1
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He Y, Collado JT, Iuliano JN, Woroniecka HA, Hall CR, Gil AA, Laptenok SP, Greetham GM, Illarionov B, Bacher A, Fischer M, French JB, Lukacs A, Meech SR, Tonge PJ. Elucidating the Signal Transduction Mechanism of the Blue-Light-Regulated Photoreceptor YtvA: From Photoactivation to Downstream Regulation. ACS Chem Biol 2024; 19:696-706. [PMID: 38385342 PMCID: PMC10949197 DOI: 10.1021/acschembio.3c00722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 01/25/2024] [Accepted: 02/12/2024] [Indexed: 02/23/2024]
Abstract
The blue-light photoreceptor YtvA from Bacillus subtilis has an N-terminal flavin mononucleotide (FMN)-binding light-oxygen-voltage (LOV) domain that is fused to a C-terminal sulfate transporter and anti-σ factor antagonist (STAS) output domain. To interrogate the signal transduction pathway that leads to photoactivation, the STAS domain was replaced with a histidine kinase, so that photoexcitation of the flavin could be directly correlated with biological activity. N94, a conserved Asn that is hydrogen bonded to the FMN C2═O group, was replaced with Ala, Asp, and Ser residues to explore the role of this residue in triggering the structural dynamics that activate the output domain. Femtosecond to millisecond time-resolved multiple probe spectroscopy coupled with a fluorescence polarization assay revealed that the loss of the hydrogen bond between N94 and the C2═O group decoupled changes in the protein structure from photoexcitation. In addition, alterations in N94 also decreased the stability of the Cys-FMN adduct formed in the light-activated state by up to a factor of ∼25. Collectively, these studies shed light on the role of the hydrogen bonding network in the LOV β-scaffold in signal transduction.
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Affiliation(s)
- YongLe He
- Department
of Chemistry, Stony Brook University, Stony Brook, New York 11794, United States
| | | | - James N. Iuliano
- Department
of Chemistry, Stony Brook University, Stony Brook, New York 11794, United States
| | - Helena A. Woroniecka
- Department
of Chemistry, Stony Brook University, Stony Brook, New York 11794, United States
| | - Christopher R. Hall
- Central
Laser Facility, Research Complex at Harwell, Rutherford Appleton Laboratory, Didcot OX11 0QX, U.K.
| | - Agnieszka A. Gil
- Department
of Chemistry, Stony Brook University, Stony Brook, New York 11794, United States
| | | | - Gregory M. Greetham
- Central
Laser Facility, Research Complex at Harwell, Rutherford Appleton Laboratory, Didcot OX11 0QX, U.K.
| | - Boris Illarionov
- Institut
für Biochemie und Lebensmittelchemie, Universität Hamburg, Grindelallee 117, D-20146 Hamburg, Germany
| | - Adelbert Bacher
- Institut
für Biochemie und Lebensmittelchemie, Universität Hamburg, Grindelallee 117, D-20146 Hamburg, Germany
- TUM School
of Natural Sciences, Technical University
of Munich, 85747 Garching, Germany
| | - Markus Fischer
- Institut
für Biochemie und Lebensmittelchemie, Universität Hamburg, Grindelallee 117, D-20146 Hamburg, Germany
| | - Jarrod B. French
- Department
of Chemistry, Stony Brook University, Stony Brook, New York 11794, United States
- The
Hormel Institute, University of Minnesota, Austin, Minnesota 55912, United States
| | - Andras Lukacs
- School
of Chemistry, University of East Anglia, Norwich NR4 7TJ, U.K.
- Department
of Biophysics, Medical School, University
of Pecs, Szigeti ut 12, 7624 Pecs, Hungary
| | - Stephen R. Meech
- School
of Chemistry, University of East Anglia, Norwich NR4 7TJ, U.K.
| | - Peter J. Tonge
- Department
of Chemistry, Stony Brook University, Stony Brook, New York 11794, United States
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2
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Tolentino Collado J, Bodis E, Pasitka J, Szucs M, Fekete Z, Kis-Bicskei N, Telek E, Pozsonyi K, Kapetanaki SM, Greetham G, Tonge PJ, Meech SR, Lukacs A. Single Amino Acid Mutation Decouples Photochemistry of the BLUF Domain from the Enzymatic Function of OaPAC and Drives the Enzyme to a Switched-on State. J Mol Biol 2024; 436:168312. [PMID: 37827329 PMCID: PMC11256462 DOI: 10.1016/j.jmb.2023.168312] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 09/29/2023] [Accepted: 10/05/2023] [Indexed: 10/14/2023]
Abstract
Photoactivated adenylate cyclases (PACs) are light-activated enzymes that combine a BLUF (blue-light using flavin) domain and an adenylate cyclase domain that are able to increase the levels of the important second messenger cAMP (cyclic adenosine monophosphate) upon blue-light excitation. The light-induced changes in the BLUF domain are transduced to the adenylate cyclase domain via a mechanism that has not yet been established. One critical residue in the photoactivation mechanism of BLUF domains, present in the vicinity of the flavin is the glutamine amino acid close to the N5 of the flavin. The role of this residue has been investigated extensively both experimentally and theoretically. However, its role in the activity of the photoactivated adenylate cyclase, OaPAC has never been addressed. In this work, we applied ultrafast transient visible and infrared spectroscopies to study the photochemistry of the Q48E OaPAC mutant. This mutation altered the primary electron transfer process and switched the enzyme into a permanent 'on' state, able to increase the cAMP levels under dark conditions compared to the cAMP levels of the dark-adapted state of the wild-type OaPAC. Differential scanning calorimetry measurements point to a less compact structure for the Q48E OaPAC mutant. The ensemble of these findings provide insight into the important elements in PACs and how their fine tuning may help in the design of optogenetic devices.
