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Li G, Meng J, Yu S, Bai X, Dai J, Song Y, Peng X, Zhao Q. Excited-State Dynamics of a CRABPII-Based Microbial Rhodopsin Mimic. J Phys Chem B 2024; 128:7712-7721. [PMID: 38940335 DOI: 10.1021/acs.jpcb.4c01296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/29/2024]
Abstract
Microbial rhodopsin, a pivotal photoreceptor protein, has garnered widespread application in diverse fields such as optogenetics, biotechnology, biodevices, etc. However, current microbial rhodopsins are all transmembrane proteins, which both complicates the investigation on the photoreaction mechanism and limits their further applications. Therefore, a specific mimic for microbial rhodopsin can not only provide a better model for understanding the mechanism but also can extend the applications. The human protein CRABPII turns out to be a good template for design mimics on rhodopsin due to the convenience in synthesis and the stability after mutations. Recently, Geiger et al. designed a new CRABPII-based mimic M1-L121E on microbial rhodopsin with the 13-cis, syn (13C) isomerization after irradiation. However, it still remains a question as to how similar it is compared with the natural microbial rhodopsin, in particular, in the aspect of the photoreaction dynamics. In this article, we investigate the excited-state dynamics of this mimic by measuring its transient absorption spectra. Our results reveal that there are two components in the solution of mimic M1-L121E at pH 8, known as protonated Schiff base (PSB) and unprotonated Schiff base (USB) states. In both states, the photoreaction process from 13-cis, syn(13C) to all-trans,anti (AT) is faster than that from the inverse direction. In addition, the photoreaction process in the PSB state is faster than that in the USB state. We compared the isomerization time of the PSB state to that of microbial rhodopsin. Our findings indicate that M1-L121E exhibits behaviors similar to those of microbial rhodopsins in the general pattern of PSB isomerization, where the isomerization from 13C to AT is much faster than its inverse direction. However, our results also reveal significant differences in the excited-state dynamics of the mimic relative to the native microbial rhodopsin, including the slower PSB isomerization rates as well as the unusual USB photoreaction dynamics at pH = 8. By elucidating the distinctive characteristics of mimics M1-L121E, this study enhances our understanding of microbial rhodopsin mimics and their potential applications.
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Affiliation(s)
- Gaoshang Li
- Center for Quantum Technology Research, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurements (MOE), School of Physics, Beijing Institute of Technology, Beijing 100081, China
| | - Jiajia Meng
- Center for Quantum Technology Research, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurements (MOE), School of Physics, Beijing Institute of Technology, Beijing 100081, China
| | - Shuang Yu
- MIIT Key Laboratory of Complex-field Intelligent Exploration, School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China
| | - Xiaolu Bai
- MIIT Key Laboratory of Complex-field Intelligent Exploration, School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China
| | - Jin Dai
- Center for Quantum Technology Research, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurements (MOE), School of Physics, Beijing Institute of Technology, Beijing 100081, China
| | - Yin Song
- MIIT Key Laboratory of Complex-field Intelligent Exploration, School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China
| | - Xubiao Peng
- Center for Quantum Technology Research, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurements (MOE), School of Physics, Beijing Institute of Technology, Beijing 100081, China
- Beijing Academy of Quantum Information Sciences, Beijing 100081, China
| | - Qing Zhao
- Center for Quantum Technology Research, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurements (MOE), School of Physics, Beijing Institute of Technology, Beijing 100081, China
- Beijing Academy of Quantum Information Sciences, Beijing 100081, China
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2
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Li G, Hu Y, Pei S, Meng J, Wang J, Wang J, Yue S, Wang Z, Wang S, Liu X, Weng Y, Peng X, Zhao Q. Excited-state dynamics of all-trans protonated retinal Schiff base in CRABPII-based rhodopsin mimics. Biophys J 2022; 121:4109-4118. [PMID: 36181266 PMCID: PMC9675042 DOI: 10.1016/j.bpj.2022.09.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 09/06/2022] [Accepted: 09/26/2022] [Indexed: 11/20/2022] Open
Abstract
