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Abstract
Photoactive yellow protein (PYP) is a model photoreceptor. It binds a p-coumaric acid as a chromophore, thus enabling blue light sensing. The first discovered single-domain PYP from Halorhodospira halophila has been studied thoroughly in terms of its structural dynamics and photochemical properties. However, the evolutionary origins and biological role of PYP homologs are not well understood. Here, we show that PYP is an evolutionarily novel domain family of the ubiquitous PAS (Per-Arnt-Sim) superfamily. It likely originated from the phylum Myxococcota and was then horizontally transferred to representatives of a few other bacterial phyla. We show that PYP is associated with signal transduction either by domain fusion or by genome context. Key cellular functions modulated by PYP-initiated signal transduction pathways likely involve gene expression, motility, and biofilm formation. We identified three clades of the PYP family, one of which is poorly understood and potentially has novel functional properties. The Tyr42, Glu46, and Cys69 residues that are involved in p-coumaric acid binding in the model PYP from H. halophila are well conserved in the PYP family. However, we also identified cases where substitutions in these residues might have led to neofunctionalization, such as the proposed transition from light to redox sensing. Overall, this study provides definition, a newly built hidden Markov model, and the current genomic landscape of the PYP family and sets the stage for the future exploration of its signaling mechanisms and functional diversity. IMPORTANCE Photoactive yellow protein is a model bacterial photoreceptor. For many years, it was considered a prototypical model of the ubiquitous PAS domain superfamily. Here, we show that, in fact, the PYP family is evolutionarily novel, restricted to a few bacterial phyla and distinct from other PAS domains. We also reveal the diversity of PYP-containing signal transduction proteins and their potential mechanisms.
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2
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van Wilderen LJGW, Blankenburg L, Bredenbeck J. Femtosecond-to-millisecond mid-IR spectroscopy of Photoactive Yellow Protein uncovers structural micro-transitions of the chromophore's protonation mechanism. J Chem Phys 2022; 156:205103. [DOI: 10.1063/5.0091918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Protein structural dynamics can span many orders of magnitude in time. Photoactive Yellow Protein's (PYP) reversible photocycle encompasses picosecond isomerization of the light-absorbing chromophore as well as large scale protein backbone motions occurring on a millisecond timescale. Femtosecond-to-millisecond time-resolved mid-Infrared (IR) spectroscopy is employed here to uncover structural details of photocycle intermediates up to chromophore protonation and the first structural changes leading to formation of the partially-unfolded signalling state pB. The data show that a commonly thought stable transient photocycle intermediate is actually formed after a sequence of several smaller structural changes. We provide residue-specific spectroscopic evidence that protonation of the chromophore on a hundreds of microseconds timescale is delayed with respect to deprotonation of the nearby E46 residue. That implies that the direct proton donor is not E46 but most likely a water molecule. Such details may assist ongoing photocycle and protein folding simulation efforts on the complex and wide time-spanning photocycle of the model system PYP.
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3
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Mix LT, Hara M, Fuzell J, Kumauchi M, Kaledhonkar S, Xie A, Hoff WD, Larsen DS. Not All Photoactive Yellow Proteins Are Built Alike: Surprises and Insights into Chromophore Photoisomerization, Protonation, and Thermal Reisomerization of the Photoactive Yellow Protein Isolated from Salinibacter ruber. J Am Chem Soc 2021; 143:19614-19628. [PMID: 34780163 DOI: 10.1021/jacs.1c08910] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
We demonstrate that the Halorhodospira halophila (Hhal) photoactive yellow protein (PYP) is not representative of the greater PYP family. The photodynamics of the PYP isolated from Salinibacter ruber (Srub) is characterized with a comprehensive range of spectroscopic techniques including ultrafast transient absorption, photostationary light titrations, Fourier transform infrared, and cryokinetics spectroscopies. We demonstrate that the dark-adapted pG state consists of two subpopulations differing in the protonation state of the chromophore and that both are photoactive, with the protonated species undergoing excited-state proton transfer. However, the primary I0 photoproduct observed in the Hhal PYP photocycle is absent in the Srub PYP photodynamics, which indicates that this intermediate, while important in Hhal photodynamics, is not a critical intermediate in initiating all PYP photocycles. The excited-state lifetime of Srub PYP is the longest of any PYP resolved to date (∼30 ps), which we ascribe to the more constrained chromophore binding pocket of Srub PYP and the absence of the critical Arg52 residue found in Hhal PYP. The final stage of the Srub PYP photocycle involves the slowest known thermal dark reversion of a PYP (∼40 min vs 350 ms in Hhal PYP). This property allowed the characterization of a pH-dependent equilibrium between the light-adapted pB state with a protonated cis chromophore and a newly resolved pG' intermediate with a deprotonated cis chromophore and pG-like protein conformation. This result demonstates that protein conformational changes and chromophore deprotonation precede chromophore reisomerization during the thermal recovery of the PYP photocycle.
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Affiliation(s)
- L Tyler Mix
- Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, California 95616, United States
| | - Miwa Hara
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, Oklahoma 74078, United States
| | - Jack Fuzell
- Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, California 95616, United States
| | - Masato Kumauchi
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, Oklahoma 74078, United States
| | - Sandip Kaledhonkar
- Department of Physics, Oklahoma State University, Stillwater, Oklahoma 74078, United States
| | - Aihua Xie
- Department of Physics, Oklahoma State University, Stillwater, Oklahoma 74078, United States.,Center for Advanced Infrared Biology College of Arts and Sciences, Oklahoma State University, Stillwater, Oklahoma 74078, United States
| | - Wouter D Hoff
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, Oklahoma 74078, United States.,Center for Advanced Infrared Biology College of Arts and Sciences, Oklahoma State University, Stillwater, Oklahoma 74078, United States
| | - Delmar S Larsen
- Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, California 95616, United States
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4
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Ohmine I, Saito S. Dynamical Behavior of Water; Fluctuation, Reactions and Phase Transitions. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2021. [DOI: 10.1246/bcsj.20210269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Iwao Ohmine
- Institute for Molecular Science, Myodaiji, Okazaki, Aichi 444-8585, Japan
| | - Shinji Saito
- Institute for Molecular Science, Myodaiji, Okazaki, Aichi 444-8585, Japan
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5
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Kuramochi H, Takeuchi S, Kamikubo H, Kataoka M, Tahara T. Skeletal Structure of the Chromophore of Photoactive Yellow Protein in the Excited State Investigated by Ultraviolet Femtosecond Stimulated Raman Spectroscopy. J Phys Chem B 2021; 125:6154-6161. [PMID: 34102843 DOI: 10.1021/acs.jpcb.1c02828] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We studied ultrafast structural dynamics of photoactive yellow protein (PYP) using ultraviolet femtosecond stimulated Raman spectroscopy. By employing the Raman pump and probe pulses in the ultraviolet region, resonantly enhanced, rich vibrational features of the excited-state chromophore were observed in the fingerprint region. In contrast to the marked spectral change reported for the excited-state chromophore in solution, in the protein, all of the observed Raman bands in the fingerprint region did not show any noticeable spectral shifts nor band shape changes during the excited-state lifetime of PYP. This indicates that the significant skeletal change does not occur on the chromophore in the excited state of PYP and that the trans conformation is retained in its lifetime. Based on the femtosecond Raman data of PYP obtained so far, we discuss a comprehensive picture of the excited-state structural dynamics of PYP.
