1
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Kariev AM, Green ME. Water, Protons, and the Gating of Voltage-Gated Potassium Channels. MEMBRANES 2024; 14:37. [PMID: 38392664 PMCID: PMC10890431 DOI: 10.3390/membranes14020037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 01/17/2024] [Accepted: 01/23/2024] [Indexed: 02/24/2024]
Abstract
Ion channels are ubiquitous throughout all forms of life. Potassium channels are even found in viruses. Every cell must communicate with its surroundings, so all cells have them, and excitable cells, in particular, especially nerve cells, depend on the behavior of these channels. Every channel must be open at the appropriate time, and only then, so that each channel opens in response to the stimulus that tells that channel to open. One set of channels, including those in nerve cells, responds to voltage. There is a standard model for the gating of these channels that has a section of the protein moving in response to the voltage. However, there is evidence that protons are moving, rather than protein. Water is critical as part of the gating process, although it is hard to see how this works in the standard model. Here, we review the extensive evidence of the importance of the role of water and protons in gating these channels. Our principal example, but by no means the only example, will be the Kv1.2 channel. Evidence comes from the effects of D2O, from mutations in the voltage sensing domain, as well as in the linker between that domain and the gate, and at the gate itself. There is additional evidence from computations, especially quantum calculations. Structural evidence comes from X-ray studies. The hydration of ions is critical in the transfer of ions in constricted spaces, such as the gate region and the pore of a channel; we will see how the structure of the hydrated ion fits with the structure of the channel. In addition, there is macroscopic evidence from osmotic experiments and streaming current measurements. The combined evidence is discussed in the context of a model that emphasizes the role of protons and water in gating these channels.
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Affiliation(s)
- Alisher M Kariev
- Department of Chemistry and Biochemistry, The City College of New York, New York, NY 10031, USA
| | - Michael E Green
- Department of Chemistry and Biochemistry, The City College of New York, New York, NY 10031, USA
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2
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Afshinpour M, Parsi P, Mahdiuni H. Investigation of molecular details of a bacterial cationic amino acid transporter (GkApcT) during arginine transportation using molecular dynamics simulation and umbrella sampling techniques. J Mol Model 2023; 29:260. [PMID: 37479900 DOI: 10.1007/s00894-023-05670-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 07/17/2023] [Indexed: 07/23/2023]
Abstract
CONTEXT Cationic amino acid transporters (CATs) facilitate arginine transport across membranes and maintain its levels in various tissues and organs, but their overexpression has been associated with severe cancers. A recent study identified the alternating access mechanism and critical residues involved in arginine transportation in a cationic amino acid transporter from Geobacillus kaustophilus (GkApcT). Here, we used molecular dynamics (MD) simulation methods to investigate the transportation mechanism of arginine (Arg) through GkApcT. The results revealed that arginine strongly interacts with specific binding site residues (Thr43, Asp111, Glu115, Lys191, Phe231, Ile234, and Asp237). Based on the umbrella sampling, the main driving force for arginine transport is the polar interactions of the arginine with channel-lining residues. An in-depth description of the dissociation mechanism and binding energy analysis brings valuable insight into the interactions between arginine and transporter residues, facilitating the design of effective CAT inhibitors in cancer cells. METHODS The membrane-protein system was constructed by uploading the prokaryotic CAT (PDB ID: 6F34) to the CHARMM-GUI web server. Molecular dynamics simulations were done using the GROMACS package, version 5.1.4, with the CHARMM36 force field and TIP3P water model. The MM-PBSA approach was performed for determining the arginine binding free energy. Furthermore, the hotspot residues were identified through per-residue decomposition analysis. The characteristics of the channel such as bottleneck radius and channel length were analyzed using the CaverWeb 1.1 web server. The proton wire inside the transporter was investigated based on the classic Grotthuss mechanism. We also investigated the atomistic details of arginine transportation using the path-based free energy umbrella sampling technique (US).
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Affiliation(s)
- Maral Afshinpour
- Bioinformatics Lab, Department of Biology, School of Sciences, Razi University, P.O. Box, Kermanshah, 67149-67346, Iran
- Department of Chemistry and Biochemistry, South Dakota State University (SDSU), Brookings, SD, USA
| | - Parinaz Parsi
- Bioinformatics Lab, Department of Biology, School of Sciences, Razi University, P.O. Box, Kermanshah, 67149-67346, Iran
| | - Hamid Mahdiuni
- Bioinformatics Lab, Department of Biology, School of Sciences, Razi University, P.O. Box, Kermanshah, 67149-67346, Iran.
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3
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Modeling Light-Induced Chromophore Hydration in the Reversibly Photoswitchable Fluorescent Protein Dreiklang. MOLECULES (BASEL, SWITZERLAND) 2023; 28:molecules28020505. [PMID: 36677562 PMCID: PMC9863226 DOI: 10.3390/molecules28020505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 12/30/2022] [Accepted: 01/03/2023] [Indexed: 01/06/2023]
Abstract
We report the results of a computational study of the mechanism of the light-induced chemical reaction of chromophore hydration in the fluorescent protein Dreiklang, responsible for its switching from the fluorescent ON-state to the dark OFF-state. We explore the relief of the charge-transfer excited-state potential energy surface in the ON-state to locate minimum energy conical intersection points with the ground-state energy surface. Simulations of the further evolution of model systems allow us to characterize the ground-state reaction intermediate tentatively suggested in the femtosecond studies of the light-induced dynamics in Dreiklang and finally to arrive at the reaction product. The obtained results clarify the details of the photoswitching mechanism in Dreiklang, which is governed by the chemical modification of its chromophore.