The rhodopsin mimic is a chemically synthetized complex with retinyl Schiff base (RSB) formed between protein and the retinal chromophore that can mimic the natural rhodopsin-like protein. The artificial rhodopsin mimic is more stable and designable than the natural protein and hence has wider uses in photon detection devices. The mimic structure RSB, like the case in the actual rhodopsin-like protein, undergoes isomerization and protonation throughout the photoreaction process. As a result, understanding the dynamics of the RSB in the photoreaction process is critical. In this study, the ultrafast transient absorption spectra of three mutants of the cellular retinoic acid-binding protein II-based rhodopsin mimic at acidic environment were recorded, from which the related excited-state dynamics of the all-trans protonated RSB (AT-PRSB) were investigated. The transient fluorescence spectra measurements are used to validate some of the dynamic features. We find that the excited-state dynamics of AT-PRSB in three mutants share a similar pattern that differs significantly from the dynamics of 15-cis PRSB of the rhodopsin mimic in neutral solution. By comparing the dynamics across the three mutants, we discovered that the aromatic residues near the β-ionone ring structure of the retinal may help stabilize the AT-PRSB and hence slow down its isomerization rate. The experimental results provide implications on designing a rhodopsin-like protein with significant infrared fluorescence, which can be particularly useful in the applications in biosensing or bioimaging in deeper tissues.
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Affiliation(s)
- Gaoshang Li
- Center for Quantum Technology Research, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurements (MOE), School of Physics, Beijing Institute of Technology, Beijing, China
| | - Yongnan Hu
- Center for Quantum Technology Research, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurements (MOE), School of Physics, Beijing Institute of Technology, Beijing, China
| | - Sizhu Pei
- Center for Quantum Technology Research, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurements (MOE), School of Physics, Beijing Institute of Technology, Beijing, China
| | - Jiajia Meng
- Center for Quantum Technology Research, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurements (MOE), School of Physics, Beijing Institute of Technology, Beijing, China
| | - Jiayu Wang
- Beijing National Laboratory for Condensed Matter Physics, Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Ju Wang
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, Department of Physics, Peking University, Beijing, China
| | - Shuai Yue
- National Center for Nanoscience and Nanotechnology, Beijing, China
| | - Zhuan Wang
- Beijing National Laboratory for Condensed Matter Physics, Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - Shufeng Wang
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, Department of Physics, Peking University, Beijing, China
| | - Xinfeng Liu
- National Center for Nanoscience and Nanotechnology, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Yuxiang Weng
- Beijing National Laboratory for Condensed Matter Physics, Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Xubiao Peng
- Center for Quantum Technology Research, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurements (MOE), School of Physics, Beijing Institute of Technology, Beijing, China; Beijing Academy of Quantum Information Sciences, Beijing, China.
| | - Qing Zhao
- Center for Quantum Technology Research, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurements (MOE), School of Physics, Beijing Institute of Technology, Beijing, China; Beijing Academy of Quantum Information Sciences, Beijing, China.
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3
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de Grip WJ, Ganapathy S. Rhodopsins: An Excitingly Versatile Protein Species for Research, Development and Creative Engineering. Front Chem 2022; 10:879609. [PMID: 35815212 PMCID: PMC9257189 DOI: 10.3389/fchem.2022.879609] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Accepted: 05/16/2022] [Indexed: 01/17/2023] Open
Abstract
The first member and eponym of the rhodopsin family was identified in the 1930s as the visual pigment of the rod photoreceptor cell in the animal retina. It was found to be a membrane protein, owing its photosensitivity to the presence of a covalently bound chromophoric group. This group, derived from vitamin A, was appropriately dubbed retinal. In the 1970s a microbial counterpart of this species was discovered in an archaeon, being a membrane protein also harbouring retinal as a chromophore, and named bacteriorhodopsin. Since their discovery a photogenic panorama unfolded, where up to date new members and subspecies with a variety of light-driven functionality have been added to this family. The animal branch, meanwhile categorized as type-2 rhodopsins, turned out to form a large subclass in the superfamily of G protein-coupled receptors and are essential to multiple elements of light-dependent animal sensory physiology. The microbial branch, the type-1 rhodopsins, largely function as light-driven ion pumps or channels, but also contain sensory-active and enzyme-sustaining subspecies. In this review we will follow the development of this exciting membrane protein panorama in a representative number of highlights and will present a prospect of their extraordinary future potential.