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Affiliation(s)
- Hikaru Kuramochi
- Molecular Spectroscopy Laboratory, RIKEN, 2-1 Hirosawa, Wako 351-0198, Japan.,Ultrafast Spectroscopy Research Team, RIKEN Center for Advanced Photonics (RAP), 2-1 Hirosawa, Wako 351-0198, Japan.,PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Satoshi Takeuchi
- Molecular Spectroscopy Laboratory, RIKEN, 2-1 Hirosawa, Wako 351-0198, Japan.,Ultrafast Spectroscopy Research Team, RIKEN Center for Advanced Photonics (RAP), 2-1 Hirosawa, Wako 351-0198, Japan
| | - Hironari Kamikubo
- Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan
| | - Mikio Kataoka
- Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan
| | - Tahei Tahara
- Molecular Spectroscopy Laboratory, RIKEN, 2-1 Hirosawa, Wako 351-0198, Japan.,Ultrafast Spectroscopy Research Team, RIKEN Center for Advanced Photonics (RAP), 2-1 Hirosawa, Wako 351-0198, Japan
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6
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Buhrke D, Hildebrandt P. Probing Structure and Reaction Dynamics of Proteins Using Time-Resolved Resonance Raman Spectroscopy. Chem Rev 2019; 120:3577-3630. [PMID: 31814387 DOI: 10.1021/acs.chemrev.9b00429] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The mechanistic understanding of protein functions requires insight into the structural and reaction dynamics. To elucidate these processes, a variety of experimental approaches are employed. Among them, time-resolved (TR) resonance Raman (RR) is a particularly versatile tool to probe processes of proteins harboring cofactors with electronic transitions in the visible range, such as retinal or heme proteins. TR RR spectroscopy offers the advantage of simultaneously providing molecular structure and kinetic information. The various TR RR spectroscopic methods can cover a wide dynamic range down to the femtosecond time regime and have been employed in monitoring photoinduced reaction cascades, ligand binding and dissociation, electron transfer, enzymatic reactions, and protein un- and refolding. In this account, we review the achievements of TR RR spectroscopy of nearly 50 years of research in this field, which also illustrates how the role of TR RR spectroscopy in molecular life science has changed from the beginning until now. We outline the various methodological approaches and developments and point out current limitations and potential perspectives.
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Affiliation(s)
- David Buhrke
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Straße des 17, Juni 135, D-10623 Berlin, Germany
| | - Peter Hildebrandt
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Straße des 17, Juni 135, D-10623 Berlin, Germany
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7
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Fang C, Tang L, Chen C. Unveiling coupled electronic and vibrational motions of chromophores in condensed phases. J Chem Phys 2019; 151:200901. [PMID: 31779327 DOI: 10.1063/1.5128388] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The quest for capturing molecular movies of functional systems has motivated scientists and engineers for decades. A fundamental understanding of electronic and nuclear motions, two principal components of the molecular Schrödinger equation, has the potential to enable the de novo rational design for targeted functionalities of molecular machines. We discuss the development and application of a relatively new structural dynamics technique, femtosecond stimulated Raman spectroscopy with broadly tunable laser pulses from the UV to near-IR region, in tracking the coupled electronic and vibrational motions of organic chromophores in solution and protein environments. Such light-sensitive moieties hold broad interest and significance in gaining fundamental knowledge about the intramolecular and intermolecular Hamiltonian and developing effective strategies to control macroscopic properties. Inspired by recent experimental and theoretical advances, we focus on the in situ characterization and spectroscopy-guided tuning of photoacidity, excited state proton transfer pathways, emission color, and internal conversion via a conical intersection.
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Affiliation(s)
- Chong Fang
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, USA
| | - Longteng Tang
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, USA
| | - Cheng Chen
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, USA
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8
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Kirpich JS, Chang CW, Madsen D, Gottlieb SM, Martin SS, Rockwell NC, Lagarias JC, Larsen DS. Noncanonical Photodynamics of the Orange/Green Cyanobacteriochrome Power Sensor NpF2164g7 from the PtxD Phototaxis Regulator of Nostoc punctiforme. Biochemistry 2018; 57:2636-2648. [PMID: 29633829 DOI: 10.1021/acs.biochem.7b01252] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Forward and reverse primary (<10 ns) and secondary (>10 ns) photodynamics of cyanobacteriochrome (CBCR) NpF2164g7 were characterized by global analysis of ultrafast broadband transient absorption measurements. NpF2164g7 is the most C-terminal bilin-binding GAF domain in the Nostoc punctiforme phototaxis sensor PtxD (locus Npun_F2164). Although a member of the canonical red/green CBCR subfamily phylogenetically, NpF2164g7 exhibits an orange-absorbing 15ZPo dark-adapted state instead of the typical red-absorbing 15ZPr dark-adapted state characteristic of this subfamily. The green-absorbing 15EPg photoproduct of NpF2164g7 is unstable, allowing this CBCR domain to function as a power sensor. Photoexcitation of the 15ZPo state triggers inhomogeneous excited-state dynamics with three spectrally and temporally distinguishable pathways to generate the light-adapted 15EPg state in high yield (estimated at 25-30%). Although observed in other CBCR domains, the inhomogeneity in NpF2164g7 extends far into secondary relaxation dynamics (10 ns -1 ms) through to formation of 15EPg. In the reverse direction, the primary dynamics after photoexcitation of 15EPg are qualitatively similar to those of other red/green CBCRs, but secondary dynamics involve a "pre-equilibrium" step before regenerating 15ZPo. The anomalous photodynamics of NpF2164g7 may reflect an evolutionary adaptation of CBCR sensors that function as broadband light intensity sensors.