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Affiliation(s)
| | - Emoke Bodis
- Department of Biophysics, Medical School, University of Pecs, Szigeti str. 12, 7624 Pecs, Hungary
| | - Jonatan Pasitka
- Department of Biophysics, Medical School, University of Pecs, Szigeti str. 12, 7624 Pecs, Hungary
| | - Mihaly Szucs
- Department of Biophysics, Medical School, University of Pecs, Szigeti str. 12, 7624 Pecs, Hungary
| | - Zsuzsanna Fekete
- Department of Biophysics, Medical School, University of Pecs, Szigeti str. 12, 7624 Pecs, Hungary
| | - Nikolett Kis-Bicskei
- Department of Biophysics, Medical School, University of Pecs, Szigeti str. 12, 7624 Pecs, Hungary
| | - Elek Telek
- Department of Biophysics, Medical School, University of Pecs, Szigeti str. 12, 7624 Pecs, Hungary
| | - Kinga Pozsonyi
- Department of Biophysics, Medical School, University of Pecs, Szigeti str. 12, 7624 Pecs, Hungary
| | - Sofia M Kapetanaki
- Department of Biophysics, Medical School, University of Pecs, Szigeti str. 12, 7624 Pecs, Hungary
| | - Greg Greetham
- Central Laser Facility, Research Complex at Harwell, Rutherford Appleton Laboratory, Didcot OX11 0QX, UK
| | - Peter J Tonge
- Department of Chemistry, Stony Brook University, New York 11794, United States.
| | - Stephen R Meech
- School of Chemistry, University of East Anglia, Norwich, NR4 7TJ, UK.
| | - Andras Lukacs
- Department of Biophysics, Medical School, University of Pecs, Szigeti str. 12, 7624 Pecs, Hungary.
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3
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Tolentino Collado J, Iuliano JN, Pirisi K, Jewlikar S, Adamczyk K, Greetham GM, Towrie M, Tame JRH, Meech SR, Tonge PJ, Lukacs A. Unraveling the Photoactivation Mechanism of a Light-Activated Adenylyl Cyclase Using Ultrafast Spectroscopy Coupled with Unnatural Amino Acid Mutagenesis. ACS Chem Biol 2022; 17:2643-2654. [PMID: 36038143 PMCID: PMC9486806 DOI: 10.1021/acschembio.2c00575] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The hydrogen bonding network that surrounds the flavin in blue light using flavin adenine dinucleotide (BLUF) photoreceptors plays a crucial role in sensing and communicating the changes in the electronic structure of the flavin to the protein matrix upon light absorption. Using time-resolved infrared spectroscopy (TRIR) and unnatural amino acid incorporation, we investigated the photoactivation mechanism and the role of the conserved tyrosine (Y6) in the forward reaction of the photoactivated adenylyl cyclase from Oscillatoria acuminata (OaPAC). Our work elucidates the direct connection between BLUF photoactivation and the structural and functional implications on the partner protein for the first time. The TRIR results demonstrate the formation of the neutral flavin radical as an intermediate species on the photoactivation pathway which decays to form the signaling state. Using fluorotyrosine analogues to modulate the physical properties of Y6, the TRIR data reveal that a change in the pKa and/or reduction potential of Y6 has a profound effect on the forward reaction, consistent with a mechanism involving proton transfer or proton-coupled electron transfer from Y6 to the electronically excited FAD. Decreasing the pKa from 9.9 to <7.2 and/or increasing the reduction potential by 200 mV of Y6 prevents proton transfer to the flavin and halts the photocycle at FAD•-. The lack of protonation of the anionic flavin radical can be directly linked to photoactivation of the adenylyl cyclase (AC) domain. While the 3F-Y6 and 2,3-F2Y6 variants undergo the complete photocycle and catalyze the conversion of ATP into cAMP, enzyme activity is abolished in the 3,5-F2Y6 and 2,3,5-F3Y6 variants where the photocycle is halted at FAD•-. Our results thus show that proton transfer plays an essential role in initiating the structural reorganization of the AC domain that results in AC activity.
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Affiliation(s)
| | - James N. Iuliano
- Department
of Chemistry, Stony Brook University, New York, New York 11794, United States
| | - Katalin Pirisi
- Department
of Biophysics, Medical School, University
of Pecs, Szigeti Street 12, Pecs 7624, Hungary
| | - Samruddhi Jewlikar
- Department
of Chemistry, Stony Brook University, New York, New York 11794, United States
| | - Katrin Adamczyk
- School
of Chemistry, University of East Anglia, Norwich NR4 7TJ, U.K.
| | - Gregory M. Greetham
- Central
Laser Facility, Research Complex at Harwell, Rutherford Appleton Laboratory, Didcot OX11 0QX, U.K.
| | - Michael Towrie
- Central
Laser Facility, Research Complex at Harwell, Rutherford Appleton Laboratory, Didcot OX11 0QX, U.K.
| | - Jeremy R. H. Tame
- Drug
Design Laboratory, Graduate School of Medical Life Science, Yokohama City University, Tsurumi, Yokohama 230-0045, Japan
| | - Stephen R. Meech
- School
of Chemistry, University of East Anglia, Norwich NR4 7TJ, U.K.,
| | - Peter J. Tonge
- Department
of Chemistry, Stony Brook University, New York, New York 11794, United States,
| | - Andras Lukacs
- Department
of Biophysics, Medical School, University
of Pecs, Szigeti Street 12, Pecs 7624, Hungary,
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4
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Nakasone Y, Terazima M. Time-resolved diffusion reveals photoreactions of BLUF proteins with similar functional domains. Photochem Photobiol Sci 2022; 21:493-507. [PMID: 35391638 DOI: 10.1007/s43630-022-00214-2] [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: 02/04/2022] [Accepted: 03/21/2022] [Indexed: 11/30/2022]
Abstract
BLUF (blue light sensor using flavin) proteins are the blue light receptors that consist of flavin-binding BLUF domains and functional domains. Upon blue light excitation, the hydrogen bond network around the flavin chromophore changes, and the absorption spectrum in the visible region shifts to red. Light signal received in the BLUF domain is intramolecularly or intermolecularly transmitted to the functional region. In this review, the reactions of three BLUF proteins with similar EAL functional groups within the protein (BlrP1, and YcgF), or with a separated target protein (PapB) are described using time-resolved diffusion technique. The diffusion coefficients (D) of the BLUF domains did not significantly change upon photoexcitation, whereas those of the full-length proteins BlrP1 and YcgF and the PapB-PapA system significantly decreased. The changes in D should be due to diffusion-sensitive conformational changes (DSCC) that alter the friction of diffusion. The time constants of the major D changes of BlrP1 and PapB-PapA were similar (~ 20 ms), although the magnitude of the friction change depended on the proteins. Similarities and differences among the reactions of these proteins were clarified from the viewpoint of DSCC.
