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Carabadjac I, Vormittag LC, Muszer T, Wuth J, Ulbrich MH, Heerklotz H. Transfer of ANS-Like Drugs from Micellar Drug Delivery Systems to Albumin Is Highly Favorable and Protected from Competition with Surfactant by "Reserved" Binding Sites. Mol Pharm 2024; 21:2198-2211. [PMID: 38625037 DOI: 10.1021/acs.molpharmaceut.3c00875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/17/2024]
Abstract
Micellar drug delivery systems (MDDS) for the intravenous administration of poorly soluble drugs have great advantages over alternative formulations in terms of the safety of their excipients, storage stability, and straightforward production. A classic example is mixed micelles of glycocholate (GC) and lecithin, both endogenous substances in human blood. What limits the use of MDDS is the complexity of the transitions after injection. In particular, as the MDDS disintegrate partially or completely after injection, the drug has to be transferred safely to endogenous carriers in the blood, such as human serum albumin (HSA). If this transfer is compromised, the drug might precipitate─a process that needs to be excluded under all circumstances. The key question of this paper is whether the high local concentration of GC at the moment and site of MDDS dissolution might transiently saturate HSA binding sites and, hence, endanger quick drug transfer. To address this question, we have used a new approach, which is time-resolved fluorescence spectroscopy of the single tryptophan in HSA, Trp-214, to characterize the competitive binding of GC and the drug substitute anilinonaphthalenesulfonate (ANS) to HSA. Time-resolved fluorescence of Trp-214 showed important advantages over established methods for tackling this problem. ANS has been the standard "model drug" to study albumin binding for decades, given its structural similarity to the class of naphthalene-containing acidic drugs and the fact that it is displaced from HSA by numerous drugs (which presumably bind to the same sites). Our complex global fit uses the critical approximation that the average lifetimes behave similarly to a single lifetime, but the resulting errors are found to be moderate and the results provide a convincing explanation of the, at first glance, counterintuitive behavior. Accordingly, and largely in line with the literature, we observed two types of sites binding ANS at HSA: 3 type A, rather peripheral, and 2 type B, likely more central sites. The latter quench Trp-214 by Förster Resonance Energy Transfer (FRET) with a rate constant of ≈0.4 ns-1 per ANS. Adding millimolar concentrations of GC displaces ANS from the A sites but not from B sites. At incomplete ANS saturation, this causes a GC-induced translocation of ANS from A to the more FRET-active B sites. This leads to the apparent paradox that the partial displacement of ANS from HSA increases its quenching effect on Trp-214. The most important conclusion is that (ANS-like) drugs cannot be displaced from the type-B sites, and consequently, drug transfer to these sites is not impaired by competitive binding of GC in the vicinity of a dissolving micelle. The second conclusion is that for unbound GC above the CMC (9 mM), ANS equilibrates between HSA and GC micelles but with a strong preference for free sites on HSA. That means that even persisting micelles would lose their cargo readily once exposed to HSA. For all MDDS sharing this property, targeted drug delivery approaches involving them as the nanocarrier would be pointless.
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Affiliation(s)
- Iulia Carabadjac
- Institute of Pharmaceutical Sciences, University of Freiburg, Hermann-Herder-Str. 9, 79104 Freiburg, Germany
| | - Leonie C Vormittag
- Institute of Pharmaceutical Sciences, University of Freiburg, Hermann-Herder-Str. 9, 79104 Freiburg, Germany
| | - Thomas Muszer
- Institute of Pharmaceutical Sciences, University of Freiburg, Hermann-Herder-Str. 9, 79104 Freiburg, Germany
| | - Jakob Wuth
- Institute of Pharmaceutical Sciences, University of Freiburg, Hermann-Herder-Str. 9, 79104 Freiburg, Germany
| | - Maximilian H Ulbrich
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, Albertstr. 17, 79104 Freiburg, Germany
- BIOSS Centre for Biological Signalling Studies, Schan̈zlestr. 18, Freiburg 79104, Germany
| | - Heiko Heerklotz
- Institute of Pharmaceutical Sciences, University of Freiburg, Hermann-Herder-Str. 9, 79104 Freiburg, Germany
- Leslie Dan Faculty of Pharmacy, University of Toronto, 144 College Street, Toronto M5s 3M2, Ontario, Canada
- BIOSS Centre for Biological Signalling Studies, Schan̈zlestr. 18, Freiburg 79104, Germany
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2
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Islam J, Conroy P, Fercher C, Kim M, Yaari Z, Jones M, Bell TDM, Caradoc-Davies T, Law R, Whisstock J, Heller D, Mahler S, Corrie S. Design of Polarity-Dependent Immunosensors Based on the Structural Analysis of Engineered Antibodies. ACS Chem Biol 2023; 18:1863-1871. [PMID: 37440171 DOI: 10.1021/acschembio.3c00303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
Abstract
"Reagentless" immunosensors are emerging to address the challenge of practical and sensitive detection of important biomarkers in real biological samples without the need for multistep assays and user intervention, with applications ranging from research tools to point-of-care diagnostics. Selective target binding to an affinity reagent is detected and reported in one step without the need for washing or additional reporters. In this study, we used a structure-guided approach to identify a mutation site in an antibody fragment for the polarity-dependent fluorophore, Anap, such that upon binding of the protein target cardiac troponin I, the Anap-labeled antibody would produce a detectable and dose-dependent shift in emission wavelength. We observed a significant emission wavelength shift of the Anap-labeled anti-cTnI mutant, with a blue shift of up to 37 nm, upon binding to the cTnI protein. Key differences in the resulting emission spectra between target peptides in comparison to whole proteins were also found; however, the affinity and binding characteristics remained unaffected when compared to the wild-type antibody. We also highlighted the potential flexibility of the approach by incorporating a near-infrared dye, IRDye800CW, into the same mutation site, which also resulted in a dose-dependent wavelength shift upon target incubation. These reagents can be used in experiments and devices to create simpler and more efficient biosensors across a range of research, medical laboratory, and point-of-care platforms.