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Mix LT, Carroll EC, Morozov D, Pan J, Gordon WR, Philip A, Fuzell J, Kumauchi M, van Stokkum I, Groenhof G, Hoff WD, Larsen DS. Excitation-Wavelength-Dependent Photocycle Initiation Dynamics Resolve Heterogeneity in the Photoactive Yellow Protein from Halorhodospira halophila. Biochemistry 2018; 57:1733-1747. [PMID: 29465990 DOI: 10.1021/acs.biochem.7b01114] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Photoactive yellow proteins (PYPs) make up a diverse class of blue-light-absorbing bacterial photoreceptors. Electronic excitation of the p-coumaric acid chromophore covalently bound within PYP results in triphasic quenching kinetics; however, the molecular basis of this behavior remains unresolved. Here we explore this question by examining the excitation-wavelength dependence of the photodynamics of the PYP from Halorhodospira halophila via a combined experimental and computational approach. The fluorescence quantum yield, steady-state fluorescence emission maximum, and cryotrapping spectra are demonstrated to depend on excitation wavelength. We also compare the femtosecond photodynamics in PYP at two excitation wavelengths (435 and 475 nm) with a dual-excitation-wavelength-interleaved pump-probe technique. Multicompartment global analysis of these data demonstrates that the excited-state photochemistry of PYP depends subtly, but convincingly, on excitation wavelength with similar kinetics with distinctly different spectral features, including a shifted ground-state beach and altered stimulated emission oscillator strengths and peak positions. Three models involving multiple excited states, vibrationally enhanced barrier crossing, and inhomogeneity are proposed to interpret the observed excitation-wavelength dependence of the data. Conformational heterogeneity was identified as the most probable model, which was supported with molecular mechanics simulations that identified two levels of inhomogeneity involving the orientation of the R52 residue and different hydrogen bonding networks with the p-coumaric acid chromophore. Quantum calculations were used to confirm that these inhomogeneities track to altered spectral properties consistent with the experimental results.
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Affiliation(s)
- L Tyler Mix
- Department of Chemistry , University of California, Davis , One Shields Avenue , Davis , California 95616 , United States
| | - Elizabeth C Carroll
- Department of Chemistry , University of California, Davis , One Shields Avenue , Davis , California 95616 , United States
| | - Dmitry Morozov
- Department of Chemistry and NanoScience Center , University of Jyväskylä , P.O. Box 35, 40014 Jyväskylä , Finland
| | - Jie Pan
- Department of Chemistry , University of California, Davis , One Shields Avenue , Davis , California 95616 , United States
| | | | | | - Jack Fuzell
- Department of Chemistry , University of California, Davis , One Shields Avenue , Davis , California 95616 , United States
| | - Masato Kumauchi
- Department of Microbiology and Molecular Genetics , Oklahoma State University , Stillwater , Oklahoma 74078 , United States
| | - Ivo van Stokkum
- Faculty of Sciences , Vrije Universiteit Amsterdam , De Boelelaan 1081 , 1081 HV Amsterdam , The Netherlands
| | - Gerrit Groenhof
- Department of Chemistry and NanoScience Center , University of Jyväskylä , P.O. Box 35, 40014 Jyväskylä , Finland
| | - Wouter D Hoff
- Department of Microbiology and Molecular Genetics , Oklahoma State University , Stillwater , Oklahoma 74078 , United States
| | - Delmar S Larsen
- Department of Chemistry , University of California, Davis , One Shields Avenue , Davis , California 95616 , United States
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10
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Tamura K, Hayashi S. Role of Bulk Water Environment in Regulation of Functional Hydrogen-Bond Network in Photoactive Yellow Protein. J Phys Chem B 2015; 119:15537-49. [DOI: 10.1021/acs.jpcb.5b07555] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Koichi Tamura
- Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Shigehiko Hayashi
- Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
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11
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Creelman M, Kumauchi M, Hoff WD, Mathies RA. Chromophore Dynamics in the PYP Photocycle from Femtosecond Stimulated Raman Spectroscopy. J Phys Chem B 2014; 118:659-67. [DOI: 10.1021/jp408584v] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Mark Creelman
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
| | - Masato Kumauchi
- Department
of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, Oklahoma 74078, United States
| | - Wouter D. Hoff
- Department
of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, Oklahoma 74078, United States
| | - Richard A. Mathies
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
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12
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Wei L, Wang H, Chen X, Fang W, Wang H. A comprehensive study of isomerization and protonation reactions in the photocycle of the photoactive yellow protein. Phys Chem Chem Phys 2014; 16:25263-72. [DOI: 10.1039/c4cp03495c] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
A comprehensive picture of the overall photocycle was obtained to reveal a wide range of structural signals in the photoactive yellow protein.
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Affiliation(s)
- Lili Wei
- Key Laboratory of Theoretical and Computational Photochemistry of Ministry of Education
- Department of Chemistry
- Beijing Normal University
- Beijing, China
| | - Hongjuan Wang
- Key Laboratory of Theoretical and Computational Photochemistry of Ministry of Education
- Department of Chemistry
- Beijing Normal University
- Beijing, China
| | - Xuebo Chen
- Key Laboratory of Theoretical and Computational Photochemistry of Ministry of Education
- Department of Chemistry
- Beijing Normal University
- Beijing, China
| | - Weihai Fang
- Key Laboratory of Theoretical and Computational Photochemistry of Ministry of Education
- Department of Chemistry
- Beijing Normal University
- Beijing, China
| | - Haobin Wang
- Department of Chemistry and Biochemistry
- New Mexico State University
- Las Cruces, USA
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13
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Naseem S, Laurent AD, Carroll EC, Vengris M, Kumauchi M, Hoff WD, Krylov AI, Larsen DS. Photo-isomerization upshifts the pKa of the Photoactive Yellow Protein chromophore to contribute to photocycle propagation. J Photochem Photobiol A Chem 2013. [DOI: 10.1016/j.jphotochem.2013.06.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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14
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Preketes NK, Biggs JD, Ren H, Andricioaei I, Mukamel S. Simulations of Two-dimensional Infrared and Stimulated Resonance Raman Spectra of Photoactive Yellow Protein. Chem Phys 2013; 422. [PMID: 24244064 DOI: 10.1016/j.chemphys.2012.09.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
We present simulations of one and two-dimensional infrared (2DIR) and stimulated resonance Raman (SRR) spectra of the dark state (pG) and early red-shifted intermediate (pR) of photoactive yellow protein (PYP). Shifts in the amide I and Glu46 COOH stretching bands distinguish between pG and pR in the IR absorption and 2DIR spectra. The one-dimensional SRR spectra are similar to the spontaneous RR spectra. The two-dimensional SRR spectra show large changes in cross peaks involving the C=O stretch of the two species and are more sensitive to the chromophore structure than 2DIR spectra.
