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Cordeiro MM, Filipe HAL, dos Santos P, Samelo J, Ramalho JPP, Loura LMS, Moreno MJ. Interaction of Hoechst 33342 with POPC Membranes at Different pH Values. Molecules 2023; 28:5640. [PMID: 37570608 PMCID: PMC10420284 DOI: 10.3390/molecules28155640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 07/18/2023] [Accepted: 07/21/2023] [Indexed: 08/13/2023] Open
Abstract
Hoechst 33342 (H33342) is a fluorescent probe that is commonly used to stain the DNA of living cells. To do so, it needs to interact with and permeate through cell membranes, despite its high overall charge at physiological pH values. In this work, we address the effect of pH in the association of H33342 with lipid bilayers using a combined experimental and computational approach. The partition of H33342 to 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) lipid membranes was experimentally quantified using fluorescence spectroscopy and isothermal titration calorimetry (ITC) measurements. Quantum chemical calculations were performed to select the most stable isomer of H33342 for the overall charges 0, +1, and +2, expected to predominate across the 5 < pH < 10 range. The interaction of these isomers with POPC bilayers was then studied by both unrestrained and umbrella sampling molecular dynamics (MD) simulations. Both experimental results and computational free energy profiles indicate that the partition coefficient of H33342 displays a small variation over a wide pH range, not exceeding one order of magnitude. The enthalpy variation upon partition to the membrane suggests efficient hydrogen bonding between the probe and the lipid, namely, for the protonated +2 form, which was confirmed in the MD simulation studies. The relatively high lipophilicity obtained for the charged species contrasts with the decrease in their general hydrophobicity as estimated from octanol/water partition. This highlights the distinction between lipophilicity and hydrophobicity, as well as the importance of considering the association with lipid bilayers when predicting the affinity for biomembranes.
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Affiliation(s)
- Margarida M. Cordeiro
- Coimbra Chemistry Center, Institute of Molecular Sciences (CQC-IMS), University of Coimbra, 3004-535 Coimbra, Portugal; (M.M.C.); (H.A.L.F.); (J.S.)
- Department of Chemistry, Faculty of Sciences and Technology, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Hugo A. L. Filipe
- Coimbra Chemistry Center, Institute of Molecular Sciences (CQC-IMS), University of Coimbra, 3004-535 Coimbra, Portugal; (M.M.C.); (H.A.L.F.); (J.S.)
- Polytechnic of Guarda, CPIRN-IPG—Center of Potential and Innovation of Natural Resources, 6300-559 Guarda, Portugal
| | - Patrícia dos Santos
- Coimbra Chemistry Center, Institute of Molecular Sciences (CQC-IMS), University of Coimbra, 3004-535 Coimbra, Portugal; (M.M.C.); (H.A.L.F.); (J.S.)
- Department of Chemistry, Faculty of Sciences and Technology, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Jaime Samelo
- Coimbra Chemistry Center, Institute of Molecular Sciences (CQC-IMS), University of Coimbra, 3004-535 Coimbra, Portugal; (M.M.C.); (H.A.L.F.); (J.S.)
- Department of Chemistry, Faculty of Sciences and Technology, University of Coimbra, 3004-535 Coimbra, Portugal
| | - João P. Prates Ramalho
- LAQV, REQUIMTE, Hercules Laboratory, Department of Chemistry, School of Science and Technology, University of Évora, 7000-671 Évora, Portugal;
| | - Luís M. S. Loura
- Coimbra Chemistry Center, Institute of Molecular Sciences (CQC-IMS), University of Coimbra, 3004-535 Coimbra, Portugal; (M.M.C.); (H.A.L.F.); (J.S.)
- CNC—Center for Neuroscience and Cell Biology, University of Coimbra, 3004-535 Coimbra, Portugal
- Faculty of Pharmacy, University of Coimbra, 3000-548 Coimbra, Portugal
| | - Maria J. Moreno
- Coimbra Chemistry Center, Institute of Molecular Sciences (CQC-IMS), University of Coimbra, 3004-535 Coimbra, Portugal; (M.M.C.); (H.A.L.F.); (J.S.)