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Affiliation(s)
- Jiaul Islam
- Department of Chemical and Biological Engineering, Monash University, Melbourne 3800, Australia
| | - Paul Conroy
- Dept. of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Melbourne 3800, Australia
| | - Christian Fercher
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane 4072, Australia
- ARC Training Centre for Biopharmaceutical Innovation, Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane 4072, Australia
| | - Mijin Kim
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Centre, New York 10065, United States
| | - Zvi Yaari
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Centre, New York 10065, United States
- School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91905, Israel
| | - Martina Jones
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane 4072, Australia
- ARC Training Centre for Biopharmaceutical Innovation, Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane 4072, Australia
| | - Toby D M Bell
- School of Chemistry, Monash University, Melbourne 3800, Australia
| | - Tom Caradoc-Davies
- Dept. of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Melbourne 3800, Australia
- Australian Synchrotron - ANSTO, Melbourne 3168, Australia
| | - Ruby Law
- Dept. of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Melbourne 3800, Australia
| | - James Whisstock
- Dept. of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Melbourne 3800, Australia
| | - Daniel Heller
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Centre, New York 10065, United States
| | - Stephen Mahler
- Dept. of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Melbourne 3800, Australia
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane 4072, Australia
| | - Simon Corrie
- Department of Chemical and Biological Engineering, Monash University, Melbourne 3800, Australia
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3
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Amadei M, Niro A, Fullone MR, Miele R, Polticelli F, Musci G, Bonaccorsi di Patti MC. Genetic Incorporation of Dansylalanine in Human Ferroportin to Probe the Alternating Access Mechanism of Iron Transport. Int J Mol Sci 2023; 24:11919. [PMID: 37569293 PMCID: PMC10418311 DOI: 10.3390/ijms241511919] [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: 06/23/2023] [Revised: 07/17/2023] [Accepted: 07/24/2023] [Indexed: 08/13/2023] Open
Abstract
Ferroportin (Fpn), a member of the major facilitator superfamily (MFS) of transporters, is the only known iron exporter found in mammals and plays a crucial role in regulating cellular and systemic iron levels. MFSs take on different conformational states during the transport cycle: inward open, occluded, and outward open. However, the precise molecular mechanism of iron translocation by Fpn remains unclear, with conflicting data proposing different models. In this work, amber codon suppression was employed to introduce dansylalanine (DA), an environment-sensitive fluorescent amino acid, into specific positions of human Fpn (V46, Y54, V161, Y331) predicted to undergo major conformational changes during metal translocation. The results obtained indicate that different mutants exhibit distinct fluorescence spectra depending on the position of the fluorophore within the Fpn structure, suggesting that different local environments can be probed. Cobalt titration experiments revealed fluorescence quenching and blue-shifts of λmax in Y54DA, V161DA, and Y331DA, while V46DA exhibited increased fluorescence and blue-shift of λmax. These observations suggest metal-induced conformational transitions, interpreted in terms of shifts from an outward-open to an occluded conformation. Our study highlights the potential of genetically incorporating DA into Fpn, enabling the investigation of conformational changes using fluorescence spectroscopy. This approach holds great promise for the study of the alternating access mechanism of Fpn and advancing our understanding of the molecular basis of iron transport.
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Affiliation(s)
- Matteo Amadei
- Department of Biochemical Sciences ‘A. Rossi Fanelli’, Sapienza University of Rome, 00185 Rome, Italy; (M.A.); (M.R.F.); (R.M.)
| | - Antonella Niro
- Department of Biosciences and Territory, University of Molise, 86090 Pesche, Italy; (A.N.); (G.M.)
| | - Maria Rosaria Fullone
- Department of Biochemical Sciences ‘A. Rossi Fanelli’, Sapienza University of Rome, 00185 Rome, Italy; (M.A.); (M.R.F.); (R.M.)
| | - Rossella Miele
- Department of Biochemical Sciences ‘A. Rossi Fanelli’, Sapienza University of Rome, 00185 Rome, Italy; (M.A.); (M.R.F.); (R.M.)
| | | | - Giovanni Musci
- Department of Biosciences and Territory, University of Molise, 86090 Pesche, Italy; (A.N.); (G.M.)