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15
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Liu J, Yabushita A, Taniguchi S, Chosrowjan H, Imamoto Y, Sueda K, Miyanaga N, Kobayashi T. Ultrafast Time-Resolved Pump–Probe Spectroscopy of PYP by a Sub-8 fs Pulse Laser at 400 nm. J Phys Chem B 2013; 117:4818-26. [DOI: 10.1021/jp4001016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Jun Liu
- Advanced Ultrafast Laser Research
Center, University of Electro-Communications, Chofugaoka 1-5-1, Chofu, Tokyo 182-8585 Japan
- State Key Laboratory of High
Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
- Core Research for Evolutional
Science and Technology (CREST), Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Atsushi Yabushita
- Department of Electrophysics, National Chiao Tung University, 1001 Ta Hsueh Road,
Hsinchu 300, Taiwan
| | - Seiji Taniguchi
- Institute
for Laser Technology, Osaka University,
Yamadaoka 2-6, Suita Osaka, 565-0871
Japan
| | - Haik Chosrowjan
- Institute
for Laser Technology, Osaka University,
Yamadaoka 2-6, Suita Osaka, 565-0871
Japan
| | - Yasushi Imamoto
- Department of Biophysics,
Graduate
School of Science, Kyoto University, Kitashirakawa-Oiwake,
Sakyo, Kyoto 606-8502 Japan
| | - Keiichi Sueda
- Institute of Laser Engineering, Osaka University, Yamadakami 2-6, Suita 565-0871, Ibaraki
567-0047, Japan
| | - Noriaki Miyanaga
- Institute of Laser Engineering, Osaka University, Yamadakami 2-6, Suita 565-0871, Ibaraki
567-0047, Japan
| | - Takayoshi Kobayashi
- Advanced Ultrafast Laser Research
Center, University of Electro-Communications, Chofugaoka 1-5-1, Chofu, Tokyo 182-8585 Japan
- Core Research for Evolutional
Science and Technology (CREST), Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
- Department of Electrophysics, National Chiao Tung University, 1001 Ta Hsueh Road,
Hsinchu 300, Taiwan
- Institute of Laser Engineering, Osaka University, Yamadakami 2-6, Suita 565-0871, Ibaraki
567-0047, Japan
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16
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Ganim Z. Single-molecule vibrational spectroscopy adds structural resolution to the optical trap. Biophys J 2013; 104:4-5. [PMID: 23332052 DOI: 10.1016/j.bpj.2012.09.044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Revised: 09/12/2012] [Accepted: 09/20/2012] [Indexed: 12/01/2022] Open
Abstract
The ability to apply forces on single molecules with an optical trap is combined with the endogenous structural resolution of Raman spectroscopy in an article in this issue, and applied to measure the Raman spectrum of ds-DNA during force-extension.
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Affiliation(s)
- Ziad Ganim
- Physik Department, Technische Universität München, Garching, Germany.
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17
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Abstract
Protein conformational switches alter their shape upon receiving an input signal, such as ligand binding, chemical modification, or change in environment. The apparent simplicity of this transformation--which can be carried out by a molecule as small as a thousand atoms or so--belies its critical importance to the life of the cell as well as its capacity for engineering by humans. In the realm of molecular switches, proteins are unique because they are capable of performing a variety of biological functions. Switchable proteins are therefore of high interest to the fields of biology, biotechnology, and medicine. These molecules are beginning to be exploited as the core machinery behind a new generation of biosensors, functionally regulated enzymes, and "smart" biomaterials that react to their surroundings. As inspirations for these designs, researchers continue to analyze existing examples of allosteric proteins. Recent years have also witnessed the development of new methodologies for introducing conformational change into proteins that previously had none. Herein we review examples of both natural and engineered protein switches in the context of four basic modes of conformational change: rigid-body domain movement, limited structural rearrangement, global fold switching, and folding-unfolding. Our purpose is to highlight examples that can potentially serve as platforms for the design of custom switches. Accordingly, we focus on inducible conformational changes that are substantial enough to produce a functional response (e.g., in a second protein to which it is fused), yet are relatively simple, structurally well-characterized, and amenable to protein engineering efforts.
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Affiliation(s)
| | - Stewart N. Loh
- Department of Biochemistry & Molecular Biology, State University of New York Upstate Medical University, 750 East Adams Street, Syracuse, NY 13210 (USA), Tel: (315)464-8731, Fax: (315)464-8750
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19
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Abstract
Recent neutron diffraction studies of photoactive yellow protein (PYP) proposed that the H bond between protonated Glu46 and the chromophore [ionized p-coumaric acid (pCA)] was a low-barrier H bond (LBHB). Using the atomic coordinates of the high-resolution crystal structure, we analyzed the energetics of the short H bond by two independent methods: electrostatic pK(a) calculations and a quantum mechanical/molecular mechanical (QM/MM) approach. (i) In the QM/MM optimized geometry, we reproduced the two short H-bond distances of the crystal structure: Tyr42-pCA (2.50 Å) and Glu46-pCA (2.57 Å). However, the H atoms obviously belonged to the Tyr or Glu moieties, and were not near the midpoint of the donor and acceptor atoms. (ii) The potential-energy curves of the two H bonds resembled those of standard asymmetric double-well potentials, which differ from those of LBHB. (iii) The calculated pK(a) values for Glu46 and pCA were 8.6 and 5.4, respectively. The pK(a) difference was unlikely to satisfy the prerequisite for LBHB. (iv) The LBHB in PYP was originally proposed to stabilize the ionized pCA because deprotonated Arg52 cannot stabilize it. However, the calculated pK(a) of Arg52 and QM/MM optimized geometry suggested that Arg52 was protonated on the protein surface. The short H bond between Glu46 and ionized pCA in the PYP ground state could be simply explained by electrostatic stabilization without invoking LBHB.
