1
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Cetin E, Atilgan AR, Atilgan C. DHFR Mutants Modulate Their Synchronized Dynamics with the Substrate by Shifting Hydrogen Bond Occupancies. J Chem Inf Model 2022; 62:6715-6726. [PMID: 35984987 PMCID: PMC9795552 DOI: 10.1021/acs.jcim.2c00507] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Antibiotic resistance is a global health problem in which mutations occurring in functional proteins render drugs ineffective. The working mechanisms of the arising mutants are seldom apparent; a methodology to decipher these mechanisms systematically would render devising therapies to control the arising mutational pathways possible. Here we utilize Cα-Cβ bond vector relaxations obtained from moderate length MD trajectories to determine conduits for functionality of the resistance conferring mutants of Escherichia coli dihydrofolate reductase. We find that the whole enzyme is synchronized to the motions of the substrate, irrespective of the mutation introducing gain-of-function or loss-of function. The total coordination of the motions suggests changes in the hydrogen bond dynamics with respect to the wild type as a possible route to determine and classify the mode-of-action of individual mutants. As a result, nine trimethoprim-resistant point mutations arising frequently in evolution experiments are categorized. One group of mutants that display the largest occurrence (L28R, W30G) work directly by modifying the dihydrofolate binding region. Conversely, W30R works indirectly by the formation of the E139-R30 salt bridge which releases energy resulting from tight binding by distorting the binding cavity. A third group (D27E, F153S, I94L) arising as single, resistance invoking mutants in evolution experiment trajectories allosterically and dynamically affects a hydrogen bonding motif formed at residues 59-69-71 which in turn modifies the binding site dynamics. The final group (I5F, A26T, R98P) consists of those mutants that have properties most similar to the wild type; these only appear after one of the other mutants is fixed on the protein structure and therefore display clear epistasis. Thus, we show that the binding event is governed by the entire enzyme dynamics while the binding site residues play gating roles. The adjustments made in the total enzyme in response to point mutations are what make quantifying and pinpointing their effect a hard problem. Here, we show that hydrogen bond dynamics recorded on sub-μs time scales provide the necessary fingerprints to decipher the various mechanisms at play.
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2
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Sato R, Mori Y, Matsui R, Okimoto N, Yamamoto J, Taiji M. Theoretical insights into the DNA repair function of Arabidopsis thaliana cryptochrome-DASH. Biophys Physicobiol 2020; 17:113-124. [PMID: 33194514 PMCID: PMC7610064 DOI: 10.2142/biophysico.bsj-2020010] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 08/28/2020] [Indexed: 12/01/2022] Open
Abstract
Following the discovery of cryptochrome-DASH (CRYD) as a new type of blue-light receptor cryptochrome, theoretical and experimental findings on CRYD have been reported. Early studies identified CRYD as highly homologous to the DNA repair enzyme photolyases (PLs), suggesting the involvement of CRYD in DNA repair. However, an experimental study reported that CRYD does not exhibit DNA repair activity in vivo. Successful PL-mediated DNA repair requires: (i) the recognition of UV-induced DNA lesions and (ii) an electron transfer reaction. If either of them is inefficient, the DNA repair activity will be low. To elucidate the functional differences between CRYD and PL, we theoretically investigated the electron transfer reactivity and DNA binding affinity of CRYD and also performed supplementary experiments. The average electronic coupling matrix elements value for Arabidopsis thaliana CRYD (AtCRYD) was estimated to be 5.3 meV, comparable to that of Anacystis nidulans cyclobutane pyrimidine dimer PLs (AnPL) at 4.5 meV, indicating similar electron transfer reactivities. We also confirmed the DNA repair activity of AtCRYD for UV-damaged single-stranded DNA by the experimental analysis. In addition, we investigated the dynamic behavior of AtCRYD and AnPL in complex with double-stranded DNA using molecular dynamics simulations and observed the formation of a transient salt bridge between protein and DNA in AtCRYD, in contrast to AnPL in which it was formed stably. We suggested that the instability of the salt bridge between protein and DNA will lead to reduced DNA binding affinity for AtCRYD.