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Affiliation(s)
- Yusuke Nakasone
- Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan
| | - Masahide Terazima
- Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan.
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5
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Abstract
Light activated proteins are at the heart of photobiology and optogenetics, so there is wide interest in understanding the mechanisms coupling optical excitation to protein function. In addition, such light activated proteins provide unique insights into the real-time dynamics of protein function. Using pump-probe spectroscopy, the function of a photoactive protein can be initiated by a sub-100 fs pulse of light, allowing subsequent protein dynamics to be probed from femtoseconds to milliseconds and beyond. Among the most interesting photoactive proteins are the blue light using flavin (BLUF) domain proteins, which regulate the response to light of a wide range of bacterial and some euglenoid processes. The photosensing mechanism of BLUF domains has long been a subject of debate. In contrast to other photoactive proteins, the electronic and nuclear structure of the chromophore (flavin) is the same in dark- and light-adapted states. Thus, the driving force for photoactivity is unclear.To address this question requires real-time observation of both chromophore excited state processes and their effect on the structure and dynamics of the surrounding protein matrix. In this Account we describe how time-resolved infrared (IR) experiments, coupled with chemical biology, provide important new insights into the signaling mechanism of BLUF domains. IR measurements are sensitive to changes in both chromophore electronic structure and protein hydrogen bonding interactions. These contributions are resolved by isotope labeling of the chromophore and protein separately. Further, a degree of control over BLUF photochemistry is achieved through mutagenesis, while unnatural amino acid substitution allows us to both fine-tune the photochemistry and time resolve protein dynamics with spatial resolution.Ultrafast studies of BLUF domains reveal non-single-exponential relaxation of the flavin excited state. That relaxation leads within one nanosecond to the original flavin ground state bound in a modified hydrogen-bonding network, as seen in transient and steady-state IR spectroscopy. The change in H-bond configuration arises from formation of an unusual enol (imine) form of a critical glutamine residue. The dynamics observed, complemented by quantum mechanical calculations, suggest a unique sequential electron then double proton transfer reaction as the driving force, followed by rapid reorganization in the binding site and charge recombination. Importantly, studies of several BLUF domains reveal an unexpected diversity in their dynamics, although the underlying structure appears highly conserved. It is suggested that this diversity reflects structural dynamics in the ground state at standard temperature, leading to a distribution of structures and photochemical outcomes. Time resolved IR measurements were extended to the millisecond regime for one BLUF domain, revealing signaling state formation on the microsecond time scale. The mechanism involves reorganization of a β-sheet connected to the chromophore binding pocket via a tryptophan residue. The potential of site-specific labeling amino acids with IR labels as a tool for probing protein structural dynamics was demonstrated.In summary, time-resolved IR studies of BLUF domains (along with related studies at visible wavelengths and quantum and molecular dynamics calculations) have resolved the photoactivation mechanism and real-time dynamics of signaling state formation. These measurements provide new insights into protein structural dynamics and will be important in optimizing the potential of BLUF domains in optobiology.
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Affiliation(s)
- Andras Lukacs
- Department of Biophysics, Medical School, University of Pécs, Szigeti str 12, 7624 Pécs, Hungary
| | - Peter J. Tonge
- Department of Chemistry, Stony Brook University, 100 Nicolls Road, Stony Brook, New York 11794-3400, United States
| | - Stephen R. Meech
- School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, U.K
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6
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Hashem S, Macaluso V, Nottoli M, Lipparini F, Cupellini L, Mennucci B. From crystallographic data to the solution structure of photoreceptors: the case of the AppA BLUF domain. Chem Sci 2021; 12:13331-13342. [PMID: 34777752 PMCID: PMC8528011 DOI: 10.1039/d1sc03000k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 09/01/2021] [Indexed: 12/28/2022] Open
Abstract
Photoreceptor proteins bind a chromophore, which, upon light absorption, modifies its geometry or its interactions with the protein, finally inducing the structural change needed to switch the protein from an inactive to an active or signaling state. In the Blue Light-Using Flavin (BLUF) family of photoreceptors, the chromophore is a flavin and the changes have been connected with a rearrangement of the hydrogen bond network around it on the basis of spectroscopic changes measured for the dark-to-light conversion. However, the exact conformational change triggered by the photoexcitation is still elusive mainly because a clear consensus on the identity not only of the light activated state but also of the dark one has not been achieved. Here, we present an integrated investigation that combines microsecond MD simulations starting from the two conflicting crystal structures available for the AppA BLUF domain with calculations of NMR, IR and UV-Vis spectra using a polarizable QM/MM approach. Thanks to such a combined analysis of the three different spectroscopic responses, a robust characterization of the structure of the dark state in solution is given together with the uncovering of important flaws of the most popular molecular mechanisms present in the literature for the dark-to-light activation.
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Affiliation(s)
- Shaima Hashem
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa Via G. Moruzzi 13 56124 Pisa Italy
| | - Veronica Macaluso
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa Via G. Moruzzi 13 56124 Pisa Italy
| | - Michele Nottoli
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa Via G. Moruzzi 13 56124 Pisa Italy
| | - Filippo Lipparini
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa Via G. Moruzzi 13 56124 Pisa Italy
| | - Lorenzo Cupellini
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa Via G. Moruzzi 13 56124 Pisa Italy
| | - Benedetta Mennucci
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa Via G. Moruzzi 13 56124 Pisa Italy
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7
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Macaluso V, Hashem S, Nottoli M, Lipparini F, Cupellini L, Mennucci B. Ultrafast Transient Infrared Spectroscopy of Photoreceptors with Polarizable QM/MM Dynamics. J Phys Chem B 2021; 125:10282-10292. [PMID: 34476939 PMCID: PMC8450903 DOI: 10.1021/acs.jpcb.1c05753] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 08/04/2021] [Indexed: 01/02/2023]
Abstract
Ultrafast transient infrared (TRIR) spectroscopy is widely used to measure the excitation-induced structural changes of protein-bound chromophores. Here, we design a novel and general strategy to compute TRIR spectra of photoreceptors by combining μs-long MM molecular dynamics with ps-long QM/AMOEBA Born-Oppenheimer molecular dynamics (BOMD) trajectories for both ground and excited electronic states. As a proof of concept, the strategy is here applied to AppA, a blue-light-utilizing flavin (BLUF) protein, found in bacteria. We first analyzed the short-time evolution of the embedded flavin upon excitation revealing that its dynamic Stokes shift is ultrafast and mainly driven by the internal reorganization of the chromophore. A different normal-mode representation was needed to describe ground- and excited-state IR spectra. In this way, we could assign all of the bands observed in the measured transient spectrum. In particular, we could characterize the flavin isoalloxazine-ring region of the spectrum, for which a full and clear description was missing.