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Singhal K, Bhatt K, Kang Z, Hoff W, Xie A, Kalkan AK. Structural Dynamics of a Single Photoreceptor Protein Molecule Monitored With Surface-Enhanced Raman Scattering Substrates. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-1077-l10-04] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTPhotoactive yellow protein (PYP) is a small cytosolic photoreceptor that actuates the negative phototactic response in its host organism Halorhodospira halophila. It has an optical absorption maximum at 446 nm (blue light). We report an initial study of the photocycle of PYP at the single molecule level using “high enhancement factor” surface-enhanced Raman scattering (SERS)-active nanostructures with 514 nm laser excitation. The SERS-active “nanometal-on-semiconductor” structures are prepared employing a redox technique on thin germanium films, coated on glass slides. Single molecule spectra are observed in terms of sudden appearance of discernable Raman peaks with spectral fluctuations. The single molecule spectra capture protonation, photo-isomerization, and H-bond breaking - the steps that are instrumental in the photocycle of PYP. This is indicative of single PYP molecules diffusing to high-enhancement-factor SERS sites, and undergoing photo-cycle under 514 nm excitation.
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Kamiya M, Ohmine I. A Molecular Dynamics Study for the Structure Determination of the Signaling State in the Photocycle of Photoactive Yellow Protein. J Phys Chem B 2010; 114:6594-600. [DOI: 10.1021/jp910018d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Motoshi Kamiya
- Chemistry Department, Nagoya University, 1, Furocho, Chikusa-ku, Nagoya, Japan 464-8602, and Fukui Institute for Fundamental Chemistry, Kyoto University, 34-4, Takano Nishihiraku-machi, Sakyo-ku, Kyoto, Japan 606-8103
| | - Iwao Ohmine
- Chemistry Department, Nagoya University, 1, Furocho, Chikusa-ku, Nagoya, Japan 464-8602, and Fukui Institute for Fundamental Chemistry, Kyoto University, 34-4, Takano Nishihiraku-machi, Sakyo-ku, Kyoto, Japan 606-8103
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22
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Vreede J, Juraszek J, Bolhuis PG. Predicting the reaction coordinates of millisecond light-induced conformational changes in photoactive yellow protein. Proc Natl Acad Sci U S A 2010; 107:2397-402. [PMID: 20133754 PMCID: PMC2823881 DOI: 10.1073/pnas.0908754107] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Understanding the dynamics of large-scale conformational changes in proteins still poses a challenge for molecular simulations. We employ transition path sampling of explicit solvent molecular dynamics trajectories to obtain atomistic insight in the reaction network of the millisecond timescale partial unfolding transition in the photocycle of the bacterial sensor photoactive yellow protein. Likelihood maximization analysis predicts the best model for the reaction coordinates of each substep as well as tentative transition states, without further simulation. We find that the unfolding of the alpha-helical region 43-51 is followed by sequential solvent exposure of both Glu46 and the chromophore. Which of these two residues is exposed first is correlated with the presence of a salt bridge that is part of the N-terminal domain. Additional molecular dynamics simulations indicate that the exposure of the chromophore does not result in a productive pathway. We discuss several possibilities for experimental validation of these predictions. Our results open the way for studying millisecond conformational changes in other medium-sized (signaling) proteins.
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Affiliation(s)
- Jocelyne Vreede
- Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands.
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Abstract
Low-barrier hydrogen bonds (LBHBs) have been proposed to play roles in protein functions, including enzymatic catalysis and proton transfer. Transient formation of LBHBs is expected to stabilize specific reaction intermediates. However, based on experimental results and theoretical considerations, arguments against the importance of LBHB in proteins have been raised. The discrepancy is caused by the absence of direct identification of the hydrogen atom position. Here, we show by high-resolution neutron crystallography of photoactive yellow protein (PYP) that a LBHB exists in a protein, even in the ground state. We identified approximately 87% (819/942) of the hydrogen positions in PYP and demonstrated that the hydrogen bond between the chromophore and E46 is a LBHB. This LBHB stabilizes an isolated electric charge buried in the hydrophobic environment of the protein interior. We propose that in the excited state the fast relaxation of the LBHB into a normal hydrogen bond is the trigger for photo-signal propagation to the protein moiety. These results give insights into the novel roles of LBHBs and the mechanism of the formation of LBHBs.
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25
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Hoersch D, Otto H, Cusanovich MA, Heyn MP. Distinguishing chromophore structures of photocycle intermediates of the photoreceptor PYP by transient fluorescence and energy transfer. J Phys Chem B 2008; 112:9118-25. [PMID: 18605685 DOI: 10.1021/jp801174z] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The cinnamoyl chromophore is the light-activated switch of the photoreceptor photoactive yellow protein (PYP) and isomerizes during the functional cycle. The fluorescence of W119, the only tryptophan of PYP, is quenched by energy transfer to the chromophore. This depends on the chromophore's transition dipole moment orientation and spectrum, both of which change during the photocycle. The transient fluorescence of W119 thus serves as a sensitive kinetic monitor of the chromophore's structure and orientation and was used for the first time to investigate the photocycle kinetics. From these data and measurements of the ps-fluorescence decay with background illumination (470 nm) we determined the fluorescence lifetimes of W119 in the I(1) and I (1') intermediates. Two coexisting distinct chromophore structures were proposed for the I(1) photointermediate from time-resolved X-ray diffraction ( Ihee, H., et al. Proc. Natl. Acad. Sci. U.S.A., 2005, 102, 7145 ): one with two hydrogen bonds to E46 and Y42, and a second with only one H-bond to Y42 and a different orientation. Only for the first of these is the calculated fluorescence lifetime of 0.22 ns in good agreement with the observed one of 0.26 ns. The second structure has a predicted lifetime of 0.71 ns. Thus, we conclude that in solution only the first I(1) structure occurs. The high resolution structure of the I(1') intermediate, the decay product of I(1) at alkaline pH, is still unknown. We predict from the observed lifetime of 1.3 ns that the chromophore structure of I(1') is quite similar to that of the I(2) intermediate, and I(1') should thus be considered as the alkaline (deprotonated) form of I(2).
