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Mao J, Jin X, Shi M, Heidenreich D, Brown LJ, Brown RCD, Lelli M, He X, Glaubitz C. Molecular mechanisms and evolutionary robustness of a color switch in proteorhodopsins. SCIENCE ADVANCES 2024; 10:eadj0384. [PMID: 38266078 PMCID: PMC10807816 DOI: 10.1126/sciadv.adj0384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 12/22/2023] [Indexed: 01/26/2024]
Abstract
Proteorhodopsins are widely distributed photoreceptors from marine bacteria. Their discovery revealed a high degree of evolutionary adaptation to ambient light, resulting in blue- and green-absorbing variants that correlate with a conserved glutamine/leucine at position 105. On the basis of an integrated approach combining sensitivity-enhanced solid-state nuclear magnetic resonance (ssNMR) spectroscopy and linear-scaling quantum mechanics/molecular mechanics (QM/MM) methods, this single residue is shown to be responsible for a variety of synergistically coupled structural and electrostatic changes along the retinal polyene chain, ionone ring, and within the binding pocket. They collectively explain the observed color shift. Furthermore, analysis of the differences in chemical shift between nuclei within the same residues in green and blue proteorhodopsins also reveals a correlation with the respective degree of conservation. Our data show that the highly conserved color change mainly affects other highly conserved residues, illustrating a high degree of robustness of the color phenotype to sequence variation.
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Affiliation(s)
- Jiafei Mao
- Institute for Biophysical Chemistry and Center for Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, Max von Laue Straße 9, 60438 Frankfurt am Main, Germany
| | - Xinsheng Jin
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, Shanghai Frontiers Science Center of Molecule Intelligent Syntheses, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200062, China
| | - Man Shi
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, Shanghai Frontiers Science Center of Molecule Intelligent Syntheses, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200062, China
| | - David Heidenreich
- Institute for Biophysical Chemistry and Center for Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, Max von Laue Straße 9, 60438 Frankfurt am Main, Germany
| | - Lynda J. Brown
- Department of Chemistry, University of Southampton, Southampton, SO17 1BJ UK
| | - Richard C. D. Brown
- Department of Chemistry, University of Southampton, Southampton, SO17 1BJ UK
| | - Moreno Lelli
- Department of Chemistry “Ugo Schiff” and Magnetic Resonance Center (CERM), University of Florence, Via della Lastruccia 3, Sesto Fiorentino, 50019 Italy
- Consorzio Interuniversitario Risonanze Magnetiche MetalloProteine (CIRMMP), Via Luigi Sacconi 6, Sesto Fiorentino, 50019 Italy
| | - Xiao He
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, Shanghai Frontiers Science Center of Molecule Intelligent Syntheses, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200062, China
- New York University–East China Normal University Center for Computational Chemistry, New York University Shanghai, Shanghai, 200062, China
| | - Clemens Glaubitz
- Institute for Biophysical Chemistry and Center for Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, Max von Laue Straße 9, 60438 Frankfurt am Main, Germany
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Kriebel CN, Asido M, Kaur J, Orth J, Braun P, Becker-Baldus J, Wachtveitl J, Glaubitz C. Structural and functional consequences of the H180A mutation of the light-driven sodium pump KR2. Biophys J 2023; 122:1003-1017. [PMID: 36528791 PMCID: PMC10111219 DOI: 10.1016/j.bpj.2022.12.023] [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: 06/26/2022] [Revised: 12/04/2022] [Accepted: 12/15/2022] [Indexed: 12/23/2022] Open
Abstract
Krokinobacter eikastus rhodopsin 2 (KR2) is a light-driven pentameric sodium pump. Its ability to translocate cations other than protons and to create an electrochemical potential makes it an attractive optogenetic tool. Tailoring its ion-pumping characteristics by mutations is therefore of great interest. In addition, understanding the functional and structural consequences of certain mutations helps to derive a functional mechanism of ion selectivity and transfer of KR2. Based on solid-state NMR spectroscopy, we report an extensive chemical shift resonance assignment of KR2 within lipid bilayers. This data set was then used to probe site-resolved allosteric effects of sodium binding, which revealed multiple responsive sites including the Schiff base nitrogen and the NDQ motif. Based on this data set, the consequences of the H180A mutation are probed. The mutant is silenced in the presence of sodium while in its absence proton pumping is observed. Our data reveal specific long-range effects along the sodium transfer pathway. These experiments are complemented by time-resolved optical spectroscopy. Our data suggest a model in which sodium uptake by the mutant can still take place, while sodium release and backflow control are disturbed.