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Affiliation(s)
- Willem J. de Grip
- Leiden Institute of Chemistry, Department of Biophysical Organic Chemistry, Leiden University, Leiden, Netherlands
- Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
| | - Srividya Ganapathy
- Department of Imaging Physics, Delft University of Technology, Netherlands
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4
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Santos EM, Sheng W, Esmatpour Salmani R, Tahmasebi Nick S, Ghanbarpour A, Gholami H, Vasileiou C, Geiger JH, Borhan B. Design of Large Stokes Shift Fluorescent Proteins Based on Excited State Proton Transfer of an Engineered Photobase. J Am Chem Soc 2021; 143:15091-15102. [PMID: 34516091 DOI: 10.1021/jacs.1c05039] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The incredible potential for fluorescent proteins to revolutionize biology has inspired the development of a variety of design strategies to address an equally broad range of photophysical characteristics, depending on potential applications. Of these, fluorescent proteins that simultaneously exhibit high quantum yield, red-shifted emission, and wide separation between excitation and emission wavelengths (Large Stokes Shift, LSS) are rare. The pursuit of LSS systems has led to the formation of a complex, obtained from the marriage of a rationally engineered protein (human cellular retinol binding protein II, hCRBPII) and different fluorogenic molecules, capable of supporting photobase activity. The large increase in basicity upon photoexcitation leads to protonation of the fluorophore in the excited state, dramatically red-shifting its emission, leading to an LSS protein/fluorophore complex. Essential for selective photobase activity is the intimate involvement of the target protein structure and sequence that enables Excited State Proton Transfer (ESPT). The potential power and usefulness of the strategy was demonstrated in live cell imaging of human cell lines.
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Affiliation(s)
- Elizabeth M Santos
- Michigan State University, Department of Chemistry, East Lansing, Michigan 48824, United States
| | - Wei Sheng
- Michigan State University, Department of Chemistry, East Lansing, Michigan 48824, United States
| | | | - Setare Tahmasebi Nick
- Michigan State University, Department of Chemistry, East Lansing, Michigan 48824, United States
| | - Alireza Ghanbarpour
- Michigan State University, Department of Chemistry, East Lansing, Michigan 48824, United States
| | - Hadi Gholami
- Michigan State University, Department of Chemistry, East Lansing, Michigan 48824, United States
| | - Chrysoula Vasileiou
- Michigan State University, Department of Chemistry, East Lansing, Michigan 48824, United States
| | - James H Geiger
- Michigan State University, Department of Chemistry, East Lansing, Michigan 48824, United States
| | - Babak Borhan
- Michigan State University, Department of Chemistry, East Lansing, Michigan 48824, United States
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5
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Ghanbarpour A, Santos EM, Pinger C, Assar Z, Hossaini Nasr S, Vasileiou C, Spence D, Borhan B, Geiger JH. Human Cellular Retinol Binding Protein II Forms a Domain-Swapped Trimer Representing a Novel Fold and a New Template for Protein Engineering. Chembiochem 2020; 21:3192-3196. [PMID: 32608180 PMCID: PMC8220890 DOI: 10.1002/cbic.202000405] [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: 06/24/2020] [Revised: 06/29/2020] [Indexed: 11/07/2022]
Abstract
Domain-swapping is a mechanism for evolving new protein structure from extant scaffolds, and has been an efficient protein-engineering strategy for tailoring functional diversity. However, domain swapping can only be exploited if it can be controlled, especially in cases where various folds can coexist. Herein, we describe the structure of a domain-swapped trimer of the iLBP family member hCRBPII, and suggest a mechanism for domain-swapped trimerization. It is further shown that domain-swapped trimerization can be favored by strategic installation of a disulfide bond, thus demonstrating a strategy for fold control. We further show the domain-swapped trimer to be a useful protein design template by installing a high-affinity metal binding site through the introduction of a single mutation, taking advantage of its threefold symmetry. Together, these studies show how nature can promote oligomerization, stabilize a specific oligomer, and generate new function with minimal changes to the protein sequence.