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Zaragoza JPT, Offenbacher AR, Hu S, Gee CL, Firestein ZM, Minnetian N, Deng Z, Fan F, Iavarone AT, Klinman JP. Temporal and spatial resolution of distal protein motions that activate hydrogen tunneling in soybean lipoxygenase. Proc Natl Acad Sci U S A 2023; 120:e2211630120. [PMID: 36867685 PMCID: PMC10013837 DOI: 10.1073/pnas.2211630120] [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: 07/06/2022] [Accepted: 01/27/2023] [Indexed: 03/05/2023] Open
Abstract
The enzyme soybean lipoxygenase (SLO) provides a prototype for deep tunneling mechanisms in hydrogen transfer catalysis. This work combines room temperature X-ray studies with extended hydrogen-deuterium exchange experiments to define a catalytically-linked, radiating cone of aliphatic side chains that connects an active site iron center of SLO to the protein-solvent interface. Employing eight variants of SLO that have been appended with a fluorescent probe at the identified surface loop, nanosecond fluorescence Stokes shifts have been measured. We report a remarkable identity of the energies of activation (Ea) for the Stokes shifts decay rates and the millisecond C-H bond cleavage step that is restricted to side chain mutants within an identified thermal network. These findings implicate a direct coupling of distal protein motions surrounding the exposed fluorescent probe to active site motions controlling catalysis. While the role of dynamics in enzyme function has been predominantly attributed to a distributed protein conformational landscape, the presented data implicate a thermally initiated, cooperative protein reorganization that occurs on a timescale faster than nanosecond and represents the enthalpic barrier to the reaction of SLO.
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Affiliation(s)
- Jan Paulo T. Zaragoza
- California Institute for Quantitative Biosciences, University of California Berkeley, Berkeley, CA94720
- Department of Chemistry, University of California Berkeley, Berkeley, CA94720
| | - Adam R. Offenbacher
- California Institute for Quantitative Biosciences, University of California Berkeley, Berkeley, CA94720
- Department of Chemistry, University of California Berkeley, Berkeley, CA94720
- Department of Chemistry, East Carolina University, Greenville, NC27858
| | - Shenshen Hu
- California Institute for Quantitative Biosciences, University of California Berkeley, Berkeley, CA94720
- Department of Chemistry, University of California Berkeley, Berkeley, CA94720
| | - Christine L. Gee
- California Institute for Quantitative Biosciences, University of California Berkeley, Berkeley, CA94720
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA94720
| | | | - Natalie Minnetian
- Department of Chemistry, University of California Berkeley, Berkeley, CA94720
| | - Zhenyu Deng
- Department of Chemistry, University of California Berkeley, Berkeley, CA94720
| | - Flora Fan
- Department of Chemistry, University of California Berkeley, Berkeley, CA94720
| | - Anthony T. Iavarone
- California Institute for Quantitative Biosciences, University of California Berkeley, Berkeley, CA94720
- Department of Chemistry, University of California Berkeley, Berkeley, CA94720
| | - Judith P. Klinman
- California Institute for Quantitative Biosciences, University of California Berkeley, Berkeley, CA94720
- Department of Chemistry, University of California Berkeley, Berkeley, CA94720
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA94720
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5
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Pang Z, Sokolov M, Kubař T, Elstner M. Unravelling the mechanism of glucose binding in a protein-based fluorescence probe: molecular dynamics simulation with a tailor-made charge model. Phys Chem Chem Phys 2022; 24:2441-2453. [PMID: 35019922 DOI: 10.1039/d1cp03733a] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Fluorophores linked to the glucose/galactose-binding protein (GGBP) are a promising class of glucose sensors with potential application in medical devices for diabetes patients. Several different fluorophores at different positions in the protein were tested experimentally so far, but a deeper molecular understanding of their function is still missing. In this work, we use molecular dynamics simulations to investigate the mechanism of glucose binding in the GGBP-Badan triple mutant and make a comparison to the GGBP wild-type protein. The aim is to achieve a detailed molecular understanding of changes in the glucose binding site due to the mutations and their effect on glucose binding. Free simulations give an insight into the changes of the hydrogen-bonding network in the active site and into the mechanisms of glucose binding. Additionally, metadynamics simulations for wild type and mutant unravel the energetics of binding/unbinding in these proteins. Computed free energies for the opening of the binding pocket for the wild-type and the mutant agree well with the experimental data. Further, the simulations also give an insight into the changes of the chromophore conformations upon glucose binding, which can help to understand fluorescence changes. Therefore, the molecular details unravelled in this work may support effective optimisation strategies for the construction of more efficient glucose sensors.
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Affiliation(s)
- Ziwei Pang
- Institute of Physical Chemistry, Karlsruhe Institute of Technology (KIT), Kaiserstr. 12, 76131 Karlsruhe, Germany.
| | - Monja Sokolov
- Institute of Physical Chemistry, Karlsruhe Institute of Technology (KIT), Kaiserstr. 12, 76131 Karlsruhe, Germany.
| | - Tomáš Kubař
- Institute of Physical Chemistry, Karlsruhe Institute of Technology (KIT), Kaiserstr. 12, 76131 Karlsruhe, Germany.