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Affiliation(s)
| | | | - Michele Nottoli
- Dipartimento di Chimica e
Chimica Industriale, University of Pisa, via G. Moruzzi 13, 56124 Pisa, Italy
| | - Filippo Lipparini
- Dipartimento di Chimica e
Chimica Industriale, University of Pisa, via G. Moruzzi 13, 56124 Pisa, Italy
| | - Lorenzo Cupellini
- Dipartimento di Chimica e
Chimica Industriale, University of Pisa, via G. Moruzzi 13, 56124 Pisa, Italy
| | - Benedetta Mennucci
- Dipartimento di Chimica e
Chimica Industriale, University of Pisa, via G. Moruzzi 13, 56124 Pisa, Italy
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8
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Pirisi K, Nag L, Fekete Z, Iuliano JN, Tolentino Collado J, Clark IP, Pécsi I, Sournia P, Liebl U, Greetham GM, Tonge PJ, Meech SR, Vos MH, Lukacs A. Identification of the vibrational marker of tyrosine cation radical using ultrafast transient infrared spectroscopy of flavoprotein systems. Photochem Photobiol Sci 2021; 20:369-378. [PMID: 33721272 DOI: 10.1007/s43630-021-00024-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 02/09/2021] [Indexed: 11/29/2022]
Abstract
Tryptophan and tyrosine radical intermediates play crucial roles in many biological charge transfer processes. Particularly in flavoprotein photochemistry, short-lived reaction intermediates can be studied by the complementary techniques of ultrafast visible and infrared spectroscopy. The spectral properties of tryptophan radical are well established, and the formation of neutral tyrosine radicals has been observed in many biological processes. However, only recently, the formation of a cation tyrosine radical was observed by transient visible spectroscopy in a few systems. Here, we assigned the infrared vibrational markers of the cationic and neutral tyrosine radical at 1483 and 1502 cm-1 (in deuterated buffer), respectively, in a variant of the bacterial methyl transferase TrmFO, and in the native glucose oxidase. In addition, we studied a mutant of AppABLUF blue-light sensor domain from Rhodobacter sphaeroides in which only a direct formation of the neutral radical was observed. Our studies highlight the exquisite sensitivity of transient infrared spectroscopy to low concentrations of specific radicals.
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Affiliation(s)
- Katalin Pirisi
- Department of Biophysics, Medical School, University of Pecs, Szigeti Str. 12, 7624, Pecs, Hungary
| | - Lipsa Nag
- Laboratoire d'Optique et Biosciences, CNRS, INSERM, Ecole Polytechnique, Institut Polytechnique de Paris, 91128, Palaiseau, France
| | - Zsuzsanna Fekete
- Department of Biophysics, Medical School, University of Pecs, Szigeti Str. 12, 7624, Pecs, Hungary
| | - James N Iuliano
- Department of Chemistry, Stony Brook University, Stony Brook, NY, 11794-3400, USA
| | | | - Ian P Clark
- Central Laser Facility, Research Complex at Harwell, Harwell Science and Innovation Campus, Didcot, OX11 0QX, Oxon, UK
| | - Ildikó Pécsi
- Department of Biophysics, Medical School, University of Pecs, Szigeti Str. 12, 7624, Pecs, Hungary
| | - Pierre Sournia
- Laboratoire d'Optique et Biosciences, CNRS, INSERM, Ecole Polytechnique, Institut Polytechnique de Paris, 91128, Palaiseau, France
| | - Ursula Liebl
- Laboratoire d'Optique et Biosciences, CNRS, INSERM, Ecole Polytechnique, Institut Polytechnique de Paris, 91128, Palaiseau, France
| | - Gregory M Greetham
- Central Laser Facility, Research Complex at Harwell, Harwell Science and Innovation Campus, Didcot, OX11 0QX, Oxon, UK
| | - Peter J Tonge
- Department of Chemistry, Stony Brook University, Stony Brook, NY, 11794-3400, USA
| | - Stephen R Meech
- School of Chemistry, University of East Anglia, Norwich, NR4 7TJ, UK
| | - Marten H Vos
- Laboratoire d'Optique et Biosciences, CNRS, INSERM, Ecole Polytechnique, Institut Polytechnique de Paris, 91128, Palaiseau, France.
| | - Andras Lukacs
- Department of Biophysics, Medical School, University of Pecs, Szigeti Str. 12, 7624, Pecs, Hungary.
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9
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Iuliano JN, Hall CR, Green D, Jones GA, Lukacs A, Illarionov B, Bacher A, Fischer M, French JB, Tonge PJ, Meech SR. Excited State Vibrations of Isotopically Labeled FMN Free and Bound to a Light-Oxygen-Voltage (LOV) Protein. J Phys Chem B 2020; 124:7152-7165. [PMID: 32786715 PMCID: PMC7533957 DOI: 10.1021/acs.jpcb.0c04943] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Flavoproteins are important blue light sensors in photobiology and play a key role in optogenetics. The characterization of their excited state structure and dynamics is thus an important objective. Here, we present a detailed study of excited state vibrational spectra of flavin mononucleotide (FMN), in solution and bound to the LOV-2 (Light-Oxygen-Voltage) domain of Avena sativa phototropin. Vibrational frequencies are determined for the optically excited singlet state and the reactive triplet state, through resonant ultrafast femtosecond stimulated Raman spectroscopy (FSRS). To assign the observed spectra, vibrational frequencies of the excited states are calculated using density functional theory, and both measurement and theory are applied to four different isotopologues of FMN. Excited state mode assignments are refined in both states, and their sensitivity to deuteration and protein environment are investigated. We show that resonant FSRS provides a useful tool for characterizing photoactive flavoproteins and is able to highlight chromophore localized modes and to record hydrogen/deuterium exchange.