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Affiliation(s)
- Ryuma Sato
- Center for Biosystems Dynamics Research, RIKEN, Suita, Osaka 565-0874, Japan
| | - Yoshiharu Mori
- School of Pharmacy, Kitasato University, Minato-ku, Tokyo 108-8641, Japan
| | - Risa Matsui
- Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Noriaki Okimoto
- Center for Biosystems Dynamics Research, RIKEN, Suita, Osaka 565-0874, Japan
| | - Junpei Yamamoto
- Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Makoto Taiji
- Center for Biosystems Dynamics Research, RIKEN, Suita, Osaka 565-0874, Japan
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3
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Heyes DJ, Lakavath B, Hardman SJO, Sakuma M, Hedison TM, Scrutton NS. Photochemical Mechanism of Light-Driven Fatty Acid Photodecarboxylase. ACS Catal 2020; 10:6691-6696. [PMID: 32905273 PMCID: PMC7469136 DOI: 10.1021/acscatal.0c01684] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 05/18/2020] [Indexed: 01/06/2023]
Abstract
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Fatty
acid photodecarboxylase (FAP) is a promising target for the
production of biofuels and fine chemicals. It contains a flavin adenine
dinucleotide cofactor and catalyzes the blue-light-dependent decarboxylation
of fatty acids to generate the corresponding alkane. However, little
is known about the catalytic mechanism of FAP, or how light is used
to drive enzymatic decarboxylation. Here, we have used a combination
of time-resolved and cryogenic trapping UV–visible absorption
spectroscopy to characterize a red-shifted flavin intermediate observed
in the catalytic cycle of FAP. We show that this intermediate can
form below the “glass transition” temperature of proteins,
whereas the subsequent decay of the species proceeds only at higher
temperatures, implying a role for protein motions in the decay of
the intermediate. Solvent isotope effect measurements, combined with
analyses of selected site-directed variants of FAP, suggest that the
formation of the red-shifted flavin species is directly coupled with
hydrogen atom transfer from a nearby active site cysteine residue,
yielding the final alkane product. Our study suggests that this cysteine
residue forms a thiolate-flavin charge-transfer species, which is
assigned as the red-shifted flavin intermediate. Taken together, our
data provide insights into light-dependent decarboxylase mechanisms
catalyzed by FAP and highlight important considerations in the (re)design
of flavin-based photoenzymes.
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Affiliation(s)
- Derren J. Heyes
- Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester M1 7DN, U.K
| | - Balaji Lakavath
- Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester M1 7DN, U.K
| | - Samantha J. O. Hardman
- Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester M1 7DN, U.K
| | - Michiyo Sakuma
- Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester M1 7DN, U.K
| | - Tobias M. Hedison
- Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester M1 7DN, U.K
| | - Nigel S. Scrutton
- Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester M1 7DN, U.K
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4
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Sato R, Kitoh-Nishioka H, Ando K, Yamato T. Electron Transfer Pathways of Cyclobutane Pyrimidine Dimer Photolyase Revisited. J Phys Chem B 2018; 122:6912-6921. [PMID: 29890068 DOI: 10.1021/acs.jpcb.8b04333] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The photoinduced electron transfer (ET) reaction of cyclobutane pyrimidine dimer (CPD) photolyase plays an essential role in its DNA repair reaction, and the molecular mechanism of the ET reaction has attracted a large number of experimental and theoretical studies. We investigated the quantum mechanical nature of their ET reactions, characterized by multiple ET pathways of the CPD photolyase derived from Anacystis nidulans. Using the generalized Mulliken-Hush (GMH) method and the bridge green function (GF) methods, we estimated the electronic coupling matrix element, TDA, to be 36 ± 30 cm-1 from the donor (FADH-) to the acceptor (CPD). The estimated ET time was 386 ps, in good agreement with the experimental value (250 ps) in the literature. Furthermore, we performed the molecular dynamics (MD) simulations and ab initio molecular orbital (MO) calculations, and explored the electron tunneling pathway. We examined 20 different structures during the MD trajectory and quantitatively evaluated the electron tunneling currents for each of them. As a result, we demonstrated that the ET route via Asn349 was the dominant pathway among the five major routes via (Adenine/Asn349), (Adenine/Glu283), (Adenine/Glu283/Asn349/Met353), (Met353/Asn349), and (Asn349), indicating that Asn349 is an essential amino acid residue in the ET reaction.
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Affiliation(s)
- Ryuma Sato
- Department of Physics, Graduate School of Science , Nagoya University , Furo-cho, Chikusa-ku , Nagoya 464-8602 , Japan
| | - Hirotaka Kitoh-Nishioka
- Center for Computational Sciences , University of Tsukuba 1-1-1 Tennodai , Tsukuba , Ibaraki 305-8577 , Japan
| | - Koji Ando
- Department of Information and Sciences , Tokyo Woman's Christian University , 2-6-1 Zempukuji, Suginami-ku , Tokyo 167-8585 , Japan
| | - Takahisa Yamato
- Department of Physics, Graduate School of Science , Nagoya University , Furo-cho, Chikusa-ku , Nagoya 464-8602 , Japan.,Institute of Genetics and Molecular and Cellular Biology , University of Strasbourg , 1 rue Laurent Fries Parc d'Innovation 67404 Illkirch, Cedex, France
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5
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Kundu M, He TF, Lu Y, Wang L, Zhong D. Short-Range Electron Transfer in Reduced Flavodoxin: Ultrafast Nonequilibrium Dynamics Coupled with Protein Fluctuations. J Phys Chem Lett 2018; 9:2782-2790. [PMID: 29722985 PMCID: PMC7304529 DOI: 10.1021/acs.jpclett.8b00882] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Short-range electron transfer (ET) in proteins is an ultrafast process on the similar time scales as local protein-solvent fluctuation, and thus the two dynamics are coupled. Here we use semiquinone flavodoxin and systematically characterized the photoinduced redox cycle with 11 mutations of different aromatic electron donors (tryptophan and tyrosine) and local residues to change redox properties. We observed the forward and backward ET dynamics in a few picoseconds, strongly following a stretched behavior resulting from a coupling between local environment relaxations and these ET processes. We further observed the hot vibrational-state formation through charge recombination and the subsequent cooling dynamics also in a few picoseconds. Combined with the ET studies in oxidized flavodoxin, these results coherently reveal the evolution of the ET dynamics from single to stretched exponential behaviors and thus elucidate critical time scales for the coupling. The observed hot vibration-state formation is robust and should be considered in all photoinduced back ET processes in flavoproteins.