| | - Marcus Elstner
- Institute of Physical Chemistry, Karlsruhe Institute of Technology (KIT), Kaiserstr. 12, 76131 Karlsruhe, Germany. .,Institute of Biological Interfaces (IBG-2), Karlsruhe Institute of Technology (KIT), Kaiserstr. 12, 76131 Karlsruhe, Germany
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6
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Pospíšil P, Cwiklik L, Sýkora J, Hof M, Greetham GM, Towrie M, Vlček A. Solvent-Dependent Excited-State Evolution of Prodan Dyes. J Phys Chem B 2021; 125:13858-13867. [PMID: 34914398 DOI: 10.1021/acs.jpcb.1c09030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Excited-state character and dynamics of two 6-(dimethylamino)-2-acylnaphthalene dyes (Prodan and Badan-SCH2CH2OH) were studied by picosecond time-resolved IR spectroscopy (TRIR) in solvents of different polarity and relaxation times: hexane, CD3OD, and glycerol-d8. In all these solvents, near-UV excitation initially produced the same S1(ππ*) excited state characterized by a broad TRIR signal. A very fast decay (3, ∼100 ps) followed in hexane, whereas conversion to a distinct IR spectrum with a ν(C═O) band downshifted by 76 cm-1 occurred in polar/H-bonding solvents, slowing down on going from CD3OD (1, 23 ps) to glycerol-d8 (5.5, 51, 330 ps). The final relaxed excited state was assigned as planar Me2N → C═O intramolecular charge transfer S1(ICT) by comparing experimental and TDDFT-calculated spectra. TRIR conversion kinetics are comparable to those of early stages of multiexponential fluorescence decay and dynamic fluorescence red-shift. This work presents a strong evidence that Prodan-type dyes undergo solvation-driven charge separation in their S1 state, which is responsible for the dynamic fluorescence Stokes shift observed in polar/H-bonding solvents. The time evolution of the optically prepared S1(ππ*) state to the S1(ICT) final state reflects environment relaxation and solvation dynamics. This finding rationalizes the widespread use of Prodan-type dyes as probes of environment dynamics and polarity.
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Affiliation(s)
- Petr Pospíšil
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, CZ-18223 Prague, Czech Republic
| | - Lukasz Cwiklik
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, CZ-18223 Prague, Czech Republic
| | - Jan Sýkora
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, CZ-18223 Prague, Czech Republic
| | - Martin Hof
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, CZ-18223 Prague, Czech Republic
| | - Gregory M Greetham
- Central Laser Facility, Research Complex at Harwell, STFC, Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - Michael Towrie
- Central Laser Facility, Research Complex at Harwell, STFC, Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - Antonín Vlček
- J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, CZ-18223 Prague, Czech Republic.,Department of Chemistry, Queen Mary University of London, E1 4NS London, United Kingdom
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Rybicka-Jasińska K, Espinoza EM, Clark JA, Derr JB, Carlos G, Morales M, Billones MK, O'Mari O, Ågren H, Baryshnikov GV, Vullev VI. Making Nitronaphthalene Fluoresce. J Phys Chem Lett 2021; 12:10295-10303. [PMID: 34653339 PMCID: PMC8800371 DOI: 10.1021/acs.jpclett.1c02155] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Nitroaromatic compounds are inherently nonfluorescent, and the subpicosecond lifetimes of the singlet excited states of many small nitrated polycyclic aromatic hydrocarbons, such as nitronaphthalenes, render them unfeasible for photosensitizers and photo-oxidants, despite their immensely beneficial reduction potentials. This article reports up to a 7000-fold increase in the singlet-excited-state lifetime of 1-nitronaphthalene upon attaching an amine or an N-amide to the ring lacking the nitro group. Varying the charge-transfer (CT) character of the excited states and the medium polarity balances the decay rates along the radiative and the two nonradiative pathways and can make these nitronaphthalene derivatives fluoresce. The strong electron-donating amine suppresses intersystem crossing (ISC) but accommodates CT pathways of nonradiate deactivation. Conversely, the N-amide does not induce a pronounced CT character but slows down ISC enough to achieve relatively long lifetimes of the singlet excited state. These paradigms are key for the pursuit of electron-deficient (n-type) organic conjugates with promising optical characteristics.