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Affiliation(s)
- Alireza Ghanbarpour
- Department of Chemistry, Michigan State University, 578 S. Shaw Lane, East Lansing, MI 48824, USA
- Yale University Medical School, Department of Cell Biology, 333 S. Cedar Street, New Haven, CT 06510, USA
| | - Elizabeth M Santos
- Department of Chemistry, Michigan State University, 578 S. Shaw Lane, East Lansing, MI 48824, USA
- Dow Performance Silicones, 2200W Salzburg Road, Midland, MI 48686, USA
| | - Cody Pinger
- Department of Biomedical Engineering, Michigan State University, 775 Woodlot Drive, East Lansing, MI 48823, USA
| | - Zahra Assar
- Cayman Chemical, 1180 East Ellsworth Road, Ann Arbor, MI 48108, USA
| | - Seyedmehdi Hossaini Nasr
- Department of Chemistry, Michigan State University, 578 S. Shaw Lane, East Lansing, MI 48824, USA
| | - Chrysoula Vasileiou
- Department of Chemistry, Michigan State University, 578 S. Shaw Lane, East Lansing, MI 48824, USA
| | - Dana Spence
- Department of Biomedical Engineering, Michigan State University, 775 Woodlot Drive, East Lansing, MI 48823, USA
| | - Babak Borhan
- Department of Chemistry, Michigan State University, 578 S. Shaw Lane, East Lansing, MI 48824, USA
| | - James H Geiger
- Department of Chemistry, Michigan State University, 578 S. Shaw Lane, East Lansing, MI 48824, USA
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6
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Gurchiek JK, Rose JB, Guberman-Pfeffer MJ, Tilluck RW, Ghosh S, Gascón JA, Beck WF. Fluorescence Anisotropy Detection of Barrier Crossing and Ultrafast Conformational Dynamics in the S 2 State of β-Carotene. J Phys Chem B 2020; 124:9029-9046. [PMID: 32955881 DOI: 10.1021/acs.jpcb.0c06961] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Carotenoids are usually only weakly fluorescent despite being very strong absorbers in the mid-visible region because their first two excited singlet states, S1 and S2, have very short lifetimes. To probe the structural mechanisms that promote the nonradiative decay of the S2 state to the S1 state, we have carried out a series of fluorescence lineshape and anisotropy measurements with a prototype carotenoid, β-carotene, in four aprotic solvents. The anisotropy values observed in the fluorescence emission bands originating from the S2 and S1 states reveal that the large internal rotations of the emission transition dipole moment, as much as 50° relative to that of the absorption transition dipole moment, are initiated during ultrafast evolution on the S2 state potential energy surface and persist upon nonradiative decay to the S1 state. Electronic structure calculations of the orientation of the transition dipole moment account for the anisotropy results in terms of torsional and pyramidal distortions near the center of the isoprenoid backbone. The excitation wavelength dependence of the fluorescence anisotropy indicates that these out-of-plane conformational motions are initiated by passage over a low-activation energy barrier from the Franck-Condon S2 structure. This conclusion is consistent with detection over the 80-200 K range of a broad, red-shifted fluorescence band from a dynamic intermediate evolving on a steep gradient of the S2 state potential energy surface after crossing the activation barrier. The temperature dependence of the oscillator strength and anisotropy indicate that nonadiabatic passage from S2 through a conical intersection seam to S1 is promoted by the out-of-plane motions of the isoprenoid backbone with strong hindrance by solvent friction.