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Affiliation(s)
- Daniel Hoersch
- Biophysics Group, Department of Physics, Freie Universitat Berlin, Arnimallee 14, 14195 Berlin, Germany
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26
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Putschögl M, Zirak P, Penzkofer A. Absorption and emission behaviour of trans-p-coumaric acid in aqueous solutions and some organic solvents. Chem Phys 2008. [DOI: 10.1016/j.chemphys.2007.10.031] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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27
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Imamoto Y, Kataoka M. Structure and photoreaction of photoactive yellow protein, a structural prototype of the PAS domain superfamily. Photochem Photobiol 2007; 83:40-9. [PMID: 16939366 DOI: 10.1562/2006-02-28-ir-827] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Photoactive yellow protein (PYP) is a water-soluble photosensor protein found in purple photosynthetic bacteria. Unlike bacterial rhodopsins, photosensor proteins composed of seven transmembrane helices and a retinal chromophore in halophilic archaebacteria, PYP is a highly soluble globular protein. The alpha/beta fold structure of PYP is a structural prototype of the PAS domain superfamily, many members of which function as sensors for various kinds of stimuli. To absorb a photon in the visible region, PYP has a p-coumaric acid chromophore binding to the cysteine residue via a thioester bond. It exists in a deprotonated trans form in the dark. The primary photochemical event is photo-isomerization of the chromophore from trans to cis form. The twisted cis chromophore in early intermediates is relaxed and finally protonated. Consequently, the chromophore becomes electrostatically neutral and rearrangement of the hydrogen-bonding network triggers overall structural change of the protein moiety, in which local conformational change around the chromophore is propagated to the N-terminal region. Thus, it is an ideal model for protein conformational changes that result in functional change, responding to stimuli and expressing physiological activity. In this paper, recent progress in investigation of the photoresponse of PYP is reviewed.
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Affiliation(s)
- Yasushi Imamoto
- Graduate School of Materials Science, Nara Institute of Science and Technology, Ikoma, Nara, Japan.
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28
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Borucki B, Otto H, Meyer TE, Cusanovich MA, Heyn MP. Sensitive circular dichroism marker for the chromophore environment of photoactive yellow protein: assignment of the 307 and 318 nm bands to the n --> pi* transition of the carbonyl. J Phys Chem B 2007; 109:629-33. [PMID: 16851055 DOI: 10.1021/jp046515k] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The absorption and CD spectra of wild-type PYP, apo-PYP, and the mutants, E46Q and M100A, were measured between 250 and 550 nm. At neutral pH, the two very weak absorption bands of wild-type PYP at 307 and 318 nm (epsilon(max) = 600 +/- 100 M(-1) cm(-1) at 318 nm) are associated with quite strong positive CD bands (Deltaepsilon(max) approximately 6.8 M(-1) cm(-1)). Both sets of bands are absent in the apoprotein. On the basis of this evidence, we assign these optical signals to the n --> pi* transition of the oxygen of the carbonyl group of the 4-hydroxycinnamic acid chromophore, which is expected to be electric dipole forbidden but magnetic dipole allowed. The progression of narrow bands at 307 and 318 nm with a shoulder in the CD around 329 nm is due to vibrational fine structure with a frequency of about 1050 +/- 50 cm(-1). This is the carbonyl stretch frequency in the electronically excited state and is well-known from the vibrational structure in the CD spectra of carbonyl compounds. The positive sign of the CD in the near UV is in accordance with the octant rule and the high-resolution X-ray structure, if we assume that the NH group of cysteine 69 to which the carbonyl is hydrogen bonded is the principle perturbant. Similar absorption and CD spectra were observed in the range of 300-340 nm for the mutants E46Q and M100A at neutral pH. Protonation of the trans chromophore by lowering the pH in the dark (without photoisomerization) broadens the 307 and 318 nm CD bands in the mutant E46Q but does not significantly affect their positions or alter their sign. For the long-lived I(2) photointermediate of the mutant M100A with protonated cis chromophore, we observed that the sign of the rotational strength in the 310-320 nm range is negative (i.e., opposite to that in the dark state with trans chromophore). This suggests that the light-induced isomerization of the chromophore, which leads to breaking of the hydrogen bond with the backbone amide of C69, brings the carbonyl into a new protein environment with different asymmetry than in the unbleached protein. The observed change in sign is mainly due to this effect, but a change in chromophore twist may also contribute. Thus, the 318 nm CD signal is a sensitive marker for the environment of the chromophore carbonyl, which samples various environments and configurations during the photocycle.
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Affiliation(s)
- Berthold Borucki
- Biophysics Group, Physics Department, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany
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29
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Mizuno M, Hamada N, Tokunaga F, Mizutani Y. Picosecond Protein Response to the Chromophore Isomerization of Photoactive Yellow Protein: Selective Observation of Tyrosine and Tryptophan Residues by Time-Resolved Ultraviolet Resonance Raman Spectroscopy. J Phys Chem B 2007; 111:6293-6. [PMID: 17523627 DOI: 10.1021/jp072939d] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Picosecond time-resolved ultraviolet resonance Raman (UVRR) spectra of photoactive yellow protein (PYP) were measured. UVRR bands attributed to the vibration of tyrosine and tryptophan residues showed a spectral change upon photoreaction. It was found that the hydrogen-bond strength between the chromophore and Y42 increases in the pG* state. The ultrafast change in the tryptophan band revealed that a photoinduced structural change of the chromophore had propagated to the W119 region, located 12 A from the chromophore, within picoseconds.
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30
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Adesokan AA, Pan D, Fredj E, Mathies RA, Gerber RB. Anharmonic Vibrational Calculations Modeling the Raman Spectra of Intermediates in the Photoactive Yellow Protein (PYP) Photocycle. J Am Chem Soc 2007; 129:4584-94. [PMID: 17378558 DOI: 10.1021/ja066903v] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The role of anharmonic effects in the vibrational spectroscopy of the dark state and two major chromophore intermediates of the photoactive yellow protein (PYP) photocycle is examined via ab initio vibrational self-consistent field (VSCF) calculations and time-resolved resonance Raman spectroscopy. For the first time, anharmonicity is considered explicitly in calculating the vibrational spectra of an ensemble consisting of the PYP chromophore surrounded by model compounds used as mimics of the important active-site residues. Predictions of vibrational frequencies on an ab initio corrected semiempirical potential energy surface show remarkable agreement with experimental frequencies for all three states, thus shedding light on the potential along the reaction path. For example, calculated frequencies for vibrational modes of the red-shifted intermediate, PYPL, exhibit an overall average error of 0.82% from experiment. Upon analysis of anharmonicity patterns in the PYP modes we observe a decrease in anharmonicity in the C8-C9 stretching mode nu29 (trans-cis isomerization marker mode) with the onset of the cis configuration in PYPL. This can be attributed to the loss of the hydrogen-bonding character of the adjacent C9-O2 to the methylamine (Cys69 backbone). For several of the modes, the anharmonicity is mostly due to mode-mode coupling, while for others it is mostly intrinsic. This study shows the importance of the inclusion of anharmonicity in theoretical spectroscopic calculations, and the sensitivity of experiments to anharmonicity. The characterization of protein active-site residues by small molecular mimics provides an acceptable chemical structural representation for biomolecular spectroscopy calculations.