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Affiliation(s)
- Clara Nassrin Kriebel
- Institute for Biophysical Chemistry and Center for Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Marvin Asido
- Institute for Physical and Theoretical Chemistry, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Jagdeep Kaur
- Institute for Biophysical Chemistry and Center for Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Jennifer Orth
- Institute for Biophysical Chemistry and Center for Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Philipp Braun
- Institute for Biophysical Chemistry and Center for Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Johanna Becker-Baldus
- Institute for Biophysical Chemistry and Center for Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Josef Wachtveitl
- Institute for Physical and Theoretical Chemistry, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Clemens Glaubitz
- Institute for Biophysical Chemistry and Center for Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, Frankfurt am Main, Germany.
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Chow WY, De Paëpe G, Hediger S. Biomolecular and Biological Applications of Solid-State NMR with Dynamic Nuclear Polarization Enhancement. Chem Rev 2022; 122:9795-9847. [PMID: 35446555 DOI: 10.1021/acs.chemrev.1c01043] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Solid-state NMR spectroscopy (ssNMR) with magic-angle spinning (MAS) enables the investigation of biological systems within their native context, such as lipid membranes, viral capsid assemblies, and cells. However, such ambitious investigations often suffer from low sensitivity due to the presence of significant amounts of other molecular species, which reduces the effective concentration of the biomolecule or interaction of interest. Certain investigations requiring the detection of very low concentration species remain unfeasible even with increasing experimental time for signal averaging. By applying dynamic nuclear polarization (DNP) to overcome the sensitivity challenge, the experimental time required can be reduced by orders of magnitude, broadening the feasible scope of applications for biological solid-state NMR. In this review, we outline strategies commonly adopted for biological applications of DNP, indicate ongoing challenges, and present a comprehensive overview of biological investigations where MAS-DNP has led to unique insights.
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Affiliation(s)
- Wing Ying Chow
- Univ. Grenoble Alpes, CEA, CNRS, Interdisciplinary Research Institute of Grenoble (IRIG), Modeling and Exploration of Materials Laboratory (MEM), 38054 Grenoble, France.,Univ. Grenoble Alpes, CEA, CNRS, Inst. Biol. Struct. IBS, 38044 Grenoble, France
| | - Gaël De Paëpe
- Univ. Grenoble Alpes, CEA, CNRS, Interdisciplinary Research Institute of Grenoble (IRIG), Modeling and Exploration of Materials Laboratory (MEM), 38054 Grenoble, France
| | - Sabine Hediger
- Univ. Grenoble Alpes, CEA, CNRS, Interdisciplinary Research Institute of Grenoble (IRIG), Modeling and Exploration of Materials Laboratory (MEM), 38054 Grenoble, France
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Abstract
Microbial rhodopsins represent the most abundant phototrophic systems known today. A similar molecular architecture with seven transmembrane helices and a retinal cofactor linked to a lysine in helix 7 enables a wide range of functions including ion pumping, light-controlled ion channel gating, or sensing. Deciphering their molecular mechanisms therefore requires a combined consideration of structural, functional, and spectroscopic data in order to identify key factors determining their function. Important insight can be gained by solid-state NMR spectroscopy by which the large homo-oligomeric rhodopsin complexes can be studied directly within lipid bilayers. This chapter describes the methodological background and the necessary sample preparation requirements for the study of photointermediates, for the analysis of protonation states, H-bonding and chromophore conformations, for 3D structure determination, and for probing oligomer interfaces of microbial rhodopsins. The use of data extracted from these NMR experiments is discussed in the context of complementary biophysical methods.
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Affiliation(s)
- Clara Nassrin Kriebel
- Institute of Biophysical Chemistry, Goethe University Frankfurt, Frankfurt am Main, Germany
- Centre for Biomolecular Magnetic Resonance, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Johanna Becker-Baldus
- Institute of Biophysical Chemistry, Goethe University Frankfurt, Frankfurt am Main, Germany
- Centre for Biomolecular Magnetic Resonance, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Clemens Glaubitz
- Institute of Biophysical Chemistry, Goethe University Frankfurt, Frankfurt am Main, Germany.
- Centre for Biomolecular Magnetic Resonance, Goethe University Frankfurt, Frankfurt am Main, Germany.