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Affiliation(s)
- J K Gurchiek
- Department of Chemistry, Michigan State University, 578 S. Shaw Lane, East Lansing, Michigan 48824, United States
| | - Justin B Rose
- Department of Chemistry, Michigan State University, 578 S. Shaw Lane, East Lansing, Michigan 48824, United States
| | - Matthew J Guberman-Pfeffer
- Department of Chemistry, University of Connecticut, 55 North Eagleville Road, Storrs, Connecticut 06268-1712, United States
| | - Ryan W Tilluck
- Department of Chemistry, Michigan State University, 578 S. Shaw Lane, East Lansing, Michigan 48824, United States
| | - Soumen Ghosh
- Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci, 32, Milan, Lombardy 20133, Italy
| | - José A Gascón
- Department of Chemistry, University of Connecticut, 55 North Eagleville Road, Storrs, Connecticut 06268-1712, United States
| | - Warren F Beck
- Department of Chemistry, Michigan State University, 578 S. Shaw Lane, East Lansing, Michigan 48824, United States
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7
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Manathunga M, Jenkins AJ, Orozco-Gonzalez Y, Ghanbarpour A, Borhan B, Geiger JH, Larsen DS, Olivucci M. Computational and Spectroscopic Characterization of the Photocycle of an Artificial Rhodopsin. J Phys Chem Lett 2020; 11:4245-4252. [PMID: 32374610 PMCID: PMC9272672 DOI: 10.1021/acs.jpclett.0c00751] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The photocycle of a reversible photoisomerizing rhodopsin mimic (M2) is investigated. This system, based on the cellular retinoic acid binding protein, is structurally different from natural rhodopsin systems, but exhibits a similar isomerization upon light irradiation. More specifically, M2 displays a 15-cis to all-trans conversion of retinal protonated Schiff base (rPSB) and all-trans to 15-cis isomerization of unprotonated Schiff base (rUSB). Here we use hybrid quantum mechanics/molecular mechanics (QM/MM) tools coupled with transient absorption and cryokinetic UV-vis spectroscopies to investigate these isomerization processes. The results suggest that primary rPSB photoisomerization of M2 occurs around the C13═C14 double bond within 2 ps following an aborted-bicycle pedal (ABP) isomerization mechanism similar to natural microbial rhodopsins. The rUSB isomerization is much slower and occurs within 48 ps around the C15═N double bond. Our findings reveal the possibility to engineer naturally occurring mechanistic features into artificial rhodopsins and also constitute a step toward understanding the photoisomerization of UV pigments. We conclude by reinforcing the idea that the presence of the retinal chromophore inside a tight protein cavity is not mandatory to exhibit ABP mechanism.
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Affiliation(s)
- Madushanka Manathunga
- Department of Chemistry, Bowling Green State University, Bowling Green, Ohio 43403, United States
| | - Adam J Jenkins
- Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, California 95616, United States
| | - Yoelvis Orozco-Gonzalez
- Department of Chemistry, Bowling Green State University, Bowling Green, Ohio 43403, United States
| | - Alireza Ghanbarpour
- Department of Chemistry, Michigan State University, Lansing, Michigan 48824, United States
| | - Babak Borhan
- Department of Chemistry, Michigan State University, Lansing, Michigan 48824, United States
| | - James H Geiger
- Department of Chemistry, Michigan State University, Lansing, Michigan 48824, United States
| | - Delmar S Larsen
- Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, California 95616, United States
| | - Massimo Olivucci
- Department of Chemistry, Bowling Green State University, Bowling Green, Ohio 43403, United States
- Dipartimento di Biotecnologie, Chimica e Farmacia, Università di Siena, via A. Moro 2, I-53100 Siena, Italy
- Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504 Université de Strasbourg-CNRS, F-67034 Strasbourg, France
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8
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Ghanbarpour A, Pinger C, Esmatpour Salmani R, Assar Z, Santos EM, Nosrati M, Pawlowski K, Spence D, Vasileiou C, Jin X, Borhan B, Geiger JH. Engineering the hCRBPII Domain-Swapped Dimer into a New Class of Protein Switches. J Am Chem Soc 2019; 141:17125-17132. [PMID: 31557439 DOI: 10.1021/jacs.9b04664] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Protein conformational switches or allosteric proteins play a key role in the regulation of many essential biological pathways. Nonetheless, the implementation of protein conformational switches in protein design applications has proven challenging, with only a few known examples that are not derivatives of naturally occurring allosteric systems. We have discovered that the domain-swapped (DS) dimer of hCRBPII undergoes a large and robust conformational change upon retinal binding, making it a potentially powerful template for the design of protein conformational switches. Atomic resolution structures of the apo- and holo-forms illuminate a simple, mechanical movement involving sterically driven torsion angle flipping of two residues that drive the motion. We further demonstrate that the conformational "readout" can be altered by addition of cross-domain disulfide bonds, also visualized at atomic resolution. Finally, as a proof of principle, we have created an allosteric metal binding site in the DS dimer, where ligand binding results in a reversible 5-fold loss of metal binding affinity. The high resolution structure of the metal-bound variant illustrates a well-formed metal binding site at the interface of the two domains of the DS dimer and confirms the design strategy for allosteric regulation.