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Affiliation(s)
- Adeyemi A Adesokan
- Department of Chemistry, University of California at Irvine, Irvine, CA 92697, USA
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31
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Kamiya M, Saito S, Ohmine I. Proton Transfer and Associated Molecular Rearrangements in the Photocycle of Photoactive Yellow Protein: Role of Water Molecular Migration on the Proton Transfer Reaction. J Phys Chem B 2007; 111:2948-56. [PMID: 17388419 DOI: 10.1021/jp066256u] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The mechanism of the proton transfer and the concomitant molecular structural and hydrogen bond rearrangements after the photoisomerization of the chromophore in the photocycle of photoactive yellow protein are theoretically investigated by using the QM/MM method and molecular dynamics calculations. The free energy surface along this proton-transfer process is determined. This work suggests the important role of the water molecular migration into the moiety of chromophore, which facilitates proton transfer by the hydrogen bond rearrangement and the hydration of the pB' state.
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Affiliation(s)
- Motoshi Kamiya
- Chemistry Department, Nagoya University, 1 Furocho, Chikusaku, Nagoya 464-8602, Japan
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32
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Borucki B, Joshi CP, Otto H, Cusanovich MA, Heyn MP. The transient accumulation of the signaling state of photoactive yellow protein is controlled by the external pH. Biophys J 2006; 91:2991-3001. [PMID: 16829563 PMCID: PMC1578485 DOI: 10.1529/biophysj.106.086645] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The signaling state of the photoreceptor photoactive yellow protein is the long-lived intermediate I(2)'. The pH dependence of the equilibrium between the transient photocycle intermediates I(2) and I(2)' was investigated. The formation of I(2)' from I(2) is accompanied by a major conformational change. The kinetics and intermediates of the photocycle and of the photoreversal were measured by transient absorption spectroscopy from pH 4.6 to 8.4. Singular value decomposition (SVD) analysis of the data at pH 7 showed the presence of three spectrally distinguishable species: I(1), I(2), and I(2)'. Their spectra were determined using the extrapolated difference method. I(2) and I(2)' have electronic absorption spectra, with maxima at 370 +/- 5 and 350 +/- 5 nm, respectively. Formation of the signaling state is thus associated with a change in the environment of the protonated chromophore. The time courses of the I(1), I(2), and I(2)' intermediates were determined from the wavelength-dependent transient absorbance changes at each pH, assuming that their spectra are pH-independent. After the formation of I(2)' ( approximately 2 ms), these three intermediates are in equilibrium and decay together to the initial dark state. The equilibrium between I(2) and I(2)' is pH dependent with a pK(a) of 6.4 and with I(2)' the main species above this pK(a). Measurements of the pH dependence of the photoreversal kinetics with a second flash of 355 nm at a delay of 20 ms confirm this pK(a) value. I(2) and I(2)' are photoreversed with reversal times of approximately 55 micros and several hundred microseconds, respectively. The corresponding signal amplitudes are pH dependent with a pK(a) of approximately 6.1. Photoreversal from I(2)' dominates above the pK(a). The transient accumulation of I(2)', the active state of photoactive yellow protein, is thus controlled by the proton concentration. The rate constant k(3) for the recovery to the initial dark state also has a pK(a) of approximately 6.3. This equality of the equilibrium and kinetic pK(a) values is not accidental and suggests that k(3) is proportional to [I(2)'].
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Affiliation(s)
- Berthold Borucki
- Biophysics Group, Department of Physics, Freie Universität Berlin, 14195 Berlin, Germany
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Abstract
The photoactive yellow protein (PYP) is the photoreceptor protein responsible for initiating the blue-light repellent response of the Halorhodospira halophila bacterium. Optical excitation of the intrinsic chromophore in PYP, p-coumaric acid, leads to the initiation of a photocycle that comprises several distinct intermediates. The dynamical processes responsible for the initiation of the PYP photocycle have been explored with several time-resolved techniques, which include ultrafast electronic and vibrational spectroscopies. Ultrafast electronic spectroscopies, such as pump-visible probe, pump-dump-visible probe, and fluorescence upconversion, are useful in identifying the timescales and connectivity of the transient intermediates, while ultrafast vibrational spectroscopies link these intermediates to dynamic structures. Herein, we present the use of these techniques for exploring the initial dynamics of PYP, and show how these techniques provide the basis for understanding the complex relationship between protein and chromophore, which ultimately results in biological function.
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Affiliation(s)
- Delmar S Larsen
- Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands.
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34
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Shimizu N, Imamoto Y, Harigai M, Kamikubo H, Yamazaki Y, Kataoka M. pH-dependent Equilibrium between Long Lived Near-UV Intermediates of Photoactive Yellow Protein. J Biol Chem 2006; 281:4318-25. [PMID: 16368695 DOI: 10.1074/jbc.m506403200] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The long lived intermediate (signaling state) of photoactive yellow protein (PYP(M)), which is formed in the photocycle, was characterized at various pHs. PYP(M) at neutral pH was in equilibrium between two spectroscopically distinct states. Absorption maxima of the acidic form (PYP(M)(acid)) and alkaline form (PYP(M)(alkali)) were located at 367 and 356 nm, respectively. Equilibrium was represented by the Henderson-Hasselbalch equation, in which apparent pK(a) was 6.4. Content of alpha- and/or beta-structure of PYP(M)(acid) was significantly greater than PYP(M)(alkali) as demonstrated by the molar ellipticity at 222 nm. In addition, changes in amide I and II modes of beta-structure in the difference Fourier transform infrared spectra for formation of PYP(M)(acid) was smaller than that of PYP(M)(alkali). The vibrational mode at 1747 cm(-1) of protonated Glu-46 was found as a small band for PYP(M)(acid) but not for PYP(M)(alkali), suggesting that Glu-46 remains partially protonated in PYP(M)(acid), whereas it is fully deprotonated in PYP(M)(alkali). Small angle x-ray scattering measurements demonstrated that the radius of gyration of PYP(M)(acid) was 15.7 Angstroms, whereas for PYP(M)(alkali) it was 16.2 Angstroms. These results indicate that PYP(M)(acid) assumes a more ordered and compact structure than PYP(M)(alkali). Binding of citrate shifts this equilibrium toward PYP(M)(alkali). UV-visible absorption spectra and difference infrared spectra of the long lived intermediate formed from E46Q mutant was consistent with those of PYP(M)(acid), indicating that the mutation shifts this equilibrium toward PYP(M)(acid). Alterations in the nature of PYP(M) by pH, citrate, and mutation of Glu-46 are consistently explained by the shift of the equilibrium between PYP(M)(acid) and PYP(M)(alkali).