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4
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Lama B, Sarma M. Unraveling the Mechanistic Pathway for the Dual Fluorescence in Green Fluorescent Protein (GFP) Chromophore Analogue: A Detailed Theoretical Investigation. J Phys Chem B 2022; 126:9930-9944. [PMID: 36354358 DOI: 10.1021/acs.jpcb.2c03842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The photophysical properties of the para-sulfonamide (p-TsABDI) analogue of the green fluorescent protein (GFP) chromophore with both proton donating and accepting sites have been exploited in polar solvents to understand the origin of the unusual dual fluorescence nature of the chromophore. In the polar solvents, the compound undergoes structural rearrangement upon photoexcitation, leading to the ultrafast excited-state intermolecular proton transfer (ESIPT) phenomenon at the S1 surface. In this work, we employed both the static electronic structure calculations and on-the-fly molecular dynamics simulation to unravel the underlying reason for this peculiar behavior of the p-TsABDI analogue in polar solvents. To represent this adequately and provide extensive information on the ESIPT mechanism mediated by the solvent molecules, we considered explicit solvent molecules using the integral equation formalism variant of polarizable continuum (IEFPCM) model. From the static calculation analysis, we can conclude that the dual emissive behavior of the compound is ascribed to the proton transfer (PT) phenomena in the excited-state. However, based on the static calculation exclusively, it is hard to ascertain the mechanistic pathway of the PT phenomena. Hence, to investigate the dynamics and reaction mechanism for the ESIPT process, we performed the on-the-fly dynamics simulation for p-TsABDI in solvent clusters. Dynamics simulation results reveal that, based on the time lag between all the proton transfer processes, the ESIPT mechanism occurs in a stepwise manner from the benzylidene moiety of the chromophore to its imidazolinone moiety. However, the nonexistence of crossings between the S1- and S0-states confirms the PT characteristics of the reactions.
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Affiliation(s)
- Bittu Lama
- Department of Chemistry, Indian Institute of Technology, Guwahati, Assam781039, India
| | - Manabendra Sarma
- Department of Chemistry, Indian Institute of Technology, Guwahati, Assam781039, India
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5
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True-atomic-resolution insights into the structure and functional role of linear chains and low-barrier hydrogen bonds in proteins. Nat Struct Mol Biol 2022; 29:440-450. [PMID: 35484235 DOI: 10.1038/s41594-022-00762-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 03/14/2022] [Indexed: 12/21/2022]
Abstract
Hydrogen bonds are fundamental to the structure and function of biological macromolecules and have been explored in detail. The chains of hydrogen bonds (CHBs) and low-barrier hydrogen bonds (LBHBs) were proposed to play essential roles in enzyme catalysis and proton transport. However, high-resolution structural data from CHBs and LBHBs is limited. The challenge is that their 'visualization' requires ultrahigh-resolution structures of the ground and functionally important intermediate states to identify proton translocation events and perform their structural assignment. Our true-atomic-resolution structures of the light-driven proton pump bacteriorhodopsin, a model in studies of proton transport, show that CHBs and LBHBs not only serve as proton pathways, but also are indispensable for long-range communications, signaling and proton storage in proteins. The complete picture of CHBs and LBHBs discloses their multifunctional roles in providing protein functions and presents a consistent picture of proton transport and storage resolving long-standing debates and controversies.
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6
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A quantitative paradigm for water-assisted proton transport through proteins and other confined spaces. Proc Natl Acad Sci U S A 2021; 118:2113141118. [PMID: 34857630 DOI: 10.1073/pnas.2113141118] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/15/2021] [Indexed: 11/18/2022] Open
Abstract
Water-assisted proton transport through confined spaces influences many phenomena in biomolecular and nanomaterial systems. In such cases, the water molecules that fluctuate in the confined pathways provide the environment and the medium for the hydrated excess proton migration via Grotthuss shuttling. However, a definitive collective variable (CV) that accurately couples the hydration and the connectivity of the proton wire with the proton translocation has remained elusive. To address this important challenge-and thus to define a quantitative paradigm for facile proton transport in confined spaces-a CV is derived in this work from graph theory, which is verified to accurately describe water wire formation and breakage coupled to the proton translocation in carbon nanotubes and the Cl-/H+ antiporter protein, ClC-ec1. Significant alterations in the conformations and thermodynamics of water wires are uncovered after introducing an excess proton into them. Large barriers in the proton translocation free-energy profiles are found when water wires are defined to be disconnected according to the new CV, even though the pertinent confined space is still reasonably well hydrated and-by the simple measure of the mere existence of a water structure-the proton transport would have been predicted to be facile via that oversimplified measure. In this paradigm, however, the simple presence of water is not sufficient for inferring proton translocation, since an excess proton itself is able to drive hydration, and additionally, the water molecules themselves must be adequately connected to facilitate any successful proton transport.
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7
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Bertalan É, Lesca E, Schertler GFX, Bondar AN. C-Graphs Tool with Graphical User Interface to Dissect Conserved Hydrogen-Bond Networks: Applications to Visual Rhodopsins. J Chem Inf Model 2021; 61:5692-5707. [PMID: 34670076 DOI: 10.1021/acs.jcim.1c00827] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Dynamic hydrogen-bond networks provide proteins with structural plasticity required to translate signals such as ligand binding into a cellular response or to transport ions and larger solutes across membranes and, thus, are of central interest to understand protein reaction mechanisms. Here, we present C-Graphs, an efficient tool with graphical user interface that analyzes data sets of static protein structures or of independent numerical simulations to identify conserved, vs unique, hydrogen bonds and hydrogen-bond networks. For static structures, which may belong to the same protein or to proteins with different sequences, C-Graphs uses a clustering algorithm to identify sites of the hydrogen-bond network where waters are conserved among the structures. Using C-Graphs, we identify an internal protein-water hydrogen-bond network common to static structures of visual rhodopsins and adenosine A2A G protein-coupled receptors (GPCRs). Molecular dynamics simulations of a visual rhodopsin indicate that the conserved hydrogen-bond network from static structure can recruit dynamic hydrogen bonds and extend throughout most of the receptor. We release with this work the code for C-Graphs and its graphical user interface.