- Department of Chemistry, Faculty of Sciences and Technology, University of Coimbra, 3004-535 Coimbra, Portugal
- CNC—Center for Neuroscience and Cell Biology, University of Coimbra, 3004-535 Coimbra, Portugal
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Moreno MJ, Loura LMS, Martins J, Salvador A, Velazquez-Campoy A. Analysis of the Equilibrium Distribution of Ligands in Heterogeneous Media–Approaches and Pitfalls. Int J Mol Sci 2022; 23:ijms23179757. [PMID: 36077155 PMCID: PMC9478965 DOI: 10.3390/ijms23179757] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 08/23/2022] [Accepted: 08/24/2022] [Indexed: 12/02/2022] Open
Abstract
The equilibrium distribution of small molecules (ligands) between binding agents in heterogeneous media is an important property that determines their activity. Heterogeneous systems containing proteins and lipid membranes are particularly relevant due to their prevalence in biological systems, and their importance to ligand distribution, which, in turn, is crucial to ligand’s availability and biological activity. In this work, we review several approaches and formalisms for the analysis of the equilibrium distribution of ligands in the presence of proteins, lipid membranes, or both. Special attention is given to common pitfalls in the analysis, with the establishment of the validity limits for the distinct approaches. Due to its widespread use, special attention is given to the characterization of ligand binding through the analysis of Stern–Volmer plots of protein fluorescence quenching. Systems of increasing complexity are considered, from proteins with single to multiple binding sites, from ligands interacting with proteins only to biomembranes containing lipid bilayers and membrane proteins. A new formalism is proposed, in which ligand binding is treated as a partition process, while considering the saturation of protein binding sites. This formalism is particularly useful for the characterization of interaction with membrane proteins.
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Affiliation(s)
- Maria João Moreno
- Coimbra Chemistry Center—Institute of Molecular Sciences (CQC-IMS), University of Coimbra, 3004-535 Coimbra, Portugal
- Department of Chemistry, Faculty of Sciences and Technology, University of Coimbra, 3004-535 Coimbra, Portugal
- Correspondence:
| | - Luís M. S. Loura
- Coimbra Chemistry Center—Institute of Molecular Sciences (CQC-IMS), University of Coimbra, 3004-535 Coimbra, Portugal
- Faculty of Pharmacy, University of Coimbra, 3000-548 Coimbra, Portugal
| | - Jorge Martins
- Centro de Ciências do Mar (CCMAR/CIMAR, LA) and DCBB-FCT, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
| | - Armindo Salvador
- Coimbra Chemistry Center—Institute of Molecular Sciences (CQC-IMS), University of Coimbra, 3004-535 Coimbra, Portugal
- CNC—Center for Neuroscience and Cell Biology, 3004-504 Coimbra, Portugal
- Institute for Interdisciplinary Research, University of Coimbra, 3030-789 Coimbra, Portugal
| | - Adrian Velazquez-Campoy
- Institute for Biocomputation and Physics of Complex Systems (BIFI), Joint Unit GBsC-CSIC-BIFI, Universidad de Zaragoza, 50018 Zaragoza, Spain
- Departamento de Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza, 50009 Zaragoza, Spain
- Instituto de Investigación Sanitaria de Aragón (IIS Aragon), 50009 Zaragoza, Spain
- Centro de Investigación Biomédica en Red en el Área Temática de Enfermedades Hepáticas Digestivas (CIBERehd), 28029 Madrid, Spain
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Samelo J, Mora MJ, Granero GE, Moreno MJ. Partition of Amphiphilic Molecules to Lipid Bilayers by ITC: Low-Affinity Solutes. ACS OMEGA 2017; 2:6863-6869. [PMID: 31457272 PMCID: PMC6645030 DOI: 10.1021/acsomega.7b01145] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 09/25/2017] [Indexed: 05/28/2023]
Abstract
A protocol is developed to allow the accurate characterization of partition to lipid bilayers for solutes with low affinity, using isothermal titration calorimetry. The methodology proposed is suitable for studies using complex membranes, such as intact biomembranes or whole cells. In the method developed, the association is characterized at increasing solute concentrations. This allows the characterization of solute partition into unperturbed membranes, as well as effects induced by high solute concentrations. Most druglike molecules are expected to interact with low-to-moderate affinity with relevant cell membranes. This is due to both the need for a relatively high aqueous solubility of the drug and the poor binding properties of the cell membranes. The methodology is applied to characterize the interaction of antibiotic Rifampicin with 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine and with lipid bilayers representative of bacterial membranes.