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Affiliation(s)
- James N. Iuliano
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | | | - Dale Green
- School of Chemistry, University of East Anglia, Norwich NR4 7TJ, U.K
| | - Garth A. Jones
- School of Chemistry, University of East Anglia, Norwich NR4 7TJ, U.K
| | - Andras Lukacs
- Department of Biophysics, Medical School, University of Pecs, Szigeti ut 12, 7624 Pecs, Hungary
| | - Boris Illarionov
- Institut für Biochemie und Lebensmittelchemie, Universität Hamburg, Grindelallee 117, D-20146 Hamburg, Germany
| | - Adelbert Bacher
- Institut für Biochemie und Lebensmittelchemie, Universität Hamburg, Grindelallee 117, D-20146 Hamburg, Germany
- Department of Chemistry, Technical University of Munich, 85747 Garching, Germany
| | - Markus Fischer
- Institut für Biochemie und Lebensmittelchemie, Universität Hamburg, Grindelallee 117, D-20146 Hamburg, Germany
| | - Jarrod B. French
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | - Peter J. Tonge
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | - Stephen R. Meech
- School of Chemistry, University of East Anglia, Norwich NR4 7TJ, U.K
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10
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Hardman SJO, Iorgu AI, Heyes DJ, Scrutton NS, Sazanovich IV, Hay S. Ultrafast Vibrational Energy Transfer between Protein and Cofactor in a Flavoenzyme. J Phys Chem B 2020; 124:5163-5168. [PMID: 32496802 PMCID: PMC7467709 DOI: 10.1021/acs.jpcb.0c04929] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Indexed: 01/19/2023]
Abstract
Protein motions and enzyme catalysis are often linked. It is hypothesized that ultrafast vibrations (femtosecond-picosecond) enhance the rate of hydride transfer catalyzed by members of the old yellow enzyme (OYE) family of ene-reductases. Here, we use time-resolved infrared (TRIR) spectroscopy in combination with stable "heavy" isotopic labeling (2H, 13C, 15N) of protein and/or cofactor to probe the vibrational energy transfer (VET) between pentaerythritol tetranitrate reductase (a member of the OYE family) and its noncovalently bound flavin mononucleotide (FMN) cofactor. We show that when the FMN cofactor is photoexcited with visible light, vibrational energy is transferred from the flavin to the surrounding protein environment on the picosecond timescale. This finding expands the scope of VET investigation in proteins, which are limited by suitable intrinsic probes, and may have implications in the understanding of the mechanism of recently discovered photoactive flavoenzymes.
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Affiliation(s)
- Samantha J. O. Hardman
- Manchester Institute
of Biotechnology and Department of Chemistry, Faculty of Science and
Engineering, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Andreea I. Iorgu
- Manchester Institute
of Biotechnology and Department of Chemistry, Faculty of Science and
Engineering, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Derren J. Heyes
- Manchester Institute
of Biotechnology and Department of Chemistry, Faculty of Science and
Engineering, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Nigel S. Scrutton
- Manchester Institute
of Biotechnology and Department of Chemistry, Faculty of Science and
Engineering, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Igor V. Sazanovich
- Central Laser Facility, Research Complex
at Harwell, Science and Technology Facilities
Council, Harwell Oxford, Didcot OX11 0QX, United Kingdom
| | - Sam Hay
- Manchester Institute
of Biotechnology and Department of Chemistry, Faculty of Science and
Engineering, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
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11
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Karadi K, Kapetanaki SM, Raics K, Pecsi I, Kapronczai R, Fekete Z, Iuliano JN, Collado JT, Gil AA, Orban J, Nyitrai M, Greetham GM, Vos MH, Tonge PJ, Meech SR, Lukacs A. Functional dynamics of a single tryptophan residue in a BLUF protein revealed by fluorescence spectroscopy. Sci Rep 2020; 10:2061. [PMID: 32029866 PMCID: PMC7005313 DOI: 10.1038/s41598-020-59073-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 01/23/2020] [Indexed: 11/17/2022] Open
Abstract
Blue Light Using Flavin (BLUF) domains are increasingly being adopted for use in optogenetic constructs. Despite this, much remains to be resolved on the mechanism of their activation. The advent of unnatural amino acid mutagenesis opens up a new toolbox for the study of protein structural dynamics. The tryptophan analogue, 7-aza-Trp (7AW) was incorporated in the BLUF domain of the Activation of Photopigment and pucA (AppA) photoreceptor in order to investigate the functional dynamics of the crucial W104 residue during photoactivation of the protein. The 7-aza modification to Trp makes selective excitation possible using 310 nm excitation and 380 nm emission, separating the signals of interest from other Trp and Tyr residues. We used Förster energy transfer (FRET) between 7AW and the flavin to estimate the distance between Trp and flavin in both the light- and dark-adapted states in solution. Nanosecond fluorescence anisotropy decay and picosecond fluorescence lifetime measurements for the flavin revealed a rather dynamic picture for the tryptophan residue. In the dark-adapted state, the major population of W104 is pointing away from the flavin and can move freely, in contrast to previous results reported in the literature. Upon blue-light excitation, the dominant tryptophan population is reorganized, moves closer to the flavin occupying a rigidly bound state participating in the hydrogen-bond network around the flavin molecule.