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Affiliation(s)
- Éva Bertalan
- Theoretical Molecular Biophysics, Department of Physics, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany
| | - Elena Lesca
- Laboratory of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institut, ETH Zürich, 5303 Villigen-PSI, Switzerland.,Department of Biology, ETH Zürich, 8093 Zürich, Switzerland
| | - Gebhard F X Schertler
- Laboratory of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institut, ETH Zürich, 5303 Villigen-PSI, Switzerland.,Department of Biology, ETH Zürich, 8093 Zürich, Switzerland
| | - Ana-Nicoleta Bondar
- Theoretical Molecular Biophysics, Department of Physics, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany.,Faculty of Physics, University of Bucharest, Strada Atomiştilor Nr. 405, Măgurele 077125, Romania.,Computational Biomedicine, IAS-5/INM-9, Institute for Neuroscience and Medicine and Institute for Advanced Simulations, Forschungszentrum Jülich, 52425 Jülich, Germany
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8
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Walker AR, Wu B, Meisner J, Fayer MD, Martínez TJ. Proton Transfer from a Photoacid to a Water Wire: First Principles Simulations and Fast Fluorescence Spectroscopy. J Phys Chem B 2021; 125:12539-12551. [PMID: 34743512 DOI: 10.1021/acs.jpcb.1c07254] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Proton transfer reactions are ubiquitous in chemistry, especially in aqueous solutions. We investigate photoinduced proton transfer between the photoacid 8-hydroxypyrene-1,3,6-trisulfonate (HPTS) and water using fast fluorescence spectroscopy and ab initio molecular dynamics simulations. Photoexcitation causes rapid proton release from the HPTS hydroxyl. Previous experiments on HPTS/water described the progress from photoexcitation to proton diffusion using kinetic equations with two time constants. The shortest time constant has been interpreted as protonated and photoexcited HPTS evolving into an "associated" state, where the proton is "shared" between the HPTS hydroxyl and an originally hydrogen bonded water. The longer time constant has been interpreted as indicating evolution to a "solvent separated" state where the shared proton undergoes long distance diffusion. In this work, we refine the previous experimental results using very pure HPTS. We then use excited state ab initio molecular dynamics to elucidate the detailed molecular mechanism of aqueous excited state proton transfer in HPTS. We find that the initial excitation results in rapid rearrangement of water, forming a strong hydrogen bonded network (a "water wire") around HPTS. HPTS then deprotonates in ≤3 ps, resulting in a proton that migrates back and forth along the wire before localizing on a single water molecule. We find a near linear relationship between the emission wavelength and proton-HPTS distance over the simulated time scale, suggesting that the emission wavelength can be used as a ruler for the proton distance. Our simulations reveal that the "associated" state corresponds to a water wire with a mobile proton and that the diffusion of the proton away from this water wire (to a generalized "solvent-separated" state) corresponds to the longest experimental time constant.
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Affiliation(s)
- Alice R Walker
- Department of Chemistry, Stanford University, Stanford, California 94305, United States.,The PULSE Institute, Stanford University, Stanford, California 94305, United States.,SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Boning Wu
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Jan Meisner
- Department of Chemistry, Stanford University, Stanford, California 94305, United States.,The PULSE Institute, Stanford University, Stanford, California 94305, United States.,SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Michael D Fayer
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Todd J Martínez
- Department of Chemistry, Stanford University, Stanford, California 94305, United States.,The PULSE Institute, Stanford University, Stanford, California 94305, United States.,SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
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9
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Christou NE, Giandoreggio-Barranco K, Ayala I, Glushonkov O, Adam V, Bourgeois D, Brutscher B. Disentangling Chromophore States in a Reversibly Switchable Green Fluorescent Protein: Mechanistic Insights from NMR Spectroscopy. J Am Chem Soc 2021; 143:7521-7530. [PMID: 33966387 DOI: 10.1021/jacs.1c02442] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The photophysical properties of fluorescent proteins, including phototransformable variants used in advanced microscopy applications, are influenced by the environmental conditions in which they are expressed and used. Rational design of improved fluorescent protein markers requires a better understanding of these environmental effects. We demonstrate here that solution NMR spectroscopy can detect subtle changes in the chemical structure, conformation, and dynamics of the photoactive chromophore moiety with atomic resolution, providing such mechanistic information. Studying rsFolder, a reversibly switchable green fluorescent protein, we have identified four distinct configurations of its p-HBI chromophore, corresponding to the cis and trans isomers, with each one either protonated (neutral) or deprotonated (anionic) at the benzylidene ring. The relative populations and interconversion kinetics of these chromophore species depend on sample pH and buffer composition that alter in a complex way the strength of H-bonds that contribute in stabilizing the chromophore within the protein scaffold. We show in particular the important role of histidine-149 in stabilizing the neutral trans chromophore at intermediate pH values, leading to ground-state cis-trans isomerization with a peculiar pH dependence. We discuss the potential implications of our findings on the pH dependence of the photoswitching contrast, a critical parameter in nanoscopy applications.
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Affiliation(s)
- Nina Eleni Christou
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale (IBS), 38000 Grenoble, France
| | | | - Isabel Ayala
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale (IBS), 38000 Grenoble, France
| | - Oleksandr Glushonkov
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale (IBS), 38000 Grenoble, France
| | - Virgile Adam
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale (IBS), 38000 Grenoble, France
| | - Dominique Bourgeois
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale (IBS), 38000 Grenoble, France
| | - Bernhard Brutscher
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale (IBS), 38000 Grenoble, France
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10
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Mechanism of ArcLight derived GEVIs involves electrostatic interactions that can affect proton wires. Biophys J 2021; 120:1916-1926. [PMID: 33744263 PMCID: PMC8204334 DOI: 10.1016/j.bpj.2021.03.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 02/28/2021] [Accepted: 03/10/2021] [Indexed: 11/24/2022] Open
Abstract
The genetically encoded voltage indicators ArcLight and its derivatives mediate voltage-dependent optical signals by intermolecular, electrostatic interactions between neighboring fluorescent proteins (FPs). A random mutagenesis event placed a negative charge on the exterior of the FP, resulting in a greater than 10-fold improvement of the voltage-dependent optical signal. Repositioning this negative charge on the exterior of the FP reversed the polarity of voltage-dependent optical signals, suggesting the presence of “hot spots” capable of interacting with the negative charge on a neighboring FP, thereby changing the fluorescent output. To explore the potential effect on the chromophore state, voltage-clamp fluorometry was performed with alternating excitation at 390 nm followed by excitation at 470 nm, resulting in several mutants exhibiting voltage-dependent, ratiometric optical signals of opposing polarities. However, the kinetics, voltage ranges, and optimal FP fusion sites were different depending on the wavelength of excitation. These results suggest that the FP has external, electrostatic pathways capable of quenching fluorescence that are wavelength specific. One mutation to the FP (E222H) showed a voltage-dependent increase in fluorescence when excited at 390 nm, indicating the ability to affect the proton wire from the protonated chromophore to the H222 position. ArcLight-derived sensors may therefore offer a novel way to map how conditions external to the β-can structure can affect the fluorescence of the chromophore and transiently affect those pathways via conformational changes mediated by manipulating membrane potential.