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6
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Rousseau BJG, Shafei S, Migliore A, Stanley RJ, Beratan DN. Determinants of Photolyase's DNA Repair Mechanism in Mesophiles and Extremophiles. J Am Chem Soc 2018; 140:2853-2861. [PMID: 29401372 DOI: 10.1021/jacs.7b11926] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Light-driven DNA repair by extremophilic photolyases is of tremendous importance for understanding the early development of life on Earth. The mechanism for flavin adenine dinucleotide repair of DNA lesions is the subject of debate and has been studied mainly in mesophilic species. In particular, the role of adenine in the repair process is poorly understood. Using molecular docking, molecular dynamics simulations, electronic structure calculations, and electron tunneling pathways analysis, we examined adenine's role in DNA repair in four photolyases that thrive at different temperatures. Our results indicate that the contribution of adenine to the electronic coupling between the flavin and the cyclobutane pyrimidine dimer lesion to be repaired is significant in three (one mesophilic and two extremophilic) of the four enzymes studied. Our analysis suggests that thermophilic and hyperthermophilic photolyases have evolved structurally to preserve the functional position (and thus the catalytic function) of adenine at their high temperatures of operation. Water molecules can compete with adenine in establishing the strongest coupling pathway for the electron transfer repair process, but the adenine contribution remains substantial. The present study also reconciles prior seemingly contradictory conclusions on the role of adenine in mesophile electron transfer repair reactions, showing how adenine-mediated superexchange is conformationally gated.
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Affiliation(s)
| | | | | | - Robert J Stanley
- Department of Chemistry, Temple University , Philadelphia, Pennsylvania 19122, United States
| | - David N Beratan
- Department of Biochemistry, Duke University , Durham, North Carolina 27710, United States
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7
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Wang X, Gong A, Luo W, Wang H, Lin C, Liu XY, Lin Y. Remote activation of nanoparticulate biomimetic activity by light triggered pH-jump. Chem Commun (Camb) 2018; 54:8641-8644. [DOI: 10.1039/c8cc04279a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
By incorporating flash photolysis reagents, a facile and versatile method for the photo-regulation of pH-dependent activities of artificial enzymes is presented.
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Affiliation(s)
- Xiaopei Wang
- Research Institute for Biomimetics and Soft Matter
- Fujian Provincial Key Laboratory for Soft Functional Materials Research
- College of Physical Science and Technology
- College of Materials
- Xiamen University
| | - Ao Gong
- Research Institute for Biomimetics and Soft Matter
- Fujian Provincial Key Laboratory for Soft Functional Materials Research
- College of Physical Science and Technology
- College of Materials
- Xiamen University
| | - Wenhao Luo
- Research Institute for Biomimetics and Soft Matter
- Fujian Provincial Key Laboratory for Soft Functional Materials Research
- College of Physical Science and Technology
- College of Materials
- Xiamen University
| | - Haiqing Wang
- Research Institute for Biomimetics and Soft Matter
- Fujian Provincial Key Laboratory for Soft Functional Materials Research
- College of Physical Science and Technology
- College of Materials
- Xiamen University
| | - Changxu Lin
- Research Institute for Biomimetics and Soft Matter
- Fujian Provincial Key Laboratory for Soft Functional Materials Research
- College of Physical Science and Technology
- College of Materials
- Xiamen University
| | - Xiang Yang Liu
- Research Institute for Biomimetics and Soft Matter
- Fujian Provincial Key Laboratory for Soft Functional Materials Research
- College of Physical Science and Technology
- College of Materials
- Xiamen University
| | - Youhui Lin
- Research Institute for Biomimetics and Soft Matter
- Fujian Provincial Key Laboratory for Soft Functional Materials Research
- College of Physical Science and Technology
- College of Materials
- Xiamen University
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8
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Chu JW, Yang H. Identifying the structural and kinetic elements in protein large-amplitude conformational motions. INT REV PHYS CHEM 2017. [DOI: 10.1080/0144235x.2017.1283885] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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9
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Yamada D, Dokainish HM, Iwata T, Yamamoto J, Ishikawa T, Todo T, Iwai S, Getzoff ED, Kitao A, Kandori H. Functional Conversion of CPD and (6-4) Photolyases by Mutation. Biochemistry 2016; 55:4173-83. [PMID: 27431478 DOI: 10.1021/acs.biochem.6b00361] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ultraviolet (UV) light from the sun damages DNA by forming a cyclobutane pyrimidine dimer (CPD) and pyrimidine(6-4)pyrimidone photoproducts [(6-4) PP]. Photolyase (PHR) enzymes utilize near-UV/blue light for DNA repair, which is initiated by light-induced electron transfer from the fully reduced flavin adenine dinucleotide chromophore. Despite similar structures and repair mechanisms, the functions of PHR are highly selective; CPD PHR repairs CPD, but not (6-4) PP, and vice versa. In this study, we attempted functional conversion between CPD and (6-4) PHRs. We found that a triple mutant of (6-4) PHR is able to repair the CPD photoproduct, though the repair efficiency is 1 order of magnitude lower than that of wild-type CPD PHR. Difference Fourier transform infrared spectra for repair demonstrate the lack of secondary structural alteration in the mutant, suggesting that the triple mutant gains substrate binding ability while it does not gain the optimized conformational changes from light-induced electron transfer to the release of the repaired DNA. Interestingly, the (6-4) photoproduct is not repaired by the reverse mutation of CPD PHR, and eight additional mutations (total of 11 mutations) introduced into CPD PHR are not sufficient. The observed asymmetric functional conversion is interpreted in terms of a more complex repair mechanism for (6-4) repair, which was supported by quantum chemical/molecular mechanical calculation. These results suggest that CPD PHR may represent an evolutionary origin for photolyase family proteins.