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Affiliation(s)
- Kristof Karadi
- Department of Biophysics, Medical School, University of Pécs, 7624, Pécs, Hungary.,Szentagothai Research Center, University of Pécs, 7624, Pécs, Hungary
| | - Sofia M Kapetanaki
- Department of Biophysics, Medical School, University of Pécs, 7624, Pécs, Hungary.,Szentagothai Research Center, University of Pécs, 7624, Pécs, Hungary
| | - Katalin Raics
- Department of Biophysics, Medical School, University of Pécs, 7624, Pécs, Hungary
| | - Ildiko Pecsi
- Department of Biophysics, Medical School, University of Pécs, 7624, Pécs, Hungary
| | - Robert Kapronczai
- Department of Biophysics, Medical School, University of Pécs, 7624, Pécs, Hungary
| | - Zsuzsanna Fekete
- Department of Biophysics, Medical School, University of Pécs, 7624, Pécs, Hungary
| | - James N Iuliano
- Department of Chemistry, Stony Brook University, Stony Brook, NY, 11794-3400, USA
| | | | - Agnieszka A Gil
- Department of Chemistry, Stony Brook University, Stony Brook, NY, 11794-3400, USA
| | - Jozsef Orban
- Department of Biophysics, Medical School, University of Pécs, 7624, Pécs, Hungary
| | - Miklos Nyitrai
- Department of Biophysics, Medical School, University of Pécs, 7624, Pécs, Hungary.,Szentagothai Research Center, University of Pécs, 7624, Pécs, Hungary
| | - Greg M Greetham
- Central Laser Facility, Harwell Science and Innovation Campus, Didcot, Oxfordshire, UK
| | - Marten H Vos
- LOB, CNRS, INSERM, Ecole Polytechnique, Institut Polytechnique de Paris, 91128, Palaiseau, Cedex, France
| | - Peter J Tonge
- Department of Chemistry, Stony Brook University, Stony Brook, NY, 11794-3400, USA
| | - Stephen R Meech
- School of Chemistry, University of East Anglia, Norwich, NR4 7TJ, UK
| | - Andras Lukacs
- Department of Biophysics, Medical School, University of Pécs, 7624, Pécs, Hungary. .,Szentagothai Research Center, University of Pécs, 7624, Pécs, Hungary.
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12
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Fujisawa T, Masuda S. Light-induced chromophore and protein responses and mechanical signal transduction of BLUF proteins. Biophys Rev 2017; 10:327-337. [PMID: 29235080 PMCID: PMC5899715 DOI: 10.1007/s12551-017-0355-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 11/15/2017] [Indexed: 11/26/2022] Open
Abstract
Photoreceptor proteins have been used to study how protein conformational changes are induced by alterations in their environments and how their signals are transmitted to downstream factors to dictate physiological responses. These proteins are attractive models because their signal transduction aspects and structural changes can be precisely regulated in vivo and in vitro based on light intensity. Among the known photoreceptors, members of the blue light–using flavin (BLUF) protein family have been well characterized with regard to how they control various light-dependent physiological responses in several microorganisms. Herein, we summarize our current understanding of their photoactivation and signal-transduction mechanisms. For signal transduction, we review recent studies concerning how the BLUF protein, PixD, transmits a light-induced signal to its downstream factor, PixE, to modulate phototaxis of the cyanobacterium Synechocystis sp. PCC6803.
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Affiliation(s)
- Tomotsumi Fujisawa
- Department of Chemistry, Graduate School of Science and Engineering, Saga University, Saga, 840-8502 Japan
| | - Shinji Masuda
- Center for Biological Resources & Informatics, Tokyo Institute of Technology, Yokohama, 226-8501 Japan
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13
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Hall CR, Heisler IA, Jones GA, Frost JE, Gil AA, Tonge PJ, Meech SR. Femtosecond stimulated Raman study of the photoactive flavoprotein AppABLUF. Chem Phys Lett 2017. [DOI: 10.1016/j.cplett.2017.03.030] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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14
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Gil AA, Laptenok SP, French JB, Iuliano JN, Lukacs A, Hall CR, Sazanovich IV, Greetham GM, Bacher A, Illarionov B, Fischer M, Tonge PJ, Meech SR. Femtosecond to Millisecond Dynamics of Light Induced Allostery in the Avena sativa LOV Domain. J Phys Chem B 2017; 121:1010-1019. [PMID: 28068090 DOI: 10.1021/acs.jpcb.7b00088] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The rational engineering of photosensor proteins underpins the field of optogenetics, in which light is used for spatiotemporal control of cell signaling. Optogenetic elements function by converting electronic excitation of an embedded chromophore into structural changes on the microseconds to seconds time scale, which then modulate the activity of output domains responsible for biological signaling. Using time-resolved vibrational spectroscopy coupled with isotope labeling, we have mapped the structural evolution of the LOV2 domain of the flavin binding phototropin Avena sativa (AsLOV2) over 10 decades of time, reporting structural dynamics between 100 fs and 1 ms after optical excitation. The transient vibrational spectra contain contributions from both the flavin chromophore and the surrounding protein matrix. These contributions are resolved and assigned through the study of four different isotopically labeled samples. High signal-to-noise data permit the detailed analysis of kinetics associated with the light activated structural evolution. A pathway for the photocycle consistent with the data is proposed. The earliest events occur in the flavin binding pocket, where a subpicosecond perturbation of the protein matrix occurs. In this perturbed environment, the previously characterized reaction between triplet state isoalloxazine and an adjacent cysteine leads to formation of the adduct state; this step is shown to exhibit dispersive kinetics. This reaction promotes coupling of the optical excitation to successive time-dependent structural changes, initially in the β-sheet and then α-helix regions of the AsLOV2 domain, which ultimately gives rise to Jα-helix unfolding, yielding the signaling state. This model is tested through point mutagenesis, elucidating in particular the key mediating role played by Q513.