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Affiliation(s)
| | - Eli M Espinoza
- Department of Chemistry, University of California, Riverside, California 92521, United States
| | - John A Clark
- Department of Bioengineering, University of California, Riverside, California 92521, United States
| | - James B Derr
- Department of Biochemistry, University of California, Riverside, California 92521, United States
| | - Gregory Carlos
- Department of Biology, University of California, Riverside, California 92521, United States
| | - Maryann Morales
- Department of Chemistry, University of California, Riverside, California 92521, United States
| | - Mimi Karen Billones
- Department of Biology, University of California, Riverside, California 92521, United States
| | - Omar O'Mari
- Department of Bioengineering, University of California, Riverside, California 92521, United States
| | - Hans Ågren
- Department of Physics and Astronomy, Uppsala University, SE-751 20 Uppsala, Sweden
| | - Glib V Baryshnikov
- Laboratory of Organic Electronics, Department of Science and Technology, Linköping University, SE-60174 Norrköping, Sweden
| | - Valentine I Vullev
- Department of Bioengineering, University of California, Riverside, California 92521, United States
- Department of Chemistry, University of California, Riverside, California 92521, United States
- Department of Biochemistry, University of California, Riverside, California 92521, United States
- Materials Science and Engineering Program, University of California, Riverside, California 92521, United States
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8
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Photophysical Properties of BADAN Revealed in the Study of GGBP Structural Transitions. Int J Mol Sci 2021; 22:ijms222011113. [PMID: 34681772 PMCID: PMC8540541 DOI: 10.3390/ijms222011113] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 10/06/2021] [Accepted: 10/09/2021] [Indexed: 01/14/2023] Open
Abstract
The fluorescent dye BADAN (6-bromoacetyl-2-dimetylaminonaphtalene) is widely used in various fields of life sciences, however, the photophysical properties of BADAN are not fully understood. The study of the spectral properties of BADAN attached to a number of mutant forms of GGBP, as well as changes in its spectral characteristics during structural changes in proteins, allowed to shed light on the photophysical properties of BADAN. It was shown that spectral properties of BADAN are determined by at least one non-fluorescent and two fluorescent isomers with overlapping absorbing bands. It was found that BADAN fluorescence is determined by the unsolvated "PICT" (planar intramolecular charge transfer state) and solvated "TICT" (twisted intramolecular charge transfer state) excited states. While "TICT" state can be formed both as a result of the "PICT" state solvation and as a result of light absorption by the solvated ground state of the dye. BADAN fluorescence linked to GGBP/H152C apoform is quenched by Trp 183, but this effect is inhibited by glucose intercalation. New details of the changes in the spectral characteristics of BADAN during the unfolding of the protein apo and holoforms have been obtained.
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Abstract
Fluorescence spectroscopy and microscopy are non-destructive methods that provide real-time measurements of ion channel structural dynamics. As such, they constitute a direct path linking the high-resolution structural models from X-ray crystallography and cryo-electron microscopy with the high-resolution functional data from ionic current measurements. The utility of fluorescence as a reporter of channel structure is limited by the palette of available fluorophores. Thiol-reactive fluorophores are small and bright, but are restricted in terms of the positions on a protein that can be labeled and present significant issues with background incorporation. Genetically encoded fluorescent protein tags are specific to a protein of interest, but are very large and usually only used to label the free N- and C-termini of proteins. L-3-(6-acetylnaphthalen-2-ylamino)-2-aminopropionic acid (ANAP) is a fluorescent amino acid that can be specifically incorporated into virtually any site on a protein of interest using amber stop-codon suppression. Due to its environmental sensitivity and potential as a donor in fluorescence resonance energy transfer experiments, it has been adopted by numerous investigators to study voltage, ligand, and temperature-dependent activation of a host of ion channels. Simultaneous measurements of ionic currents and ANAP fluorescence yield exceptional mechanistic insights into channel function. In this chapter, I will summarize the current literature regarding ANAP and ion channels and discuss the practical aspects of using ANAP, including potential pitfalls and confounds.
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10
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Parihar A, Shrivastava R, Dube A. Interaction of Cp6-his and Cp6 with bovine serum albumin and liver microsomes: Spectroscopic and molecular docking studies. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY 2021. [DOI: 10.1016/j.jpap.2020.100013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
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11
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Au HW, Tsang MW, Chen YW, So PK, Wong KY, Leung YC. BADAN-conjugated β-lactamases as biosensors for β-lactam antibiotic detection. PLoS One 2020; 15:e0241594. [PMID: 33125437 PMCID: PMC7598492 DOI: 10.1371/journal.pone.0241594] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 10/16/2020] [Indexed: 11/19/2022] Open
Abstract
β-Lactam antibiotic detection has significant implications in food safety control, environmental monitoring and pharmacokinetics study. Here, we report the development of two BADAN-conjugated β-lactamases, E166Cb and E166Cb/N170Q, as sensitive biosensors for β-lactam antibiotic detection. These biosensors were constructed by coupling an environment-sensitive BADAN probe onto location 166 at the active site of the PenP β-lactamase E166C and E166C/N170Q mutants. They gave fluorescence turn-on signals in response to β-lactam antibiotics. Molecular dynamics simulation of E166Cb suggested that the turn-on signal might be attributed to a polarity change of the microenvironment of BADAN and the removal of the fluorescence quenching effect on BADAN exerted by a nearby Tyr-105 upon the antibiotic binding. In the detection of four β-lactams (penicillin G, penicillin V, cefotaxime and moxalactam), both E166Cb and E166Cb/N170Q delivered signal outputs in an antibiotic-concentration dependent manner with a dynamic range spanning from 10 nM to 1 μM. Compared to E166Cb, E166Cb/N170Q generally exhibited more stable signals owing to its higher deficiency in hydrolyzing the antibiotic analyte. The overall biosensor performance of E166Cb and E166Cb/N170Q was comparable to that of their respective fluorescein-modified counterparts, E166Cf and E166Cf/N170Q. But comparatively, the BADAN-conjugated enzymes showed a higher sensitivity, displayed a faster response in detecting moxalactam and a more stable fluorescence signals towards penicillin G. This study illustrates the potential of BADAN-conjugated β-lactamases as biosensing devices for β-lactam antibiotics.
