177. [PMID: 11512719 DOI: 10.1107/s0909049500016319] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2000] [Accepted: 11/07/2000] [Indexed: 05/23/2023]
Abstract
This paper focuses on recent advances in the X-ray absorption spectroscopy (XAS) analysis of ionic solutions. The asymmetry of radial distribution functions g(r) associated with the solvent molecules surrounding the ions has to be taken into account to perform a reliable structural analysis. Molecular dynamics (MD) simulations provide reliable g(r)'s which can be used as starting models in the XAS data analysis. The combined MD-XAS investigation reduces meaningfully the indetermination of the structural parameters, especially for coordination numbers and Debye-Waller factors. Double-electron excitation channels can be present in the XAS spectra of ionic solutions and they have to be accounted for in the background extraction. The ability of the XAS technique to probe three-body correlation functions in ionic solutions with the aid of MD g(r1, r2, theta) has been shown. The analysis of the low-k region of the spectra allows the detection of a weak but significant hydrogen structural signal. The XAS technique is especially well suited to determine the detailed shape of the nearest-neighbor peak in the atom-atom pair correlation functions of disordered systems. The information that they contain about the short-range atom-atom pairwise interactions can be very helpful for specifying and properly modifying model potentials used in MD simulations.
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Affiliation(s)
- P D'Angelo
- Dipartimento di Chimica, Università degli Studi di Roma La Sapienza, Italy.
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D'Angelo P, Pavel NV, Borowski M. K- and L-edge XAFS determination of the local structure of aqueous Nd(III) and Eu(III). J Synchrotron Radiat 2001; 8:666-668. [PMID: 11512889 DOI: 10.1107/s0909049500016745] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2000] [Accepted: 11/10/2000] [Indexed: 05/23/2023]
Abstract
The short-range coordination of Nd(III) and Eu(III) ions in aqueous solutions has been investigated by means of K-edge x-ray absorption spectroscopy. Experimental data are presented which demonstrate that an accurate determination of the Nd(III) and Eu(III) hydration structural parameters can be obtained from the analysis of the K-edge spectra. It is shown that the large widths of the core hole states do not appreciably reduce the potential structural information of the K-edge EXAFS data. In addition the available k-range of the K-edge spectra is much wider compared to that of the L3-edge which is affected by the presence of double-electron excitations in a more severe fashion.
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Affiliation(s)
- P D'Angelo
- Dipartimento di Chimica, Università degli Studi di Roma La Sapienza, Italy.
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D'Angelo P, Pavel NV. Determination of two- and three-body correlation functions in ionic solutions by means of MD and EXAFS investigations. J Synchrotron Radiat 1999; 6:281-283. [PMID: 15263279 DOI: 10.1107/s0909049599000801] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/1998] [Accepted: 01/14/1999] [Indexed: 05/24/2023]
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D'Angelo P, Pavel NV, Roccatano D, Nolting H. Multielectron excitations at the L edges of barium in aqueous solution. Phys Rev B Condens Matter 1996; 54:12129-12138. [PMID: 9985072 DOI: 10.1103/physrevb.54.12129] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Bianconi A, Pavel NV, Benfatto M, Marcelli A, Natoli CR, Pianetta P, Woicik J. Multiple-scattering effects in the K-edge x-ray-absorption near-edge structure of crystalline and amorphous silicon. Phys Rev B Condens Matter 1987; 36:6426-6433. [PMID: 9942352 DOI: 10.1103/physrevb.36.6426] [Citation(s) in RCA: 71] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Coiro VM, Giglio E, Mazza F, Pavel NV. Crystal structure of the 2:1 inclusion compound between deoxycholic acid and quadricyclane. ACTA ACUST UNITED AC 1984. [DOI: 10.1007/bf00665476] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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