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Affiliation(s)
- Alireza Ghanbarpour
- Department of Chemistry , Michigan State University , East Lansing , Michigan 48824 , United States
| | - Cody Pinger
- Department of Chemistry , Michigan State University , East Lansing , Michigan 48824 , United States
| | - Rahele Esmatpour Salmani
- Department of Chemistry , Michigan State University , East Lansing , Michigan 48824 , United States
| | - Zahra Assar
- Department of Chemistry , Michigan State University , East Lansing , Michigan 48824 , United States
| | - Elizabeth M Santos
- Department of Chemistry , Michigan State University , East Lansing , Michigan 48824 , United States
| | - Meisam Nosrati
- Department of Chemistry , Michigan State University , East Lansing , Michigan 48824 , United States
| | - Kathryn Pawlowski
- Department of Chemistry , Michigan State University , East Lansing , Michigan 48824 , United States
| | - Dana Spence
- Department of Chemistry , Michigan State University , East Lansing , Michigan 48824 , United States
| | - Chrysoula Vasileiou
- Department of Chemistry , Michigan State University , East Lansing , Michigan 48824 , United States
| | - Xiangshu Jin
- Department of Chemistry , Michigan State University , East Lansing , Michigan 48824 , United States
| | - Babak Borhan
- Department of Chemistry , Michigan State University , East Lansing , Michigan 48824 , United States
| | - James H Geiger
- Department of Chemistry , Michigan State University , East Lansing , Michigan 48824 , United States
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9
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Pedraza-González L, De Vico L, del Carmen Marín M, Fanelli F, Olivucci M. a-ARM: Automatic Rhodopsin Modeling with Chromophore Cavity Generation, Ionization State Selection, and External Counterion Placement. J Chem Theory Comput 2019; 15:3134-3152. [PMID: 30916955 PMCID: PMC7141608 DOI: 10.1021/acs.jctc.9b00061] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The Automatic Rhodopsin Modeling (ARM) protocol has recently been proposed as a tool for the fast and parallel generation of basic hybrid quantum mechanics/molecular mechanics (QM/MM) models of wild type and mutant rhodopsins. However, in its present version, input preparation requires a few hours long user's manipulation of the template protein structure, which also impairs the reproducibility of the generated models. This limitation, which makes model building semiautomatic rather than fully automatic, comprises four tasks: definition of the retinal chromophore cavity, assignment of protonation states of the ionizable residues, neutralization of the protein with external counterions, and finally congruous generation of single or multiple mutations. In this work, we show that the automation of the original ARM protocol can be extended to a level suitable for performing the above tasks without user's manipulation and with an input preparation time of minutes. The new protocol, called a-ARM, delivers fully reproducible (i.e., user independent) rhodopsin QM/MM models as well as an improved model quality. More specifically, we show that the trend in vertical excitation energies observed for a set of 25 wild type and 14 mutant rhodopsins is predicted by the new protocol better than when using the original. Such an agreement is reflected by an estimated (relative to the probed set) trend deviation of 0.7 ± 0.5 kcal mol-1 (0.03 ± 0.02 eV) and mean absolute error of 1.0 kcal mol-1 (0.04 eV).