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Affiliation(s)
- Ho-Wah Au
- Department of Applied Biology and Chemical Technology, State Key Laboratory of Chemical Biology and Drug Discovery, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Man-Wah Tsang
- Department of Applied Biology and Chemical Technology, State Key Laboratory of Chemical Biology and Drug Discovery, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Yu Wai Chen
- Department of Applied Biology and Chemical Technology, State Key Laboratory of Chemical Biology and Drug Discovery, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Pui-Kin So
- Department of Applied Biology and Chemical Technology, State Key Laboratory of Chemical Biology and Drug Discovery, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Kwok-Yin Wong
- Department of Applied Biology and Chemical Technology, State Key Laboratory of Chemical Biology and Drug Discovery, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
- * E-mail: (KYW); (YCL)
| | - Yun-Chung Leung
- Department of Applied Biology and Chemical Technology, State Key Laboratory of Chemical Biology and Drug Discovery, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
- Lo Ka Chung Research Centre for Natural Anti-Cancer Drug Development, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
- * E-mail: (KYW); (YCL)
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12
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Wolf A, Dragelj J, Wonneberg J, Stellmacher J, Balke J, Woelke AL, Hodoscek M, Knapp EW, Alexiev U. The redox-coupled proton-channel opening in cytochrome c oxidase. Chem Sci 2020. [DOI: 10.1039/c9sc06463j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The interplay of cytochrome c oxidase's cofactor electrostatics, long-range conformational changes, H-bond rearrangement, and water dynamics enables transient proton-channel activation.
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Affiliation(s)
- Alexander Wolf
- Physics Department
- Freie Universität Berlin
- 14195 Berlin
- Germany
| | - Jovan Dragelj
- Institute of Chemistry and Biochemistry
- Freie Universität Berlin
- 14195 Berlin
- Germany
| | | | | | - Jens Balke
- Physics Department
- Freie Universität Berlin
- 14195 Berlin
- Germany
| | - Anna Lena Woelke
- Institute of Chemistry and Biochemistry
- Freie Universität Berlin
- 14195 Berlin
- Germany
- Department of Chemistry
| | - Milan Hodoscek
- Institute of Chemistry and Biochemistry
- Freie Universität Berlin
- 14195 Berlin
- Germany
- National Institute of Chemistry
| | - Ernst Walter Knapp
- Institute of Chemistry and Biochemistry
- Freie Universität Berlin
- 14195 Berlin
- Germany
| | - Ulrike Alexiev
- Physics Department
- Freie Universität Berlin
- 14195 Berlin
- Germany
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13
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Guo Y, Qin P, Wang C, Pan X, Dong X, Zong W. Characterization on the toxic mechanism of two fluoroquinolones to trypsin by spectroscopic and computational methods. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART. B, PESTICIDES, FOOD CONTAMINANTS, AND AGRICULTURAL WASTES 2019; 55:230-238. [PMID: 31679438 DOI: 10.1080/03601234.2019.1685317] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Ciprofloxacin (CPFX) and enrofloxacin (ENFX), two of the most widely used fluoroquinolones (FQs), pose a great threat to humans and the ecosystem. In this study, the toxic mechanisms between the two FQs and trypsin were evaluated by means of multiple spectroscopic methods, as well as molecular docking. During the fluorescence investigations, both FQs quenched the intrinsic fluorescence of trypsin effectively, which was due to the formation of moderately strong complexes (mainly through van der Waals forces and hydrogen bonds). The binding of two FQs not only caused the conformational and micro-environmental changes of trypsin, but also changed its molecular activity; shown by the UV-Visible absorption spectroscopy, synchronous fluorescence spectroscopy, and functional tests. The established methods in this work can help to comprehensively understand the transport of FQs in the human body.
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Affiliation(s)
- Yanxiu Guo
- Shandong Provincial Key Laboratory of Water and Soil Conservation and Environmental Protection, School of Resource and Environmental Sciences, Linyi University, Linyi, P.R. China
| | - Pengfei Qin
- Shandong Provincial Key Laboratory of Water and Soil Conservation and Environmental Protection, School of Resource and Environmental Sciences, Linyi University, Linyi, P.R. China
| | - Chaoyun Wang
- Shandong Provincial Key Laboratory of Water and Soil Conservation and Environmental Protection, School of Resource and Environmental Sciences, Linyi University, Linyi, P.R. China
| | - Xingren Pan
- School of Physics and Electronic Engineering, Linyi University, Linyi, P.R. China
| | - Xiaofei Dong
- Shandong Provincial Key Laboratory of Water and Soil Conservation and Environmental Protection, School of Resource and Environmental Sciences, Linyi University, Linyi, P.R. China
| | - Wansong Zong
- College of Population, Resources and Environment, Shandong Normal University, Jinan, P.R. China
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14
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Islam J, Riley BT, Fercher C, Jones ML, Buckle AM, Howard CB, Cox RP, Bell TDM, Mahler S, Corrie SR. Wavelength-Dependent Fluorescent Immunosensors via Incorporation of Polarity Indicators near the Binding Interface of Antibody Fragments. Anal Chem 2019; 91:7631-7638. [DOI: 10.1021/acs.analchem.9b00445] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jiaul Islam
- Department of Chemical Engineering, ARC Centre of Excellence in Convergent BioNano Science and Technology, Monash University, Clayton VIC 3800, Australia
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, St Lucia QLD 4072, Australia
| | - Blake T. Riley
- Dept. of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton VIC 3800, Australia
| | - Christian Fercher
- Department of Chemical Engineering, ARC Centre of Excellence in Convergent BioNano Science and Technology, Monash University, Clayton VIC 3800, Australia
- ARC Training Centre for Biopharmaceutical Innovation, Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, St Lucia QLD 4072, Australia