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Affiliation(s)
- Daichi Yamada
- Department of Frontier Materials, Nagoya Institute of Technology , Showa-ku, Nagoya 466-8555, Japan
| | - Hisham M Dokainish
- Institute of Molecular and Cellular Biosciences, The University of Tokyo , 1-1-1, Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Tatsuya Iwata
- Department of Frontier Materials, Nagoya Institute of Technology , Showa-ku, Nagoya 466-8555, Japan.,OptoBioTechnology Research Center, Nagoya Institute of Technology , Showa-ku, Nagoya 466-8555, Japan
| | - Junpei Yamamoto
- Graduate School of Engineering Science, Osaka University , Toyonaka, Osaka 560-8531, Japan
| | - Tomoko Ishikawa
- Department of Radiation Biology and Medical Genetics, Graduate School of Medicine, Osaka University , Osaka 565-0871, Japan
| | - Takeshi Todo
- Department of Radiation Biology and Medical Genetics, Graduate School of Medicine, Osaka University , Osaka 565-0871, Japan
| | - Shigenori Iwai
- Graduate School of Engineering Science, Osaka University , Toyonaka, Osaka 560-8531, Japan
| | - Elizabeth D Getzoff
- Department of Integrative Structural and Computational Biology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute , La Jolla, California 92037, United States
| | - Akio Kitao
- Institute of Molecular and Cellular Biosciences, The University of Tokyo , 1-1-1, Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Hideki Kandori
- Department of Frontier Materials, Nagoya Institute of Technology , Showa-ku, Nagoya 466-8555, Japan.,OptoBioTechnology Research Center, Nagoya Institute of Technology , Showa-ku, Nagoya 466-8555, Japan
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10
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Abstract
Photolyase is a flavin photoenzyme that repairs two DNA base damage products induced by ultraviolet (UV) light: cyclobutane pyrimidine dimers and 6-4 photoproducts. With femtosecond spectroscopy and site-directed mutagenesis, investigators have recently made significant advances in our understanding of UV-damaged DNA repair, and the entire enzymatic dynamics can now be mapped out in real time. For dimer repair, six elementary steps have been characterized, including three electron transfer reactions and two bond-breaking processes, and their reaction times have been determined. A unique electron-tunneling pathway was identified, and the critical residues in modulating the repair function at the active site were determined. The dynamic synergy between the elementary reactions for maintaining high repair efficiency was elucidated, and the biological nature of the flavin active state was uncovered. For 6-4 photoproduct repair, a proton-coupled electron transfer repair mechanism has been revealed. The elucidation of electron transfer mechanisms and two repair photocycles is significant and provides a molecular basis for future practical applications, such as in rational drug design for curing skin cancer.
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Affiliation(s)
- Dongping Zhong
- Department of Physics, Department of Chemistry and Biochemistry, and Programs of Biophysics, Chemical Physics, and Biochemistry, The Ohio State University, Columbus, Ohio 43210;
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11
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Abstract
Photolyases, a class of flavoproteins, use blue light to repair two types of ultraviolet-induced DNA damage, a cyclobutane pyrimidine dimer (CPD) and a pyrimidine-pyrimidone (6-4) photoproduct (6-4PP). In this perspective, we review the recent progress in the repair dynamics and mechanisms of both types of DNA restoration by photolyases. We first report the spectroscopic characterization of flavin in various redox states and the active-site solvation dynamics in photolyases. We then systematically summarize the detailed repair dynamics of damaged DNA by photolyases and a biomimetic system through resolving all elementary steps on ultrafast timescales, including multiple intermolecular electron- and proton-transfer reactions and bond-breaking and -making processes. We determined the unique electron tunneling pathways, identified the key functional residues and revealed the molecular origin of high repair efficiency, and thus elucidate the molecular mechanisms and repair photocycles at the most fundamental level. We finally conclude that the active sites of photolyases, unlike the aqueous solution for the biomimetic system, provide a unique electrostatic environment and local flexibility and thus a dedicated synergy for all elementary dynamics to maximize the repair efficiency. This repair photomachine is the first enzyme that the entire functional evolution is completely mapped out in real time.