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Affiliation(s)
- Nobutaka Shimizu
- Graduate School of Materials Science, Nara Institute of Science and Technology, Ikoma, Japan
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35
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Borucki B. Proton transfer in the photoreceptors phytochrome and photoactive yellow protein. Photochem Photobiol Sci 2006; 5:553-66. [PMID: 16761084 DOI: 10.1039/b603846h] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Light-induced activation of the photoreceptors phytochrome and photoactive yellow protein (PYP) is accompanied by protonation changes of the respective chromophores and key residues in the protein moiety. For both systems, proton exchange with the external medium could be observed with pH electrode measurements and with UV-visible absorption spectroscopy using appropriate pH indicator dyes. From these signals, the stoichiometry of proton release and uptake, respectively, was determined by different calibration procedures which will be presented and discussed. Kinetic information on these processes is only available from time-resolved measurements with pH indicator dyes. Vibrational spectroscopy methods such as Fourier transform infrared spectroscopy and resonance Raman scattering provided information on the protonation state of individual functional groups suggesting that internal proton transfer processes are involved as well. Deuterium kinetic isotope effects that occurred in the Pr --> Pfr phototransformation of the bacteriophytochromes Cph1 and Agp1 were consistent with proton transfer reactions as rate-limiting steps. In contrast, the apparent rate constants in the photocycle of PYP exhibited only small kinetic isotope effects that could not be interpreted conclusively. Possible mechanisms of proton transfer in the activation of phytochrome and PYP will be discussed.
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Affiliation(s)
- Berthold Borucki
- Biophysics Group, Department of Physics, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany.
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36
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Naumann H, Klare JP, Engelhard M, Hildebrandt P, Murgida DH. Time-resolved methods in Biophysics. 1. A novel pump and probe surface-enhanced resonance Raman approach for studying biological photoreceptors. Photochem Photobiol Sci 2006; 5:1103-8. [PMID: 17136274 DOI: 10.1039/b607807a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This article describes a method, based on surface-enhanced resonance Raman (SERR) spectroscopy, for studying the reaction dynamics of photoreceptors immobilized on metal electrodes. Time resolution and fresh sample conditions are achieved by synchronizing the rotational and translational motion of a novel kinematic electrode with the duration and time delay between the pump and probe events. The power and sensitivity of the method is illustrated by studying the photocycle of the sensory photoreceptor NpSRII and its sensitivity to the applied electric field. The results are compared with time-resolved resonance Raman measurements in solution.
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Affiliation(s)
- Hendrik Naumann
- Technische Universität Berlin, Institut für Chemie, Max Volmer Laboratorium für Biophysikalische Chemie, Sekr. PC 14, Strasse des 17. Juni 135, D-10623, Berlin, Germany
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37
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Vreede J, Crielaard W, Hellingwerf KJ, Bolhuis PG. Predicting the signaling state of photoactive yellow protein. Biophys J 2005; 88:3525-35. [PMID: 15722437 PMCID: PMC1305499 DOI: 10.1529/biophysj.104.055103] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
As a bacterial blue light sensor the photoactive yellow protein (PYP) undergoes conformational changes upon signal transduction. The absorption of a photon triggers a series of events that are initially localized around the protein chromophore, extends to encompass the whole protein within microseconds, and leads to the formation of the transient pB signaling state. We study the formation of this signaling state pB by molecular simulation and predict its solution structure. Conventional straightforward molecular dynamics is not able to address this formation process due to the long (microsecond) timescales involved, which are (partially) caused by the presence of free energy barriers between the metastable states. To overcome these barriers, we employed the parallel tempering (or replica exchange) method, thus enabling us to predict qualitatively the formation of the PYP signaling state pB. In contrast to the receptor state pG of PYP, the characteristics of this predicted pB structure include a wide open chromophore-binding pocket, with the chromophore and Glu(46) fully solvent-exposed. In addition, loss of alpha-helical structure occurs, caused by the opening motion of the chromophore-binding pocket and the disruptive interaction of the negatively charged Glu(46) with the backbone atoms in the hydrophobic core of the N-terminal cap. Recent NMR experiments agree very well with these predictions.
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Affiliation(s)
- Jocelyne Vreede
- Swammerdam Institute for Life Sciences, and van 't Hoff Institute of Molecular Sciences, University of Amsterdam, Amsterdam, The Netherlands
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38
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Unno M, Kumauchi M, Hamada N, Tokunaga F, Yamauchi S. Resonance Raman Evidence for Two Conformations Involved in the L Intermediate of Photoactive Yellow Protein. J Biol Chem 2004; 279:23855-8. [PMID: 15096497 DOI: 10.1074/jbc.c400137200] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The blue light receptor photoactive yellow protein (PYP) displays a photocycle that involves several intermediate states. Here we report resonance Raman spectroscopic investigations of the short-lived red-shifted intermediate denoted PYP(L). We have found that the Raman bands of the carbonyl C=O stretching mode nu(11) as well as the C=C stretching mode nu(13) for the chromophore can be resolved into two peaks, and the ratio of the two components varies as a function of pH with pK(a) approximately 6. The isotope effects on the resonance Raman spectra have confirmed a deprotonated cis-chromophore for the two components. The results indicate the presence of two conformations in the active site of PYP(L). The normal coordinate calculations based on the density functional theory provide a structural model for the two conformations, where the low pH form is possibly an active structure for the protonation reaction generating a following intermediate in the photocycle.
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Affiliation(s)
- Masashi Unno
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan.
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