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11
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Coppola F, Perrella F, Petrone A, Donati G, Rega N. A Not Obvious Correlation Between the Structure of Green Fluorescent Protein Chromophore Pocket and Hydrogen Bond Dynamics: A Choreography From ab initio Molecular Dynamics. Front Mol Biosci 2020; 7:569990. [PMID: 33195416 PMCID: PMC7653547 DOI: 10.3389/fmolb.2020.569990] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 09/11/2020] [Indexed: 11/23/2022] Open
Abstract
The Green Fluorescent Protein (GFP) is a widely studied chemical system both for its large amount of applications and the complexity of the excited state proton transfer responsible of the change in the protonation state of the chromophore. A detailed investigation on the structure of the chromophore environment and the influence of chromophore form (either neutral or anionic) on it is of crucial importance to understand how these factors could potentially influence the protein function. In this study, we perform a detailed computational investigation based on the analysis of ab-initio molecular dynamics simulations, to disentangle the main structural quantities determining the fine balance in the chromophore environment. We found that specific hydrogen bonds interactions directly involving the chromophore (or not), are correlated to quantities, such as the volume of the cavity in which the chromophore is embedded and that it is importantly affected by the chromophore protonation state. The cross-correlation analysis performed on some of these hydrogen bonds and the cavity volume, demonstrates a direct correlation among them and we also identified the ones specifically involved in this correlation. We also found that specific interactions among residues far in the space are correlated, demonstrating the complexity of the chromophore environment and that many structural quantities have to be taken into account to properly describe and understand the main factors tuning the active site of the protein. From an overall evaluation of the results obtained in this work, it is shown that the residues which a priori are perceived to be spectators play instead an important role in both influencing the chromophore environment (cavity volume) and its dynamics (cross-correlations among spatially distant residues).
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Affiliation(s)
- Federico Coppola
- Department of Chemical Sciences, University of Naples Federico II, Naples, Italy
| | - Fulvio Perrella
- Department of Chemical Sciences, University of Naples Federico II, Naples, Italy
| | - Alessio Petrone
- Department of Chemical Sciences, University of Naples Federico II, Naples, Italy
| | - Greta Donati
- Department of Chemical Sciences, University of Naples Federico II, Naples, Italy
| | - Nadia Rega
- Department of Chemical Sciences, University of Naples Federico II, Naples, Italy.,Center for Advanced Biomaterials for Healthcare@CRIB, Naples, Italy
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12
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Kędzierski P, Zaczkowska M, Sokalski WA. Extreme Catalytic Power of Ketosteroid Isomerase Related to the Reversal of Proton Dislocations in Hydrogen-Bond Network. J Phys Chem B 2020; 124:3661-3666. [PMID: 32293890 PMCID: PMC7467711 DOI: 10.1021/acs.jpcb.0c01489] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
Dynamic
electrostatic catalytic field (DECF) vectors derived from
transition state and reactant wavefunctions for the two-step reaction
occurring within ketosteroid isomerase (KSI) have been calculated
using MP2/aug-cc-pVTZ and lower theory levels to determine the magnitude
of the catalytic effect and the optimal directions of proton transfers
in the KSI hydrogen-bond network. The most surprising and meaningful
finding is that the KSI catalytic activity is enhanced by proton dislocations
proceeding in opposite directions for each of the two consecutive
reaction steps in the same hydrogen network. Such a mechanism allows
an ultrafast switching of the catalytic proton wire environment, possibly
related to the exceptionally high KSI catalytic power.
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Affiliation(s)
- Paweł Kędzierski
- Department of Chemistry, Wrocław University of Science and Technology, Wyb. Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Maria Zaczkowska
- Department of Chemistry, Wrocław University of Science and Technology, Wyb. Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - W Andrzej Sokalski
- Department of Chemistry, Wrocław University of Science and Technology, Wyb. Wyspiańskiego 27, 50-370 Wrocław, Poland
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13
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Shibazaki C, Shimizu R, Kagotani Y, Ostermann A, Schrader TE, Adachi M. Direct Observation of the Protonation States in the Mutant Green Fluorescent Protein. J Phys Chem Lett 2020; 11:492-496. [PMID: 31880458 DOI: 10.1021/acs.jpclett.9b03252] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Neutron crystallography has been used to elucidate the protonation states for the enhanced green fluorescent protein, which has revolutionized imaging technologies. The structure has a deprotonated hydroxyl group in the fluorescent chromophore. Also, the protonation states of His148 and Thr203, as well as the orientation of a critical water molecule in direct contact with the chromophore, could be determined. The results demonstrate that the deprotonated hydroxyl group in the chromophore and the nitrogen atom ND1 in His148 are charged negatively and positively, respectively, forming an ion pair. The position of the two deuterium atoms in the critical water molecule appears to be displaced slightly toward the acceptor oxygen atoms according to their omit maps. This displacement implies the formation of an intriguing electrostatic potential realized inside of the protein. Our findings provide new insights into future protein design strategies along with developments in quantum chemical calculations.