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Jakdetchai O, Eberhardt P, Asido M, Kaur J, Kriebel CN, Mao J, Leeder AJ, Brown LJ, Brown RCD, Becker-Baldus J, Bamann C, Wachtveitl J, Glaubitz C. Probing the photointermediates of light-driven sodium ion pump KR2 by DNP-enhanced solid-state NMR. SCIENCE ADVANCES 2021; 7:7/11/eabf4213. [PMID: 33712469 PMCID: PMC7954446 DOI: 10.1126/sciadv.abf4213] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 01/29/2021] [Indexed: 06/10/2023]
Abstract
The functional mechanism of the light-driven sodium pump Krokinobacter eikastus rhodopsin 2 (KR2) raises fundamental questions since the transfer of cations must differ from the better-known principles of rhodopsin-based proton pumps. Addressing these questions must involve a better understanding of its photointermediates. Here, dynamic nuclear polarization-enhanced solid-state nuclear magnetic resonance spectroscopy on cryo-trapped photointermediates shows that the K-state with 13-cis retinal directly interconverts into the subsequent L-state with distinct retinal carbon chemical shift differences and an increased out-of-plane twist around the C14-C15 bond. The retinal converts back into an all-trans conformation in the O-intermediate, which is the key state for sodium transport. However, retinal carbon and Schiff base nitrogen chemical shifts differ from those observed in the KR2 dark state all-trans conformation, indicating a perturbation through the nearby bound sodium ion. Our findings are supplemented by optical and infrared spectroscopy and are discussed in the context of known three-dimensional structures.
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Affiliation(s)
- Orawan Jakdetchai
- Institute for Biophysical Chemistry and Center for Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, Max von Laue Strasse 9, 60438 Frankfurt am Main, Germany
| | - Peter Eberhardt
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, Max von Laue Strasse 7, 60438 Frankfurt am Main, Germany
| | - Marvin Asido
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, Max von Laue Strasse 7, 60438 Frankfurt am Main, Germany
| | - Jagdeep Kaur
- Institute for Biophysical Chemistry and Center for Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, Max von Laue Strasse 9, 60438 Frankfurt am Main, Germany
| | - Clara Nassrin Kriebel
- Institute for Biophysical Chemistry and Center for Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, Max von Laue Strasse 9, 60438 Frankfurt am Main, Germany
| | - Jiafei Mao
- Institute for Biophysical Chemistry and Center for Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, Max von Laue Strasse 9, 60438 Frankfurt am Main, Germany
| | - Alexander J Leeder
- Department of Chemistry, University of Southampton, Southampton SO17 1BJ, Great Britain
| | - Lynda J Brown
- Department of Chemistry, University of Southampton, Southampton SO17 1BJ, Great Britain
| | - Richard C D Brown
- Department of Chemistry, University of Southampton, Southampton SO17 1BJ, Great Britain
| | - Johanna Becker-Baldus
- Institute for Biophysical Chemistry and Center for Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, Max von Laue Strasse 9, 60438 Frankfurt am Main, Germany
| | - Christian Bamann
- Max Planck Institute of Biophysics, Max von Laue Strasse 3, 60438 Frankfurt am Main, Germany
| | - Josef Wachtveitl
- Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, Max von Laue Strasse 7, 60438 Frankfurt am Main, Germany.
| | - Clemens Glaubitz
- Institute for Biophysical Chemistry and Center for Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, Max von Laue Strasse 9, 60438 Frankfurt am Main, Germany.
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Exploring Protein Structures by DNP-Enhanced Methyl Solid-State NMR Spectroscopy. J Am Chem Soc 2019; 141:19888-19901. [DOI: 10.1021/jacs.9b11195] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Munro RA, de Vlugt J, Ward ME, Kim SY, Lee KA, Jung KH, Ladizhansky V, Brown LS. Biosynthetic production of fully carbon-13 labeled retinal in E. coli for structural and functional studies of rhodopsins. JOURNAL OF BIOMOLECULAR NMR 2019; 73:49-58. [PMID: 30719609 DOI: 10.1007/s10858-019-00225-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Accepted: 01/16/2019] [Indexed: 06/09/2023]
Abstract
The isomerization of a covalently bound retinal is an integral part of both microbial and animal rhodopsin function. As such, detailed structure and conformational changes in the retinal binding pocket are of significant interest and are studied in various NMR, FTIR, and Raman spectroscopy experiments, which commonly require isotopic labeling of retinal. Unfortunately, the de novo organic synthesis of an isotopically-labeled retinal is complex and often cost-prohibitive, especially for large scale expression required for solid-state NMR. We present the novel protocol for biosynthetic production of an isotopically labeled retinal ligand concurrently with an apoprotein in E. coli as a cost-effective alternative to the de novo organic synthesis. Previously, the biosynthesis of a retinal precursor, β-carotene, has been introduced into many different organisms. We extended this system to the prototrophic E. coli expression strain BL21 in conjunction with the inducible expression of a β-dioxygenase and proteo-opsin. To demonstrate the applicability of this system, we were able to assign several new carbon resonances for proteorhodopsin-bound retinal by using fully 13C-labeled glucose as the sole carbon source. Furthermore, we demonstrated that this biosynthetically produced retinal can be extracted from E. coli cells by applying a hydrophobic solvent layer to the growth medium and reconstituted into an externally produced opsin of any desired labeling pattern.