| | - Martina L. Jones
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, St Lucia QLD 4072, Australia
- ARC Training Centre for Biopharmaceutical Innovation, Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, St Lucia QLD 4072, Australia
| | - Ashley M. Buckle
- Dept. of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton VIC 3800, Australia
| | - Christopher B. Howard
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, St Lucia QLD 4072, Australia
- ARC Training Centre for Biopharmaceutical Innovation, Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, St Lucia QLD 4072, Australia
| | - Rosalind P. Cox
- School of Chemistry, Monash University, Clayton VIC 3800, Australia
| | - Toby D. M. Bell
- School of Chemistry, Monash University, Clayton VIC 3800, Australia
| | - Stephen Mahler
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, St Lucia QLD 4072, Australia
- ARC Training Centre for Biopharmaceutical Innovation, Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, St Lucia QLD 4072, Australia
| | - Simon R. Corrie
- Department of Chemical Engineering, ARC Centre of Excellence in Convergent BioNano Science and Technology, Monash University, Clayton VIC 3800, Australia
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, St Lucia QLD 4072, Australia
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15
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Tres F, Hall SD, Mohutsky MA, Taylor LS. Monitoring the Phase Behavior of Supersaturated Solutions of Poorly Water-Soluble Drugs Using Fluorescence Techniques. J Pharm Sci 2018; 107:94-102. [DOI: 10.1016/j.xphs.2017.10.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 09/19/2017] [Accepted: 10/03/2017] [Indexed: 01/11/2023]
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16
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Yang Y, Li D, Li C, Liu Y, Jiang K. Hydrogen bond strengthening induces fluorescence quenching of PRODAN derivative by turning on twisted intramolecular charge transfer. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2017; 187:68-74. [PMID: 28654834 DOI: 10.1016/j.saa.2017.06.029] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 06/21/2017] [Accepted: 06/22/2017] [Indexed: 06/07/2023]
Abstract
Researchers have proposed different effective mechanisms of hydrogen bonding (HB) on the fluorescence of 6-propionyl-2-dimethylaminonaphthalene (PRODAN) and its derivatives. Herein, excited state transition and dynamics analysis confirm that the fluorescence of PD (a derivative of PRODAN with ethyl replaced by 3-hydroxy-2,2-dimethylpropan) emits from the planar intramolecular charge transfer (PICT) state rather than twist ICT (TICT) state, because the fluorescence emission and surface hopping from the TICT state to the twist ground (T-S0) state is energy forbidden. Nevertheless, the strengthening of intramolecular-HB (intra-HB) and intermolecular-HB (inter-HB) of PD-(methanol)2 smooth the pathway of surface hopping from TICT to T-S0 state and the external conversion going to planar ground state by decreasing the energy difference of the two states. This smoothing changes the fluorescence state of PD-(methanol)2 to the TICT state in which fluorescence emission does not occur but surface hopping, leading to the partial fluorescence quenching of PD in methanol solvent. This conclusion is different from previous related reports. Moreover, the inter-HB strengthening of PD-methanol in PICT state induces the cleavage of intra-HB and a fluorescence red-shift of 54nm compared to PD. This red-shift increases to 66nm for PD-(methanol)2 for the strengthening of the one intra-HB and two inter-HBs. The dipole moments of PD-methanol and PD-(methanol)2 respectively increase about 10.3D and 8.1D in PICT state compared to PD. The synergistic effect of intra-HB and inter-HB induces partial quenching of PD in methanol solvent by turning on the TICT state and fluorescence red-shift. This work gives a reasonable description on the fluorescence red-shift and partial quenching of PD in methanol solvent, which will bring insight into the study of spectroscopic properties of molecules owning better spectral characteristics.
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Affiliation(s)
- Yonggang Yang
- College of Physics and Materials Science, Henan Normal University, Xinxiang 453007, China
| | - Donglin Li
- College of Physics and Materials Science, Henan Normal University, Xinxiang 453007, China
| | - Chaozheng Li
- College of Physics and Materials Science, Henan Normal University, Xinxiang 453007, China
| | - YuFang Liu
- College of Physics and Materials Science, Henan Normal University, Xinxiang 453007, China.
| | - Kai Jiang
- School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang 453007, China
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17
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Ducharme J, Auclair K. Use of bioconjugation with cytochrome P450 enzymes. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2017. [PMID: 28625736 DOI: 10.1016/j.bbapap.2017.06.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Bioconjugation, defined as chemical modification of biomolecules, is widely employed in biological and biophysical studies. It can expand functional diversity and enable applications ranging from biocatalysis, biosensing and even therapy. This review summarizes how chemical modifications of cytochrome P450 enzymes (P450s or CYPs) have contributed to improving our understanding of these enzymes. Genetic modifications of P450s have also proven very useful but are not covered in this review. Bioconjugation has served to gain structural information and investigate the mechanism of P450s via photoaffinity labeling, mechanism-based inhibition (MBI) and fluorescence studies. P450 surface acetylation and protein cross-linking have contributed to the investigation of protein complexes formation involving P450 and its redox partner or other P450 enzymes. Finally, covalent immobilization on polymer surfaces or electrodes has benefited the areas of biocatalysis and biosensor design. This article is part of a Special Issue entitled: Cytochrome P450 biodiversity and biotechnology, edited by Erika Plettner, Gianfranco Gilardi, Luet Wong, Vlada Urlacher, Jared Goldstone.