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Affiliation(s)
- Jaime Samelo
- Chemistry
Department FCTUC, CQC-Biological Chemistry
Group, Largo D. Dinis,
Rua Larga, 3004-535 Coimbra, Portugal
| | - Maria Julia Mora
- Unidad
de Investigación y Desarrollo en Tecnología Farmacéutica
(UNITEFA), CONICET and Departamento de Ciencias Farmacéuticas,
Facultad de Ciencias Químicas, Universidad
Nacional de Córdoba, Ciudad Universitaria, 5000 Córdoba, Argentina
| | - Gladys Ester Granero
- Unidad
de Investigación y Desarrollo en Tecnología Farmacéutica
(UNITEFA), CONICET and Departamento de Ciencias Farmacéuticas,
Facultad de Ciencias Químicas, Universidad
Nacional de Córdoba, Ciudad Universitaria, 5000 Córdoba, Argentina
| | - Maria João Moreno
- Chemistry
Department FCTUC, CQC-Biological Chemistry
Group, Largo D. Dinis,
Rua Larga, 3004-535 Coimbra, Portugal
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Sequential reactions from catalytic hydroformylation toward the synthesis of amino compounds. Tetrahedron 2017. [DOI: 10.1016/j.tet.2017.03.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Coreta-Gomes FM, Martins PAT, Velazquez-Campoy A, Vaz WLC, Geraldes CFG, Moreno MJ. Interaction of Bile Salts with Model Membranes Mimicking the Gastrointestinal Epithelium: A Study by Isothermal Titration Calorimetry. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:9097-9104. [PMID: 26241730 DOI: 10.1021/acs.langmuir.5b01810] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Bile salts (BS) are biosurfactants synthesized in the liver and secreted into the intestinal lumen where they solubilize cholesterol and other hydrophobic compounds facilitating their gastrointestinal absorption. Partition of BS toward biomembranes is an important step in both processes. Depending on the loading of the secreted BS micelles with endogeneous cholesterol and on the amount of cholesterol from diet, this may lead to the excretion or absorption of cholesterol, from cholesterol-saturated membranes in the liver or to gastrointestinal membranes, respectively. The partition of BS toward the gastrointestinal membranes may also affect the barrier properties of those membranes affecting the permeability for hydrophobic and amphiphilic compounds. Two important parameters in the interaction of the distinct BS with biomembranes are their partition coefficient and the rate of diffusion through the membrane. Altogether, they allow the calculation of BS local concentrations in the membrane as well as their asymmetry in both membrane leaflets. The local concentration and, most importantly, its asymmetric distribution in the bilayer are a measure of induced membrane perturbation, which is expected to significantly affect its properties as a cholesterol donor and hydrophobic barrier. In this work we have characterized the partition of several BS, nonconjugated and conjugated with glycine, to large unilamellar vesicles (LUVs) in the liquid-disordered phase and with liquid-ordered/liquid-disordered phase coexistence, using isothermal titration calorimetry (ITC). The partition into the liquid-disordered bilayer was characterized by large partition coefficients and favored by enthalpy, while association with the more ordered membrane was weak and driven only by the hydrophobic effect. The trihydroxy BS partitions less efficiently toward the membranes but shows faster translocation rates, in agreement with a membrane protective effect of those BS. The rate of translocation through the more ordered membrane was faster, indicating accumulation of BS at specific locations in this membrane.
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Affiliation(s)
- Filipe M Coreta-Gomes
- Department of Chemistry, University of Coimbra , 3004-535 Coimbra, Portugal
- Coimbra Chemistry Center, University of Coimbra , 3004-535 Coimbra, Portugal
| | - Patrícia A T Martins
- Department of Chemistry, University of Coimbra , 3004-535 Coimbra, Portugal
- Coimbra Chemistry Center, University of Coimbra , 3004-535 Coimbra, Portugal
| | - Adrián Velazquez-Campoy
- Institute of Biocomputation and Physics of Complex Systems (BIFI), Joint Unit IQFR-CSIC-BIFI and Department of Biochemistry and Molecular and Cell Biology, Universidad de Zaragoza , 50018 Zaragoza, Spain
- Fundación ARAID, Diputación General de Aragón, 500018 Zaragoza, Spain
| | - Winchil L C Vaz
- Department of Chemistry, University of Coimbra , 3004-535 Coimbra, Portugal
- Coimbra Chemistry Center, University of Coimbra , 3004-535 Coimbra, Portugal
| | - Carlos F G Geraldes
- Coimbra Chemistry Center, University of Coimbra , 3004-535 Coimbra, Portugal
- Department of Life Sciences, Faculty of Science and Technology, University of Coimbra , 3001-401 Coimbra, Portugal
| | - Maria João Moreno
- Department of Chemistry, University of Coimbra , 3004-535 Coimbra, Portugal
- Coimbra Chemistry Center, University of Coimbra , 3004-535 Coimbra, Portugal
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Bastos M, Alves N, Maia S, Gomes P, Inaba A, Miyazaki Y, Zanotti JM. Hydration water and peptide dynamics – two sides of a coin. A neutron scattering and adiabatic calorimetry study at low hydration and cryogenic temperatures. Phys Chem Chem Phys 2013; 15:16693-703. [DOI: 10.1039/c3cp51937f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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