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Affiliation(s)
- Zheyun Liu
- Department of Physics, Department of Chemistry and Biochemistry, and Programs of Biophysics, Chemical Physics, and Biochemistry, The Ohio State University, Columbus, Ohio 43210, USA.
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12
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Computational modeling of photoexcitation in DNA single and double strands. Top Curr Chem (Cham) 2015; 356:89-122. [PMID: 24647841 DOI: 10.1007/128_2014_533] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
The photoexcitation of DNA strands triggers extremely complex photoinduced processes, which cannot be understood solely on the basis of the behavior of the nucleobase building blocks. Decisive factors in DNA oligomers and polymers include collective electronic effects, excitonic coupling, hydrogen-bonding interactions, local steric hindrance, charge transfer, and environmental and solvent effects. This chapter surveys recent theoretical and computational efforts to model real-world excited-state DNA strands using a variety of established and emerging theoretical methods. One central issue is the role of localized vs delocalized excitations and the extent to which they determine the nature and the temporal evolution of the initial photoexcitation in DNA strands.
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13
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Wang J, Du X, Pan W, Wang X, Wu W. Photoactivation of the cryptochrome/photolyase superfamily. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY C-PHOTOCHEMISTRY REVIEWS 2015. [DOI: 10.1016/j.jphotochemrev.2014.12.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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14
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Kohse S, Neubauer A, Lochbrunner S, Kragl U. Improving the Time Resolution for Remote Control of Enzyme Activity by a Nanosecond Laser-Induced pH Jump. ChemCatChem 2014. [DOI: 10.1002/cctc.201402442] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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15
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Wang H, Chen X, Fang W. Excited-state proton coupled electron transfer between photolyase and the damaged DNA through water wire: a photo-repair mechanism. Phys Chem Chem Phys 2014; 16:25432-41. [PMID: 25341360 DOI: 10.1039/c4cp04130e] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The photolyase enzyme absorbs blue light to repair damaged DNA through a cyclic electron transfer reaction. A description of the underlying mechanism has proven to be a challenging issue for both experimental and theoretical studies. In the present work, combined CASPT2//CASSCF/AMBER (QM/MM) calculations have been performed for damaged DNA in photolyase. A proton-coupled electron transfer (PCET) mechanism has been determined for restoring cyclobutane pyrimidine dimer (CPD) to two normal thymine bases by irradiation of photolyase. A well-defined water wire between FADH(-) and CPD was determined as a bridge to assist the PCET process within FADH(-) and thereby trigger the forward electron transfer to CPD. The subsequent CPD splitting and the alternation of the H-bond pattern proceed in a concerted way, which makes the productive backward electron transfer occur on an ultrafast timescale. A local minimum of SCT((1)ππ*)-LMin was identified on the pathway of the futile backward electron transfer (BET), which is stabilized by the strong H-bond interaction between the water wire and CPD. As a result, the futile BET process is endothermic by ∼18.0 kcal mol(-1), which is responsible for a 2.4 ns timescale inferred experimentally for the futile BET process. Besides the unbiased interpretation for the majority of the experimental findings, the present study provides a new excited-state PCET mechanism, which leads to a significant step toward a deeper understanding of the photo-repair process of damaged-DNA by the photolyase enzyme.
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Affiliation(s)
- Hongjuan Wang
- Key Laboratory of Theoretical and Computational Photochemistry of Ministry of Education, Department of Chemistry, Beijing Normal University, Xin-wai-da-jie No. 19, Beijing, 100875, China.
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16
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Meador JA, Baldwin AJ, Pakulski JD, Jeffrey WH, Mitchell DL, Douki T. The significance of the Dewar valence photoisomer as a UV radiation-induced DNA photoproduct in marine microbial communities. Environ Microbiol 2014; 16:1808-20. [PMID: 24517516 DOI: 10.1111/1462-2920.12414] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Revised: 01/11/2014] [Accepted: 01/27/2014] [Indexed: 11/28/2022]
Abstract
Induction of pyrimidine dimers in DNA by solar UV radiation has drastic effects on microorganisms. To better define the nature of these DNA photoproducts in marine bacterioplankton and eukaryotes, a study was performed during a cruise along a latitudinal transect in the Pacific Ocean. The frequency of all possible cyclobutane pyrimidine dimers, pyrimidine (6-4) pyrimidone photoproducts (64PPs) and their related Dewar valence isomers (DEWs) was determined by high-performance liquid chromatography-mass spectrometry. Studied samples were bacterioplankton and eukaryotic fractions isolated from sea water either collected before sunrise or exposed to ambient sunlight from sunrise to sunset. Isolated DNA dosimeters were also exposed to daily sunlight for comparison purposes. A first major result was the observation in all samples of large amounts of DEWs, a class of photoproducts rarely considered outside photochemical studies. Evidence was obtained for a major role of UVA in the formation of these photoisomerization products of 64PPs. Considerations on the ratio between the different classes of photoproducts in basal and induced DNA damage suggests that photoenzymatic repair (PER) is an important DNA repair mechanism used by marine microorganisms occupying surface seawater in the open ocean. This result emphasizes the biological role of DEWs which are very poor substrate for PER.