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Affiliation(s)
- Chie Shibazaki
- Institute for Quantum Life Science , National Institutes for Quantum and Radiological Science and Technology (QST) , 2-4 Shirakata , Tokai , Ibaraki 319-1106 , Japan
| | - Rumi Shimizu
- Institute for Quantum Life Science , National Institutes for Quantum and Radiological Science and Technology (QST) , 2-4 Shirakata , Tokai , Ibaraki 319-1106 , Japan
| | - Yuji Kagotani
- Institute for Quantum Life Science , National Institutes for Quantum and Radiological Science and Technology (QST) , 2-4 Shirakata , Tokai , Ibaraki 319-1106 , Japan
| | - Andreas Ostermann
- Heinz Maier-Leibnitz Zentrum (MLZ) , Technische Universität München , Lichtenbergstrasse 1 , 85748 Garching , Germany
| | - Tobias E Schrader
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ) , Forschungszentrum Jülich GmbH , Lichtenbergstrasse 1 , 85748 Garching , Germany
| | - Motoyasu Adachi
- Institute for Quantum Life Science , National Institutes for Quantum and Radiological Science and Technology (QST) , 2-4 Shirakata , Tokai , Ibaraki 319-1106 , Japan
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14
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Grigorenko B, Polyakov I, Nemukhin A. Mechanisms of ATP to cAMP Conversion Catalyzed by the Mammalian Adenylyl Cyclase: A Role of Magnesium Coordination Shells and Proton Wires. J Phys Chem B 2020; 124:451-460. [PMID: 31881811 DOI: 10.1021/acs.jpcb.9b07349] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
We report a mechanism of adenosine triphosphate (ATP) to cyclic adenosine monophosphate (cAMP) conversion by the mammalian type V adenylyl cyclase revealed in molecular dynamics (MD) and quantum mechanics/molecular mechanics (QM/MM) simulations. We characterize a set of computationally derived enzyme-substrate (ES) structures showing an important role of coordination shells of magnesium ions in the solvent accessible active site. In the lowest energy ES conformation, the coordination shell of MgA2+ does not include the Oδ1 atom of the conserved Asp440 residue. Starting from this conformation, a one-step reaction mechanism is characterized that includes proton transfer from the ribose O3'H3' group in ATP to Asp440 via a shuttling water molecule concerted with PA-O3A bond cleavage and O3'-PA bond formation. The energy profile of this route is consistent with the observed reaction kinetics. The computed energy profiles initiated from higher energy ES complexes are characterized by larger energy expenses to complete the reaction. Consistent with experimental data, we show that the Asp440Ala mutant of the enzyme should exhibit a reduced but retained activity. All considered reaction pathways include proton wires from the O3'H3' group via shuttling water molecules.
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Affiliation(s)
- Bella Grigorenko
- Chemistry Department , M. V. Lomonosov Moscow State University , 1-3 Leninskiye Gory , Moscow 119991 , Russia.,N. M. Emanuel Institute of Biochemical Physics , Russian Academy of Sciences , 4 Kosygin Street , Moscow 119334 , Russia
| | - Igor Polyakov
- Chemistry Department , M. V. Lomonosov Moscow State University , 1-3 Leninskiye Gory , Moscow 119991 , Russia.,N. M. Emanuel Institute of Biochemical Physics , Russian Academy of Sciences , 4 Kosygin Street , Moscow 119334 , Russia
| | - Alexander Nemukhin
- Chemistry Department , M. V. Lomonosov Moscow State University , 1-3 Leninskiye Gory , Moscow 119991 , Russia.,N. M. Emanuel Institute of Biochemical Physics , Russian Academy of Sciences , 4 Kosygin Street , Moscow 119334 , Russia
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15
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Thomas SK, Jamieson WD, Gwyther REA, Bowen BJ, Beachey A, Worthy HL, Macdonald JE, Elliott M, Castell OK, Jones DD. Site-Specific Protein Photochemical Covalent Attachment to Carbon Nanotube Side Walls and Its Electronic Impact on Single Molecule Function. Bioconjug Chem 2020; 31:584-594. [PMID: 31743647 DOI: 10.1021/acs.bioconjchem.9b00719] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Functional integration of proteins with carbon-based nanomaterials such as nanotubes holds great promise in emerging electronic and optoelectronic applications. Control over protein attachment poses a major challenge for consistent and useful device fabrication, especially when utilizing single/few molecule properties. Here, we exploit genetically encoded phenyl azide photochemistry to define the direct covalent attachment of four different proteins, including the fluorescent protein GFP and a β-lactamase binding protein (BBP), to carbon nanotube side walls. AFM showed that on attachment BBP could still recognize and bind additional protein components. Single molecule fluorescence revealed that on attachment to SWCNTs function was retained and there was feedback to GFP in terms of fluorescence intensity and improved resistance to photobleaching; GFP is fluorescent for much longer on attachment. The site of attachment proved important in terms of electronic impact on GFP function, with the attachment site furthest from the chromophore having the larger effect on fluorescence. Our approach provides a versatile and general method for generating intimate protein-CNT hybrid bioconjugates. It can be potentially applied to any protein of choice; the attachment position and thus interface characteristics with the CNT can easily be changed by simply placing the phenyl azide chemistry at different residues by gene mutagenesis. Thus, our approach will allow consistent construction and modulate functional coupling through changing the protein attachment position.
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Affiliation(s)
- Suzanne K Thomas
- School of Physics and Astronomy, Cardiff University, Cardiff, CF24 3AA, United Kingdom
| | - W David Jamieson
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, CF10 3NB, United Kingdom
| | - Rebecca E A Gwyther
- School of Biosciences, Cardiff University, Cardiff, CF10 3AX, United Kingdom
| | - Benjamin J Bowen
- School of Biosciences, Cardiff University, Cardiff, CF10 3AX, United Kingdom
| | - Adam Beachey
- School of Physics and Astronomy, Cardiff University, Cardiff, CF24 3AA, United Kingdom
| | - Harley L Worthy
- School of Biosciences, Cardiff University, Cardiff, CF10 3AX, United Kingdom
| | - J Emyr Macdonald
- School of Physics and Astronomy, Cardiff University, Cardiff, CF24 3AA, United Kingdom
| | - Martin Elliott
- School of Physics and Astronomy, Cardiff University, Cardiff, CF24 3AA, United Kingdom
| | - Oliver K Castell
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, CF10 3NB, United Kingdom
| | - D Dafydd Jones
- School of Biosciences, Cardiff University, Cardiff, CF10 3AX, United Kingdom
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16
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Pope JR, Johnson RL, Jamieson WD, Worthy HL, Kailasam S, Ahmed RD, Taban I, Auhim HS, Watkins DW, Rizkallah PJ, Castell OK, Jones DD. Association of Fluorescent Protein Pairs and Its Significant Impact on Fluorescence and Energy Transfer. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2020; 8:2003167. [PMID: 33437587 PMCID: PMC7788595 DOI: 10.1002/advs.202003167] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Indexed: 06/01/2023]
Abstract
Fluorescent proteins (FPs) are commonly used in pairs to monitor dynamic biomolecular events through changes in proximity via distance dependent processes such as Förster resonance energy transfer (FRET). The impact of FP association is assessed by predicting dimerization sites in silico and stabilizing the dimers by bio-orthogonal covalent linkages. In each tested case dimerization changes inherent fluorescence, including FRET. GFP homodimers demonstrate synergistic behavior with the dimer being brighter than the sum of the monomers. The homodimer structure reveals the chromophores are close with favorable transition dipole alignments and a highly solvated interface. Heterodimerization (GFP with Venus) results in a complex with ≈87% FRET efficiency, significantly below the 99.7% efficiency predicted. A similar efficiency is observed when the wild-type FPs are fused to a naturally occurring protein-protein interface system. GFP complexation with mCherry results in loss of mCherry fluorescence. Thus, simple assumptions used when monitoring interactions between proteins via FP FRET may not always hold true, especially under conditions whereby the protein-protein interactions promote FP interaction.