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Affiliation(s)
- Agnieszka A Gil
- Department of Chemistry, Stony Brook University , New York 11794-3400, United States
| | - Sergey P Laptenok
- School of Chemistry, University of East Anglia , Norwich, NR4 7TJ, U.K
| | - Jarrod B French
- Department of Chemistry, Stony Brook University , New York 11794-3400, United States
| | - James N Iuliano
- Department of Chemistry, Stony Brook University , New York 11794-3400, United States
| | - Andras Lukacs
- School of Chemistry, University of East Anglia , Norwich, NR4 7TJ, U.K.,Department of Biophysics, Medical School, University of Pecs , Szigeti ut 12, 7624 Pecs, Hungary
| | | | - Igor V Sazanovich
- Central Laser Facility, Research Complex at Harwell, Rutherford Appleton Laboratory , Didcot, Oxon OX11 0QX, U.K
| | - Gregory M Greetham
- Central Laser Facility, Research Complex at Harwell, Rutherford Appleton Laboratory , Didcot, Oxon OX11 0QX, U.K
| | - Adelbert Bacher
- Department Chemie, Technische Universität München , D-85747 Garching, Germany
| | - Boris Illarionov
- Institut für Biochemie und Lebensmittelchemie, Universität Hamburg , Grindelallee 117, D-20146 Hamburg, Germany
| | - Markus Fischer
- Institut für Biochemie und Lebensmittelchemie, Universität Hamburg , Grindelallee 117, D-20146 Hamburg, Germany
| | - Peter J Tonge
- Department of Chemistry, Stony Brook University , New York 11794-3400, United States
| | - Stephen R Meech
- School of Chemistry, University of East Anglia , Norwich, NR4 7TJ, U.K
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15
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Domratcheva T, Hartmann E, Schlichting I, Kottke T. Evidence for Tautomerisation of Glutamine in BLUF Blue Light Receptors by Vibrational Spectroscopy and Computational Chemistry. Sci Rep 2016; 6:22669. [PMID: 26947391 PMCID: PMC4780082 DOI: 10.1038/srep22669] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 02/16/2016] [Indexed: 02/02/2023] Open
Abstract
BLUF (blue light sensor using flavin) domains regulate the activity of various enzymatic effector domains in bacteria and euglenids. BLUF features a unique photoactivation through restructuring of the hydrogen-bonding network as opposed to a redox reaction or an isomerization of the chromophore. A conserved glutamine residue close to the flavin chromophore plays a central role in the light response, but the underlying modification is still unclear. We labelled this glutamine with (15)N in two representative BLUF domains and performed time-resolved infrared double difference spectroscopy. The assignment of the signals was conducted by extensive quantum chemical calculations on large models with 187 atoms reproducing the UV-vis and infrared signatures of BLUF photoactivation. In the dark state, the comparatively low frequency of 1,667 cm(-1) is assigned to the glutamine C=O accepting a hydrogen bond from tyrosine. In the light state, the signature of a tautomerised glutamine was extracted with the C=N stretch at ~1,691 cm(-1) exhibiting the characteristic strong downshift by (15)N labelling. Moreover, an indirect isotope effect on the flavin C4=O stretch was found. We conclude that photoactivation of the BLUF receptor does not only involve a rearrangement of hydrogen bonds but includes a change in covalent bonds of the protein.
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Affiliation(s)
- Tatiana Domratcheva
- Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, Jahnstraße 29, 69120, Heidelberg, Germany
| | - Elisabeth Hartmann
- Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, Jahnstraße 29, 69120, Heidelberg, Germany
| | - Ilme Schlichting
- Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, Jahnstraße 29, 69120, Heidelberg, Germany
| | - Tilman Kottke
- Physical and Biophysical Chemistry, Department of Chemistry, Bielefeld University, Universitäts straße 25, 33615 Bielefeld, Germany
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16
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Bacher A, Illarionov B, Eisenreich W, Fischer M. A roadmap to the isotopolog space of flavocoenzymes. Methods Mol Biol 2014; 1146:65-78. [PMID: 24764088 DOI: 10.1007/978-1-4939-0452-5_4] [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: 02/07/2023]
Abstract
Flavocoenzymes with selective or universal stable isotope labeling are important tools for the investigation of flavoproteins using a variety of spectroscopic methods. Numerous selectively labeled flavin isotopologs can be generated by the combined application of chemical synthesis and in vitro biotransformation using commercially available enzymes and/or recombinant riboflavin biosynthesis enzymes. Notably, the complex reaction sequences can be rapidly carried out using enzyme-assisted one-pot reaction strategies.
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Affiliation(s)
- Adelbert Bacher
- Department of Chemistry, Organic Chemistry & Biochemistry, Technische Universität München, Lichtenbergstraße 4, 85748 Garching, Munich, Germany,
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17
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Lukacs A, Brust R, Haigney A, Laptenok SP, Addison K, Gil A, Towrie M, Greetham GM, Tonge PJ, Meech SR. BLUF domain function does not require a metastable radical intermediate state. J Am Chem Soc 2014; 136:4605-15. [PMID: 24579721 PMCID: PMC4004230 DOI: 10.1021/ja4121082] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BLUF (blue light using flavin) domain proteins are an important family of blue light-sensing proteins which control a wide variety of functions in cells. The primary light-activated step in the BLUF domain is not yet established. A number of experimental and theoretical studies points to a role for photoinduced electron transfer (PET) between a highly conserved tyrosine and the flavin chromophore to form a radical intermediate state. Here we investigate the role of PET in three different BLUF proteins, using ultrafast broadband transient infrared spectroscopy. We characterize and identify infrared active marker modes for excited and ground state species and use them to record photochemical dynamics in the proteins. We also generate mutants which unambiguously show PET and, through isotope labeling of the protein and the chromophore, are able to assign modes characteristic of both flavin and protein radical states. We find that these radical intermediates are not observed in two of the three BLUF domains studied, casting doubt on the importance of the formation of a population of radical intermediates in the BLUF photocycle. Further, unnatural amino acid mutagenesis is used to replace the conserved tyrosine with fluorotyrosines, thus modifying the driving force for the proposed electron transfer reaction; the rate changes observed are also not consistent with a PET mechanism. Thus, while intermediates of PET reactions can be observed in BLUF proteins they are not correlated with photoactivity, suggesting that radical intermediates are not central to their operation. Alternative nonradical pathways including a keto-enol tautomerization induced by electronic excitation of the flavin ring are considered.
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Affiliation(s)
- Andras Lukacs
- Department of Chemistry, Stony Brook University , Stony Brook, New York 11794-3400, United States
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18
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Brust R, Haigney A, Lukacs A, Gil A, Hossain S, Addison K, Lai CT, Towrie M, Greetham G, Clark IP, Illarionov B, Bacher A, Kim RR, Fischer M, Simmerling C, Meech SR, Tonge PJ. Ultrafast Structural Dynamics of BlsA, a Photoreceptor from the Pathogenic Bacterium Acinetobacter baumannii. J Phys Chem Lett 2014; 5:220-224. [PMID: 24723998 PMCID: PMC3977573 DOI: 10.1021/jz4023738] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Accepted: 12/06/2013] [Indexed: 06/03/2023]
Abstract
Acinetobacter baumannii is an important human pathogen that can form biofilms and persist under harsh environmental conditions. Biofilm formation and virulence are modulated by blue light, which is thought to be regulated by a BLUF protein, BlsA. To understand the molecular mechanism of light sensing, we have used steady-state and ultrafast vibrational spectroscopy to compare the photoactivation mechanism of BlsA to the BLUF photosensor AppA from Rhodobacter sphaeroides. Although similar photocycles are observed, vibrational data together with homology modeling identify significant differences in the β5 strand in BlsA caused by photoactivation, which are proposed to be directly linked to downstream signaling.