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Affiliation(s)
- Jarah A Meador
- Center for Radiological Research, Columbia University, New York, NY, USA
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17
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Fraikin GY, Strakhovskaya MG, Rubin AB. Biological photoreceptors of light-dependent regulatory processes. BIOCHEMISTRY (MOSCOW) 2013; 78:1238-53. [DOI: 10.1134/s0006297913110047] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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18
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Kohse S, Neubauer A, Pazidis A, Lochbrunner S, Kragl U. Photoswitching of Enzyme Activity by Laser-Induced pH-Jump. J Am Chem Soc 2013; 135:9407-11. [DOI: 10.1021/ja400700x] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Stefanie Kohse
- Department of Chemistry, University of Rostock, Albert-Einstein-Straße
3a, D-18059 Rostock, Germany
- Faculty
of Interdisciplinary Research, University of Rostock, Wismarsche Straße 8, D-18057
Rostock, Germany
| | - Antje Neubauer
- Institute of Physics, University of Rostock, Universitaetsplatz 3, D-18055
Rostock, Germany
| | - Alexandra Pazidis
- Institute of Physics, University of Rostock, Universitaetsplatz 3, D-18055
Rostock, Germany
| | - Stefan Lochbrunner
- Institute of Physics, University of Rostock, Universitaetsplatz 3, D-18055
Rostock, Germany
- Faculty
of Interdisciplinary Research, University of Rostock, Wismarsche Straße 8, D-18057
Rostock, Germany
| | - Udo Kragl
- Department of Chemistry, University of Rostock, Albert-Einstein-Straße
3a, D-18059 Rostock, Germany
- Faculty
of Interdisciplinary Research, University of Rostock, Wismarsche Straße 8, D-18057
Rostock, Germany
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19
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Weinberg DR, Gagliardi CJ, Hull JF, Murphy CF, Kent CA, Westlake BC, Paul A, Ess DH, McCafferty DG, Meyer TJ. Proton-Coupled Electron Transfer. Chem Rev 2012; 112:4016-93. [DOI: 10.1021/cr200177j] [Citation(s) in RCA: 1125] [Impact Index Per Article: 93.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- David R. Weinberg
- Department
of Chemistry, University
of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290,
United States
- Department of Physical and Environmental
Sciences, Colorado Mesa University, 1100 North Avenue, Grand Junction,
Colorado 81501-3122, United States
| | - Christopher J. Gagliardi
- Department
of Chemistry, University
of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290,
United States
| | - Jonathan F. Hull
- Department
of Chemistry, University
of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290,
United States
| | - Christine Fecenko Murphy
- Department
of Chemistry, B219
Levine Science Research Center, Box 90354, Duke University, Durham,
North Carolina 27708-0354, United States
| | - Caleb A. Kent
- Department
of Chemistry, University
of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290,
United States
| | - Brittany C. Westlake
- The American Chemical Society,
1155 Sixteenth Street NW, Washington, District of Columbia 20036,
United States
| | - Amit Paul
- Department
of Chemistry, University
of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290,
United States
| | - Daniel H. Ess
- Department
of Chemistry, University
of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290,
United States
| | - Dewey Granville McCafferty
- Department
of Chemistry, B219
Levine Science Research Center, Box 90354, Duke University, Durham,
North Carolina 27708-0354, United States
| | - Thomas J. Meyer
- Department
of Chemistry, University
of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290,
United States
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20
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Kao YT, Song QH, Saxena C, Wang L, Zhong D. Dynamics and mechanism of DNA repair in a biomimetic system: flavin-thymine dimer adduct. J Am Chem Soc 2012; 134:1501-3. [PMID: 22239341 DOI: 10.1021/ja2112788] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
To mimic photolyase for efficient repair of UV-damaged DNA, numerous biomimetic systems have been synthesized, but all show low repair efficiency. The molecular mechanism of this low-efficiency process is still poorly understood. Here we report our direct mapping of the repair processes of a flavin-thymine dimer adduct with femtosecond resolution. We followed the entire dynamic evolution and observed direct electron transfer (ET) from the excited flavin to the thymine dimer in 79 ps. We further observed two competitive pathways, productive dimer ring splitting within 435 ps and futile back-ET in 95 ps. Our observations reveal that the underlying mechanism for the low repair quantum yield of flavin-thymine dimer adducts is the short-lived excited flavin moiety and the fast dynamics of futile back-ET without repair.