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Affiliation(s)
- Jacob R. Pope
- Molecular BiosciencesSchool of BiosciencesCardiff UniversityCardiffCF10 3AXUK
| | - Rachel L. Johnson
- Molecular BiosciencesSchool of BiosciencesCardiff UniversityCardiffCF10 3AXUK
| | | | - Harley L. Worthy
- Molecular BiosciencesSchool of BiosciencesCardiff UniversityCardiffCF10 3AXUK
- Present address:
Henry Wellcome Building for BiocatalysisBiosciencesUniversity of ExeterExeterEX4 4QDUK
| | - Senthilkumar Kailasam
- McGill University and Genome Quebec Innovation CentreMontrealQuebecH3A 0G1Canada
- Department of Human GeneticsMcGill UniversityMontrealQuebecCanada
| | - Rochelle D. Ahmed
- Molecular BiosciencesSchool of BiosciencesCardiff UniversityCardiffCF10 3AXUK
| | - Ismail Taban
- Molecular BiosciencesSchool of BiosciencesCardiff UniversityCardiffCF10 3AXUK
| | - Husam Sabah Auhim
- Molecular BiosciencesSchool of BiosciencesCardiff UniversityCardiffCF10 3AXUK
- Department of BiologyCollege of ScienceUniversity of BaghdadBaghdadIraq
| | - Daniel W. Watkins
- Molecular BiosciencesSchool of BiosciencesCardiff UniversityCardiffCF10 3AXUK
- Present address:
School of BiochemistryUniversity of BristolBristolBS8 1QUUK
| | | | | | - D. Dafydd Jones
- Molecular BiosciencesSchool of BiosciencesCardiff UniversityCardiffCF10 3AXUK
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17
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Grigorenko BL, Polyakov IV, Krylov AI, Nemukhin AV. Computational Modeling Reveals the Mechanism of Fluorescent State Recovery in the Reversibly Photoswitchable Protein Dreiklang. J Phys Chem B 2019; 123:8901-8909. [DOI: 10.1021/acs.jpcb.9b06988] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Bella L. Grigorenko
- Department of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow 119334, Russia
| | - Igor V. Polyakov
- Department of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow 119334, Russia
| | - Anna I. Krylov
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
| | - Alexander V. Nemukhin
- Department of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow 119334, Russia
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18
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Maurer M, Oostenbrink C. Water in protein hydration and ligand recognition. J Mol Recognit 2019; 32:e2810. [PMID: 31456282 PMCID: PMC6899928 DOI: 10.1002/jmr.2810] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 07/31/2019] [Accepted: 08/01/2019] [Indexed: 12/16/2022]
Abstract
This review describes selected basics of water in biomolecular recognition. We focus on a qualitative understanding of the most important physical aspects, how these change in magnitude between bulk water and protein environment, and how the roles that water plays for proteins arise from them. These roles include mechanical support, thermal coupling, dielectric screening, mass and charge transport, and the competition with a ligand for the occupation of a binding site. The presence or absence of water has ramifications that range from the thermodynamic binding signature of a single ligand up to cellular survival. The large inhomogeneity in water density, polarity and mobility around a solute is hard to assess in experiment. This is a source of many difficulties in the solvation of protein models and computational studies that attempt to elucidate or predict ligand recognition. The influence of water in a protein binding site on the experimental enthalpic and entropic signature of ligand binding is still a point of much debate. The strong water‐water interaction in enthalpic terms is counteracted by a water molecule's high mobility in entropic terms. The complete arrest of a water molecule's mobility sets a limit on the entropic contribution of a water displacement process, while the solvent environment sets limits on ligand reactivity.
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Affiliation(s)
- Manuela Maurer
- Institute of Molecular Modeling and Simulation, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Chris Oostenbrink
- Institute of Molecular Modeling and Simulation, University of Natural Resources and Life Sciences, Vienna, Austria
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19
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Lacombat F, Espagne A, Dozova N, Plaza P, Müller P, Brettel K, Franz-Badur S, Essen LO. Ultrafast Oxidation of a Tyrosine by Proton-Coupled Electron Transfer Promotes Light Activation of an Animal-like Cryptochrome. J Am Chem Soc 2019; 141:13394-13409. [PMID: 31368699 DOI: 10.1021/jacs.9b03680] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The animal-like cryptochrome of Chlamydomonas reinhardtii (CraCRY) is a recently discovered photoreceptor that controls the transcriptional profile and sexual life cycle of this alga by both blue and red light. CraCRY has the uncommon feature of efficient formation and longevity of the semireduced neutral form of its FAD cofactor upon blue light illumination. Tyrosine Y373 plays a crucial role by elongating , as fourth member, the electron transfer (ET) chain found in most other cryptochromes and DNA photolyases, which comprises a conserved tryptophan triad. Here, we report the full mechanism of light-induced FADH• formation in CraCRY using transient absorption spectroscopy from hundreds of femtoseconds to seconds. Electron transfer starts from ultrafast reduction of excited FAD to FAD•- by the proximal tryptophan (0.4 ps) and is followed by delocalized migration of the produced WH•+ radical along the tryptophan triad (∼4 and ∼50 ps). Oxidation of Y373 by coupled ET to WH•+ and deprotonation then proceeds in ∼800 ps, without any significant kinetic isotope effect, nor a pH effect between pH 6.5 and 9.0. The FAD•-/Y373• pair is formed with high quantum yield (∼60%); its intrinsic decay by recombination is slow (∼50 ms), favoring reduction of Y373• by extrinsic agents and protonation of FAD•- to form the long-lived, red-light absorbing FADH• species. Possible mechanisms of tyrosine oxidation by ultrafast proton-coupled ET in CraCRY, a process about 40 times faster than the archetypal tyrosine-Z oxidation in photosystem II, are discussed in detail.