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Affiliation(s)
- Julie Ducharme
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec H3A 0B8, Canada
| | - Karine Auclair
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec H3A 0B8, Canada.
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18
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Kaushik S, Prokop Z, Damborsky J, Chaloupkova R. Kinetics of binding of fluorescent ligands to enzymes with engineered access tunnels. FEBS J 2016; 284:134-148. [DOI: 10.1111/febs.13957] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 09/30/2016] [Accepted: 11/04/2016] [Indexed: 12/22/2022]
Affiliation(s)
- Shubhangi Kaushik
- Loschmidt Laboratories Department of Experimental Biology Research Centre for Toxic Compounds in the Environment (RECETOX) Masaryk University Brno Czech Republic
| | - Zbynek Prokop
- Loschmidt Laboratories Department of Experimental Biology Research Centre for Toxic Compounds in the Environment (RECETOX) Masaryk University Brno Czech Republic
- International Clinical Research Center St. Anne's University Hospital Brno Czech Republic
| | - Jiri Damborsky
- Loschmidt Laboratories Department of Experimental Biology Research Centre for Toxic Compounds in the Environment (RECETOX) Masaryk University Brno Czech Republic
- International Clinical Research Center St. Anne's University Hospital Brno Czech Republic
| | - Radka Chaloupkova
- Loschmidt Laboratories Department of Experimental Biology Research Centre for Toxic Compounds in the Environment (RECETOX) Masaryk University Brno Czech Republic
- International Clinical Research Center St. Anne's University Hospital Brno Czech Republic
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19
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Sheu SY, Schlag EW, Yang DY. A model for ultra-fast charge transport in membrane proteins. Phys Chem Chem Phys 2016; 17:23088-94. [PMID: 26274051 DOI: 10.1039/c5cp01442e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Isolated proteins have recently been observed to transport charge and reactivity over very long distances with extraordinary rates and near perfect efficiencies in spite of their site. This is not the case if the peptide is in water, where the efficiency of charge hopping to the next site is reduced to approximately 2%. Here, water is not an ideal solvent for charge transport. The issue at hand is how to explain such enormous charge transfer quenching in water compared to another typical medium, namely lipid. We performed molecular dynamics simulations to computationally substantiate the novel long-distance charge transfer yield of the polypeptides in lipids. This is characterized by the charge transfer persistent-distance decay constant and not by the rate, which is seldom, if ever, measured and hence not directly addressed here. This model can encompass an extremely wide range of yields over very long distances in peptides in various media. The calculations here demonstrate the good charge transport efficiency in lipids in contrast to the poor efficiency in water. The protein charge transport also exhibits a very strong anisotropic effect in lipids. The peptide secondary structure effect of charge transfer in membranes is analyzed in contrast to that in water. These results suggest that this model can be useful for the prediction of charge transfer efficiency in various environments of interest and indicate that the charge transfer is highly efficient in membrane proteins.
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Affiliation(s)
- Sheh-Yi Sheu
- Department of Life Sciences and Institute of Genome Sciences, and Institute of Biomedical Informatics, National Yang-Ming University, Taipei 112, Taiwan.
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20
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Fonin A, Kuznetsova I, Turoverov K. Spectral properties of BADAN in solutions with different polarities. J Mol Struct 2015. [DOI: 10.1016/j.molstruc.2015.01.038] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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21
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Ghisaidoobe ABT, Chung SJ. Intrinsic tryptophan fluorescence in the detection and analysis of proteins: a focus on Förster resonance energy transfer techniques. Int J Mol Sci 2014; 15:22518-38. [PMID: 25490136 PMCID: PMC4284722 DOI: 10.3390/ijms151222518] [Citation(s) in RCA: 517] [Impact Index Per Article: 51.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 11/08/2014] [Accepted: 11/18/2014] [Indexed: 12/18/2022] Open
Abstract
Förster resonance energy transfer (FRET) occurs when the distance between a donor fluorophore and an acceptor is within 10 nm, and its application often necessitates fluorescent labeling of biological targets. However, covalent modification of biomolecules can inadvertently give rise to conformational and/or functional changes. This review describes the application of intrinsic protein fluorescence, predominantly derived from tryptophan (λ EX ≈ 280 nm, λ EM ≈ 350 nm), in protein-related research and mainly focuses on label-free FRET techniques. In terms of wavelength and intensity, tryptophan fluorescence is strongly influenced by its (or the proteinlocal environment, which, in addition to fluorescence quenching, has been applied to study protein conformational changes. Intrinsic Förster resonance energy transfer (iFRET), a recently developed technique, utilizes the intrinsic fluorescence of tryptophan in conjunction with target-specific fluorescent probes as FRET donors and acceptors, respectively, for real time detection of native proteins.
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Affiliation(s)
| | - Sang J Chung
- Department of Chemistry, Dongguk University, Seoul 100-715, Korea.
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