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Affiliation(s)
- Rachel A Munro
- Departments of Physics, and Biophysics Interdepartmental Group, University of Guelph, 50 Stone Road East, Guelph, ON, N1G 2W1, Canada
| | - Jeffrey de Vlugt
- Departments of Physics, and Biophysics Interdepartmental Group, University of Guelph, 50 Stone Road East, Guelph, ON, N1G 2W1, Canada
| | - Meaghan E Ward
- Departments of Physics, and Biophysics Interdepartmental Group, University of Guelph, 50 Stone Road East, Guelph, ON, N1G 2W1, Canada
| | - So Young Kim
- Deptartment of Life Science, Institute of Biological Interfaces, Sogang University, Shinsu-Dong 1, Mapo-Gu, Seoul, 121-742, Republic of Korea
- Division of Biotechnology, College of Environmental & Bioresource Sciences, Chonbuk National University, Jeonju, Republic of Korea
| | - Keon Ah Lee
- Deptartment of Life Science, Institute of Biological Interfaces, Sogang University, Shinsu-Dong 1, Mapo-Gu, Seoul, 121-742, Republic of Korea
| | - Kwang-Hwan Jung
- Deptartment of Life Science, Institute of Biological Interfaces, Sogang University, Shinsu-Dong 1, Mapo-Gu, Seoul, 121-742, Republic of Korea
| | - Vladimir Ladizhansky
- Departments of Physics, and Biophysics Interdepartmental Group, University of Guelph, 50 Stone Road East, Guelph, ON, N1G 2W1, Canada
| | - Leonid S Brown
- Departments of Physics, and Biophysics Interdepartmental Group, University of Guelph, 50 Stone Road East, Guelph, ON, N1G 2W1, Canada.
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Mehler M, Eckert CE, Leeder AJ, Kaur J, Fischer T, Kubatova N, Brown LJ, Brown RCD, Becker-Baldus J, Wachtveitl J, Glaubitz C. Chromophore Distortions in Photointermediates of Proteorhodopsin Visualized by Dynamic Nuclear Polarization-Enhanced Solid-State NMR. J Am Chem Soc 2017; 139:16143-16153. [PMID: 29027800 DOI: 10.1021/jacs.7b05061] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Proteorhodopsin (PR) is the most abundant retinal protein on earth and functions as a light-driven proton pump. Despite extensive efforts, structural data for PR photointermediate states have not been obtained. On the basis of dynamic nuclear polarization (DNP)-enhanced solid-state NMR, we were able to analyze the retinal polyene chain between positions C10 and C15 as well as the Schiff base nitrogen in the ground state in comparison to light-induced, cryotrapped K- and M-states. A high M-state population could be achieved by preventing reprotonation of the Schiff base through a mutation of the primary proton donor (E108Q). Our data reveal unexpected large and alternating 13C chemical shift changes in the K-state propagating away from the Schiff base along the polyene chain. Furthermore, two different M-states have been observed reflecting the Schiff base reorientation after the deprotonation step. Our study provides novel insight into the photocycle of PR and also demonstrates the power of DNP-enhanced solid-state NMR to bridge the gap between functional and structural data and models.
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Affiliation(s)
- Michaela Mehler
- Institute for Biophysical Chemistry & Centre for Biomolecular Magnetic Resonance, Goethe-University Frankfurt , Frankfurt 60438, Germany
| | - Carl Elias Eckert
- Institute for Physical and Theoretical Chemistry, Goethe-University Frankfurt , Frankfurt 60438, Germany
| | - Alexander J Leeder
- Department of Chemistry, University of Southampton , Southampton SO17 1BJ, United Kingdom
| | - Jagdeep Kaur
- Institute for Biophysical Chemistry & Centre for Biomolecular Magnetic Resonance, Goethe-University Frankfurt , Frankfurt 60438, Germany
| | - Tobias Fischer
- Institute for Physical and Theoretical Chemistry, Goethe-University Frankfurt , Frankfurt 60438, Germany
| | - Nina Kubatova
- Institute for Biophysical Chemistry & Centre for Biomolecular Magnetic Resonance, Goethe-University Frankfurt , Frankfurt 60438, Germany
| | - Lynda J Brown
- Department of Chemistry, University of Southampton , Southampton SO17 1BJ, United Kingdom
| | - Richard C D Brown
- Department of Chemistry, University of Southampton , Southampton SO17 1BJ, United Kingdom
| | - Johanna Becker-Baldus
- Institute for Biophysical Chemistry & Centre for Biomolecular Magnetic Resonance, Goethe-University Frankfurt , Frankfurt 60438, Germany
| | - Josef Wachtveitl
- Institute for Physical and Theoretical Chemistry, Goethe-University Frankfurt , Frankfurt 60438, Germany
| | - Clemens Glaubitz
- Institute for Biophysical Chemistry & Centre for Biomolecular Magnetic Resonance, Goethe-University Frankfurt , Frankfurt 60438, Germany
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