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Affiliation(s)
- Ya-Ting Kao
- Department of Physics, and Program of Biophysics, The Ohio State University, Columbus, Ohio 43210, USA
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21
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Cannizzo A. Ultrafast UV spectroscopy: from a local to a global view of dynamical processes in macromolecules. Phys Chem Chem Phys 2012; 14:11205-23. [DOI: 10.1039/c2cp40567a] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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22
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Selby CP, Sancar A. The second chromophore in Drosophila photolyase/cryptochrome family photoreceptors. Biochemistry 2011; 51:167-71. [PMID: 22175817 DOI: 10.1021/bi201536w] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The photolyase/cryptochrome family of proteins are FAD-containing flavoproteins which carry out blue-light-dependent functions including DNA repair, plant growth and development, and regulation of the circadian clock. In addition to FAD, many members of the family contain a second chromophore which functions as a photo-antenna, harvesting light and transferring the excitation energy to FAD and thus increasing the efficiency of the system. The second chromophore is methenyltetrahydrofolate (MTHF) in most photolyases characterized to date and FAD, FMN, or 5-deazariboflavin in others. To date, no second chromophore has been identified in cryptochromes. Drosophila contains three members of the cryptochrome/photolyase family: cyclobutane pyrimidine dimer (CPD) photolyase, (6-4) photoproduct photolyase, and cryptochrome. We developed an expression system capable of incorporating all known second chromophores into the cognate cryptochrome/photolyase family members. Using this system, we demonstrate that Drosophila CPD photolyase and (6-4) photolyase employ 5-deazariboflavin as their second chromophore, but Drosophila cryptochrome, which is evolutionarily closer to (6-4) photolyase than the CPD photolyase, lacks a second chromophore.
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Affiliation(s)
- Christopher P Selby
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599-7260, United States
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23
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Pan Z, Chen J, Schreier WJ, Kohler B, Lewis FD. Thymine dimer photoreversal in purine-containing trinucleotides. J Phys Chem B 2011; 116:698-704. [PMID: 22103806 DOI: 10.1021/jp210575g] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Cyclobutane-pyrimidine dimer yields in UV-irradiated DNA are controlled by the equilibrium between forward and reverse photoreactions. Past studies have shown that dimer yields are suppressed at sites adjacent to a purine base, but the underlying causes are unclear. In order to investigate whether this suppression is the result of repair by electron transfer from a neighboring nucleobase, the yields and dynamics of the reverse reaction were studied using trinucleotides containing a cis-syn dimer (T<>T) flanked on the 5' or the 3' side by adenine or guanine. The probability of forming an excited state on T<>T or on the purine base was varied by tuning the irradiation wavelength between 240 and 280 nm. Cleavage quantum yields decrease by an order of magnitude over this wavelength range and are less than 1% at 280 nm, a wavelength that excites the purine base with more than 95% probability. Conditional quantum yields of cleavage for the trinucleotides given excitation of T<>T are similar in magnitude to the quantum yield of cleavage of unmodified T<>T. These results indicate that within experimental uncertainty all photoreversal in these single-stranded substrates is the result of direct electronic excitation of T<>T. Photolyase-like repair of T<>T due to electron transfer from an adjacent purine is negligible in these substrates. Instead, the observed variation in photoreversal quantum yields for adenine- versus guanine-flanked cis-syn dimer could be due to uncertainties in absorption cross sections or to a modest quenching effect by the purine on the excited state of T<>T. Pump-probe measurements reveal that the excited-state lifetimes of A or G in the dimer-containing trinucleotides are unperturbed by the neighboring dimer, indicating that electron transfer from purine base to T<>T is not competitive with rapid excited-state deactivation. Pump-probe measurements on unmodified T<>T in aqueous solution indicate that cleavage is most likely complete on a picosecond or subpicosecond time scale.
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Affiliation(s)
- Zhengzheng Pan
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
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24
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Dynamics and mechanism of cyclobutane pyrimidine dimer repair by DNA photolyase. Proc Natl Acad Sci U S A 2011; 108:14831-6. [PMID: 21804035 DOI: 10.1073/pnas.1110927108] [Citation(s) in RCA: 125] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Photolyase uses blue light to restore the major ultraviolet (UV)-induced DNA damage, the cyclobutane pyrimidine dimer (CPD), to two normal bases by splitting the cyclobutane ring. Our earlier studies showed that the overall repair is completed in 700 ps through a cyclic electron-transfer radical mechanism. However, the two fundamental processes, electron-tunneling pathways and cyclobutane ring splitting, were not resolved. Here, we use ultrafast UV absorption spectroscopy to show that the CPD splits in two sequential steps within 90 ps and the electron tunnels between the cofactor and substrate through a remarkable route with an intervening adenine. Site-directed mutagenesis reveals that the active-site residues are critical to achieving high repair efficiency, a unique electrostatic environment to optimize the redox potentials and local flexibility, and thus balance all catalytic reactions to maximize enzyme activity. These key findings reveal the complete spatio-temporal molecular picture of CPD repair by photolyase and elucidate the underlying molecular mechanism of the enzyme's high repair efficiency.