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Affiliation(s)
- Fabien Lacombat
- PASTEUR, Département de chimie , École normale supérieure, PSL University, Sorbonne Université, CNRS , 75005 Paris , France
| | - Agathe Espagne
- PASTEUR, Département de chimie , École normale supérieure, PSL University, Sorbonne Université, CNRS , 75005 Paris , France
| | - Nadia Dozova
- PASTEUR, Département de chimie , École normale supérieure, PSL University, Sorbonne Université, CNRS , 75005 Paris , France
| | - Pascal Plaza
- PASTEUR, Département de chimie , École normale supérieure, PSL University, Sorbonne Université, CNRS , 75005 Paris , France
| | - Pavel Müller
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS , Univ. Paris-Sud, Université Paris-Saclay , 91198 , Gif-sur-Yvette cedex , France
| | - Klaus Brettel
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS , Univ. Paris-Sud, Université Paris-Saclay , 91198 , Gif-sur-Yvette cedex , France
| | - Sophie Franz-Badur
- Department of Chemistry, Center for Synthetic Microbiology , Philipps University , 35032 Marburg , Germany
| | - Lars-Oliver Essen
- Department of Chemistry, Center for Synthetic Microbiology , Philipps University , 35032 Marburg , Germany
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20
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Worthy HL, Auhim HS, Jamieson WD, Pope JR, Wall A, Batchelor R, Johnson RL, Watkins DW, Rizkallah P, Castell OK, Jones DD. Positive functional synergy of structurally integrated artificial protein dimers assembled by Click chemistry. Commun Chem 2019. [DOI: 10.1038/s42004-019-0185-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
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21
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Takaba K, Tai Y, Eki H, Dao HA, Hanazono Y, Hasegawa K, Miki K, Takeda K. Subatomic resolution X-ray structures of green fluorescent protein. IUCRJ 2019; 6:387-400. [PMID: 31098020 PMCID: PMC6503917 DOI: 10.1107/s205225251900246x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 02/17/2019] [Indexed: 05/06/2023]
Abstract
Green fluorescent protein (GFP) is a light-emitting protein that does not require a prosthetic group for its fluorescent activity. As such, GFP has become indispensable as a molecular tool in molecular biology. Nonetheless, there has been no subatomic elucidation of the GFP structure owing to the structural polymorphism around the chromophore. Here, subatomic resolution X-ray structures of GFP without the structural polymorphism are reported. The positions of H atoms, hydrogen-bonding network patterns and accurate geometric parameters were determined for the two protonated forms. Compared with previously determined crystal structures and theoretically optimized structures, the anionic chromophores of the structures represent the authentic resonance state of GFP. In addition, charge-density analysis based on atoms-in-molecules theory and noncovalent interaction analysis highlight weak but substantial interactions between the chromophore and the protein environment. Considered with the derived chemical indicators, the lone pair-π interactions between the chromophore and Thr62 should play a sufficient role in maintaining the electronic state of the chromophore. These results not only reveal the fine structural features that are critical to understanding the properties of GFP, but also highlight the limitations of current quantum-chemical calculations.
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Affiliation(s)
- Kiyofumi Takaba
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Yang Tai
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Haruhiko Eki
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Hoang-Anh Dao
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Yuya Hanazono
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Kazuya Hasegawa
- Protein Crystal Analysis Division, Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - Kunio Miki
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Kazuki Takeda
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
- Correspondence e-mail:
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22
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Nemukhin AV, Grigorenko BL, Khrenova MG, Krylov AI. Computational Challenges in Modeling of Representative Bioimaging Proteins: GFP-Like Proteins, Flavoproteins, and Phytochromes. J Phys Chem B 2019; 123:6133-6149. [DOI: 10.1021/acs.jpcb.9b00591] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Alexander V. Nemukhin
- Department of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow 119334, Russia
| | - Bella L. Grigorenko
- Department of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow 119334, Russia
| | - Maria G. Khrenova
- Department of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
- Federal Research Center of Biotechnology, Bach Institute of Biochemistry, Russian Academy of Sciences, Moscow 119071, Russian
| | - Anna I. Krylov
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
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23
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24
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Steiert F, Petrov EP, Schultz P, Schwille P, Weidemann T. Photophysical Behavior of mNeonGreen, an Evolutionarily Distant Green Fluorescent Protein. Biophys J 2018; 114:2419-2431. [PMID: 29706225 DOI: 10.1016/j.bpj.2018.04.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 04/06/2018] [Accepted: 04/09/2018] [Indexed: 12/31/2022] Open
Abstract
Fluorescent proteins (FPs) feature complex photophysical behavior that must be considered when studying the dynamics of fusion proteins in model systems and live cells. In this work, we characterize mNeonGreen (mNG), a recently introduced FP from the bilaterian Branchiostoma lanceolatum, in comparison to the well-known hydrozoan variants enhanced green fluorescent protein (EGFP) and Aequorea coerulescens GFP by steady-state spectroscopy and fluorescence correlation spectroscopy in solutions of different pH. Blind spectral unmixing of sets of absorption spectra reveals three interconverting electronic states of mNG: a nonfluorescent protonated state, a bright state showing bell-shaped pH dependence, and a similarly bright state dominating at high pH. The gradual population of the acidic form by external protonation is reflected by increased flickering at low pH in fluorescence correlation spectroscopy measurements, albeit with much slower flicker rates and lower amplitudes as compared to Aequorea GFPs. In addition, increased flickering of mNG indicates a second deprotonation step above pH 10 leading to a slight decrease in fluorescence. Thus, mNG is distinguished from Aequorea GFPs by a two-step protonation response with opposite effects that reflects a chemically distinct chromophore environment. Despite the more complex pH dependence, mNG represents a superior FP under a broad range of conditions.