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Affiliation(s)
- Laura Pedraza-González
- Department of Biotechnologies, Chemistry and Pharmacy, Università degli Studi di Siena, via A. Moro 2, I-53100 Siena, Italy
| | - Luca De Vico
- Department of Biotechnologies, Chemistry and Pharmacy, Università degli Studi di Siena, via A. Moro 2, I-53100 Siena, Italy
| | - María del Carmen Marín
- Department of Biotechnologies, Chemistry and Pharmacy, Università degli Studi di Siena, via A. Moro 2, I-53100 Siena, Italy
| | - Francesca Fanelli
- Department of Life Sciences, Center for Neuroscience and Neurotechnology, Università degli Studi di Modena e Reggio Emilia, I-41125 Modena, Italy
| | - Massimo Olivucci
- Department of Biotechnologies, Chemistry and Pharmacy, Università degli Studi di Siena, via A. Moro 2, I-53100 Siena, Italy
- Department of Chemistry, Bowling Green State University, Bowling Green, Ohio 43403, United States
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10
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Pagano K, Paolino M, Fusi S, Zanirato V, Trapella C, Giuliani G, Cappelli A, Zanzoni S, Molinari H, Ragona L, Olivucci M. Bile Acid Binding Protein Functionalization Leads to a Fully Synthetic Rhodopsin Mimic. J Phys Chem Lett 2019; 10:2235-2243. [PMID: 30995409 DOI: 10.1021/acs.jpclett.9b00210] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Rhodopsins are photoreceptive proteins using light to drive a plethora of biological functions such as vision, proton and ion pumping, cation and anion channeling, and gene and enzyme regulation. Here we combine organic synthesis, NMR structural studies, and photochemical characterization to show that it is possible to prepare a fully synthetic mimic of rhodopsin photoreceptors. More specifically, we conjugate a bile acid binding protein with a synthetic mimic of the rhodopsin protonated Schiff base chromophore to achieve a covalent complex featuring an unnatural protein host, photoswitch, and photoswitch-protein linkage with a reverse orientation. We show that, in spite of its molecular-level diversity, light irradiation of the prepared mimic fuels a photochromic cycle driven by sequential photochemical and thermal Z/E isomerizations reminiscent of the photocycles of microbial rhodopsins.
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Affiliation(s)
- Katiuscia Pagano
- Istituto per lo Studio delle Macromolecole, CNR , Via A. Corti 12 , 20133 Milano , Italy
| | - Marco Paolino
- Dipartimento di Biotecnologie, Chimica e Farmacia (Dipartimento di Eccellenza 2018-2022) , Università degli Studi di Siena , Via Aldo Moro 2 , 53100 Siena , Italy
| | - Stefania Fusi
- Dipartimento di Biotecnologie, Chimica e Farmacia (Dipartimento di Eccellenza 2018-2022) , Università degli Studi di Siena , Via Aldo Moro 2 , 53100 Siena , Italy
| | | | | | - Germano Giuliani
- Dipartimento di Biotecnologie, Chimica e Farmacia (Dipartimento di Eccellenza 2018-2022) , Università degli Studi di Siena , Via Aldo Moro 2 , 53100 Siena , Italy
| | - Andrea Cappelli
- Dipartimento di Biotecnologie, Chimica e Farmacia (Dipartimento di Eccellenza 2018-2022) , Università degli Studi di Siena , Via Aldo Moro 2 , 53100 Siena , Italy
| | - Serena Zanzoni
- Centro Piattaforme Tecnologiche , Università di Verona , Strada Le Grazie , 37134 Verona , Italy
| | - Henriette Molinari
- Istituto per lo Studio delle Macromolecole, CNR , Via A. Corti 12 , 20133 Milano , Italy
| | - Laura Ragona
- Istituto per lo Studio delle Macromolecole, CNR , Via A. Corti 12 , 20133 Milano , Italy
| | - Massimo Olivucci
- Dipartimento di Biotecnologie, Chimica e Farmacia (Dipartimento di Eccellenza 2018-2022) , Università degli Studi di Siena , Via Aldo Moro 2 , 53100 Siena , Italy
- Chemistry Department , Bowling Green State University , Bowling Green , Ohio 43403 , United States
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