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Affiliation(s)
- Richard Brust
- Department
of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | - Allison Haigney
- Department
of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | - Andras Lukacs
- School
of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
- Department
of Biophysics, Medical School, University
of Pecs, Pecs, Hungary
| | - Agnieszka Gil
- Department
of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | - Shahrier Hossain
- Department
of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | - Kiri Addison
- School
of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
| | - Cheng-Tsung Lai
- Department
of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | - Michael Towrie
- Central Laser
Facility, Research Complex at Harwell, Harwell Science and Innovation Campus, Didcot, Oxon OX11 0QX, United Kingdom
| | - Gregory
M. Greetham
- Central Laser
Facility, Research Complex at Harwell, Harwell Science and Innovation Campus, Didcot, Oxon OX11 0QX, United Kingdom
| | - Ian P. Clark
- Central Laser
Facility, Research Complex at Harwell, Harwell Science and Innovation Campus, Didcot, Oxon OX11 0QX, United Kingdom
| | - Boris Illarionov
- Institut für
Biochemie und Lebensmittelchemie, Universität
Hamburg, Grindelallee
117, D-20146 Hamburg, Germany
| | - Adelbert Bacher
- Institut für
Biochemie und Lebensmittelchemie, Universität
Hamburg, Grindelallee
117, D-20146 Hamburg, Germany
| | - Ryu-Ryun Kim
- Institut für
Biochemie und Lebensmittelchemie, Universität
Hamburg, Grindelallee
117, D-20146 Hamburg, Germany
| | - Markus Fischer
- Institut für
Biochemie und Lebensmittelchemie, Universität
Hamburg, Grindelallee
117, D-20146 Hamburg, Germany
| | - Carlos Simmerling
- Department
of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | - Stephen R. Meech
- School
of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
| | - Peter J. Tonge
- Department
of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States
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19
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Abstract
Light-induced difference Fourier transform infrared (FTIR) spectroscopy is a powerful, sensitive, and informative method to study structure-function relationships in photoreceptive proteins. Strong absorption of water in the IR region is always problematic in this method, but if water content in the sample is controlled during measurements, this method can provide useful information on a single protein-bound water molecule. We established three kinds of sample preparations: hydrated film, redissolved sample, and concentrated solution. Hydrated films were used for the measurements of LOV and BLUF domains, where accurate difference FTIR spectra were obtained in the whole mid-IR region (4,000-800 cm(-1)). Vibrations of S-H stretch of cysteine, O-H stretch of water, and O-H stretch of tyrosine provide important information on hydrogen bonds in these proteins. Redissolved samples were used for the measurements of (6-4) photolyase, in which enzymatic turnover takes place. From the illumination time-dependence of excess amount of substrate, it is possible to isolate the signal originating from the binding of enzyme to substrate. If proteins are less tolerant to drying, as for example cryptochromes of the DASH type, concentrated solution is used. Detailed methodological aspects in light-induced difference FTIR spectroscopy are reviewed by mainly focusing on our results.
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Affiliation(s)
- Daichi Yamada
- Department of Frontier Materials, Nagoya Institute of Technology, Showa-ku, Nagoya, 466-8555, Japan
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20
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Brust R, Lukacs A, Haigney A, Addison K, Gil A, Towrie M, Clark IP, Greetham G, Tonge PJ, Meech SR. Proteins in action: femtosecond to millisecond structural dynamics of a photoactive flavoprotein. J Am Chem Soc 2013; 135:16168-74. [PMID: 24083781 PMCID: PMC3837517 DOI: 10.1021/ja407265p] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Indexed: 01/07/2023]
Abstract
Living systems are fundamentally dependent on the ability of proteins to respond to external stimuli. The mechanism, the underlying structural dynamics, and the time scales for regulation of this response are central questions in biochemistry. Here we probe the structural dynamics of the BLUF domain found in several photoactive flavoproteins, which is responsible for light activated functions as diverse as phototaxis and gene regulation. Measurements have been made over 10 decades of time (from 100 fs to 1 ms) using transient vibrational spectroscopy. Chromophore (flavin ring) localized dynamics occur on the pico- to nanosecond time scale, while subsequent protein structural reorganization is observed over microseconds. Multiple time scales are observed for the dynamics associated with different vibrations of the protein, suggesting an underlying hierarchical relaxation pathway. Structural evolution in residues directly H-bonded to the chromophore takes place more slowly than changes in more remote residues. However, a point mutation which suppresses biological function is shown to 'short circuit' this structural relaxation pathway, suppressing the changes which occur further away from the chromophore while accelerating dynamics close to it.
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Affiliation(s)
- Richard Brust
- Department
of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | - Andras Lukacs
- School
of Chemistry, University of East Anglia,
Norwich Research Park, Norwich NR4 7TJ, United Kingdom
- Department
of Biophysics, Medical School, University
of Pecs, Szigeti ut 12, 7624 Pecs, Hungary
| | - Allison Haigney
- Department
of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | - Kiri Addison
- School
of Chemistry, University of East Anglia,
Norwich Research Park, Norwich NR4 7TJ, United Kingdom
| | - Agnieszka Gil
- Department
of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | - Michael Towrie
- Central
Laser Facility, Research Complex at Harwell, Harwell Science and Innovation Campus, Didcot, Oxon OX11
0QX, United Kingdom
| | - Ian P. Clark
- Central
Laser Facility, Research Complex at Harwell, Harwell Science and Innovation Campus, Didcot, Oxon OX11
0QX, United Kingdom
| | - Gregory
M. Greetham
- Central
Laser Facility, Research Complex at Harwell, Harwell Science and Innovation Campus, Didcot, Oxon OX11
0QX, United Kingdom
| | - Peter J. Tonge
- Department
of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | - Stephen R. Meech
- School
of Chemistry, University of East Anglia,
Norwich Research Park, Norwich NR4 7TJ, United Kingdom
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