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Affiliation(s)
- Frederik Steiert
- Department of Cellular and Molecular Biophysics, Max Planck Institute of Biochemistry, Martinsried, Germany; Physics Department, Technical University Munich, Garching, Germany
| | - Eugene P Petrov
- Department of Cellular and Molecular Biophysics, Max Planck Institute of Biochemistry, Martinsried, Germany; Faculty of Physics, Ludwig Maximilian University of Munich, Munich, Germany
| | - Peter Schultz
- Department of Cellular and Molecular Biophysics, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Petra Schwille
- Department of Cellular and Molecular Biophysics, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Thomas Weidemann
- Department of Cellular and Molecular Biophysics, Max Planck Institute of Biochemistry, Martinsried, Germany.
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25
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Freeley M, Worthy HL, Ahmed R, Bowen B, Watkins D, Macdonald JE, Zheng M, Jones DD, Palma M. Site-Specific One-to-One Click Coupling of Single Proteins to Individual Carbon Nanotubes: A Single-Molecule Approach. J Am Chem Soc 2017; 139:17834-17840. [PMID: 29148737 DOI: 10.1021/jacs.7b07362] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We report the site-specific coupling of single proteins to individual carbon nanotubes (CNTs) in solution and with single-molecule control. Using an orthogonal Click reaction, Green Fluorescent Protein (GFP) was engineered to contain a genetically encoded azide group and then bound to CNT ends in different configurations: in close proximity or at longer distances from the GFP's functional center. Atomic force microscopy and fluorescence analysis in solution and on surfaces at the single-protein level confirmed the importance of bioengineering optimal protein attachment sites to achieve direct protein-nanotube communication and bridging.
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Affiliation(s)
- Mark Freeley
- School of Biological and Chemical Sciences, Institute of Bioengineering, and Materials Research Institute, Queen Mary University of London , Mile End Road, London E1 4NS, United Kingdom
| | - Harley L Worthy
- Division of Molecular Biosciences, School of Biosciences, Main Building, Cardiff University , Cardiff, Wales CF10 3AX, United Kingdom
| | - Rochelle Ahmed
- Division of Molecular Biosciences, School of Biosciences, Main Building, Cardiff University , Cardiff, Wales CF10 3AX, United Kingdom
| | - Ben Bowen
- Division of Molecular Biosciences, School of Biosciences, Main Building, Cardiff University , Cardiff, Wales CF10 3AX, United Kingdom
| | - Daniel Watkins
- Division of Molecular Biosciences, School of Biosciences, Main Building, Cardiff University , Cardiff, Wales CF10 3AX, United Kingdom
| | - J Emyr Macdonald
- School of Physics and Astronomy, Cardiff University , Queens's Building, The Parade, Cardiff CF24 3AA, United Kingdom
| | - Ming Zheng
- Materials Science and Engineering Division, National Institute of Standards and Technology , 100 Bureau Drive, Gaithersburg, Maryland 20899-8542, United States
| | - D Dafydd Jones
- Division of Molecular Biosciences, School of Biosciences, Main Building, Cardiff University , Cardiff, Wales CF10 3AX, United Kingdom
| | - Matteo Palma
- School of Biological and Chemical Sciences, Institute of Bioengineering, and Materials Research Institute, Queen Mary University of London , Mile End Road, London E1 4NS, United Kingdom
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26
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Wilson RH, Zamfir S, Sumner I. Molecular dynamics simulations reveal a new role for a conserved active site asparagine in a ubiquitin-conjugating enzyme. J Mol Graph Model 2017; 76:403-411. [DOI: 10.1016/j.jmgm.2017.07.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2017] [Revised: 07/05/2017] [Accepted: 07/06/2017] [Indexed: 11/28/2022]
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27
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Pepino AJ, Segarra-Martí J, Nenov A, Improta R, Garavelli M. Resolving Ultrafast Photoinduced Deactivations in Water-Solvated Pyrimidine Nucleosides. J Phys Chem Lett 2017; 8:1777-1783. [PMID: 28346789 DOI: 10.1021/acs.jpclett.7b00316] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
For the first time, ultrafast deactivations of photoexcited water-solvated pyrimidine nucleosides are mapped employing hybrid QM(CASPT2)/MM(AMBER) optimizations that account for explicit solvation, sugar effects, and dynamically correlated potential energy surfaces. Low-energy S1/S0 ring-puckering and ring-opening conical intersections (CIs) are suggested to drive the ballistic coherent subpicosecond (<200 fs) decays observed in each pyrimidine, the energetics controlling this processes correlating with the lifetimes observed. A second bright 1π2π* state, promoting excited-state population branching and leading toward a third CI with the ground state, is proposed to be involved in the slower ultrafast decay component observed in Thd/Cyd. The transient spectroscopic signals of the competitive deactivation channels are computed for the first time. A general unified scheme for ultrafast deactivations, spanning the sub- to few-picosecond time domain, is eventually delivered, with computed data that matches the experiments and elucidates the intrinsic photoprotection mechanism in solvated pyrimidine nucleosides.
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Affiliation(s)
- Ana Julieta Pepino
- Dipartimento di Chimica Industriale "Toso Montanari" Viale del Risorgimento, 4, 40136 Bologna, Italy
| | - Javier Segarra-Martí
- Laboratoire de Chimie UMR 5182, Université Lyon, ENS de Lyon, CNRS, Université Lyon 1 , F-69342 Lyon, France
| | - Artur Nenov
- Dipartimento di Chimica Industriale "Toso Montanari" Viale del Risorgimento, 4, 40136 Bologna, Italy
| | - Roberto Improta
- Istituto di Biostrutture e Bioimmagini CNR , Via Mezzocannone 16, I-80134 Napoli, Italy
| | - Marco Garavelli
- Dipartimento di Chimica Industriale "Toso Montanari" Viale del Risorgimento, 4, 40136 Bologna, Italy
- Laboratoire de Chimie UMR 5182, Université Lyon, ENS de Lyon, CNRS, Université Lyon 1 , F-69342 Lyon, France
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