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25
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Dynamics and mechanism of repair of ultraviolet-induced (6-4) photoproduct by photolyase. Nature 2010; 466:887-890. [PMID: 20657578 PMCID: PMC3018752 DOI: 10.1038/nature09192] [Citation(s) in RCA: 165] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2010] [Revised: 08/12/2010] [Accepted: 05/20/2010] [Indexed: 01/02/2023]
Abstract
One of the detrimental effects of UV radiation on DNA is the formation of the (6-4) photoproduct (6-4PP) between two adjacent pyrimidines1. This lesion interferes with replication and transcription and may result in mutation and cell death2. In many organisms a flavoenzyme called photolyase uses blue light energy to repair the 6-4PP3. The molecular mechanism of the repair reaction is poorly understood. Here, we use ultrafast spectroscopy to show that the key step in the repair photocycle is a cyclic proton transfer between the enzyme and the substrate. By femtosecond synchronization of the enzymatic dynamics with the repair function, we followed the function evolution and observed direct electron transfer from the excited flavin cofactor to the 6-4PP in 225 ps but surprisingly fast back electron transfer in 50 ps without repair. Strikingly, we found that the catalytic proton transfer between a histidine residue in the active site and the 6-4PP, induced by the initial photoinduced electron transfer from the excited flavin cofactor to 6-4PP, occurs in 425 ps and leads to 6-4PP repair in tens of nanoseconds. These key dynamics define the repair photocycle and explain the underlying molecular mechanism of the enzyme’s modest efficiency.
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26
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Weber S, Biskup T, Okafuji A, Marino AR, Berthold T, Link G, Hitomi K, Getzoff ED, Schleicher E, Norris JR. Origin of light-induced spin-correlated radical pairs in cryptochrome. J Phys Chem B 2010; 114:14745-54. [PMID: 20684534 DOI: 10.1021/jp103401u] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Blue-light excitation of cryptochromes and homologues uniformly triggers electron transfer (ET) from the protein surface to the flavin adenine dinucleotide (FAD) cofactor. A cascade of three conserved tryptophan residues has been considered to be critically involved in this photoreaction. If the FAD is initially in its fully oxidized (diamagnetic) redox state, light-induced ET via the tryptophan triad generates a series of short-lived spin-correlated radical pairs comprising an FAD radical and a tryptophan radical. Coupled doublet-pair species of this type have been proposed as the basis, for example, of a biological magnetic compass in migratory birds, and were found critical for some cryptochrome functions in vivo. In this contribution, a cryptochrome-like protein (CRYD) derived from Xenopus laevis has been examined as a representative system. The terminal radical-pair state FAD(•)···W324(•) of X. laevis CRYD has been characterized in detail by time-resolved electron-paramagnetic resonance (TREPR) at X-band microwave frequency (9.68 GHz) and magnetic fields around 345 mT, and at Q-band (34.08 GHz) at around 1215 mT. Different precursor states, singlet versus triplet, of radical-pair formation have been considered in spectral simulations of the experimental electron-spin polarized TREPR signals. Conclusively, we present evidence for a singlet-state precursor of FAD(•)···W324(•) radical-pair generation because at both magnetic fields, where radical pairs were studied by TREPR, net-zero electron-spin polarization has been detected. Neither a spin-polarized triplet precursor nor a triplet at thermal equilibrium can explain such an electron-spin polarization. It turns out that a two-microwave-frequency TREPR approach is essential to draw conclusions on the nature of the precursor electronic states in light-induced spin-correlated radical pair formations.
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Affiliation(s)
- Stefan Weber
- Institute of Physical Chemistry, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany.
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27
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Rasmussen AM, Lind MC, Kim S, Schaefer HF. Hydration of the Lowest Triplet States of the DNA/RNA Pyrimidines. J Chem Theory Comput 2010; 6:930-9. [DOI: 10.1021/ct900478c] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Andrew M. Rasmussen
- Center for Computational Quantum Chemistry, University of Georgia, Athens, Georgia 30602
| | - Maria C. Lind
- Center for Computational Quantum Chemistry, University of Georgia, Athens, Georgia 30602
| | - Sunghwan Kim
- Center for Computational Quantum Chemistry, University of Georgia, Athens, Georgia 30602
| | - Henry F. Schaefer
- Center for Computational Quantum Chemistry, University of Georgia, Athens, Georgia 30602
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28
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Ultrafast solvation dynamics at binding and active sites of photolyases. Proc Natl Acad Sci U S A 2010; 107:2914-9. [PMID: 20133751 DOI: 10.1073/pnas.1000001107] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Dynamic solvation at binding and active sites is critical to protein recognition and enzyme catalysis. We report here the complete characterization of ultrafast solvation dynamics at the recognition site of photoantenna molecule and at the active site of cofactor/substrate in enzyme photolyase by examining femtosecond-resolved fluorescence dynamics and the entire emission spectra. With direct use of intrinsic antenna and cofactor chromophores, we observed the local environment relaxation on the time scales from a few picoseconds to nearly a nanosecond. Unlike conventional solvation where the Stokes shift is apparent, we observed obvious spectral shape changes with the minor, small, and large spectral shifts in three function sites. These emission profile changes directly reflect the modulation of chromophore's excited states by locally constrained protein and trapped-water collective motions. Such heterogeneous dynamics continuously tune local configurations to optimize photolyase's function through resonance energy transfer from the antenna to the cofactor for energy efficiency and then electron transfer between the cofactor and the substrate for repair of damaged DNA. Such unusual solvation and synergetic dynamics should be general in function sites of proteins.
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29
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Abstract
DNA polymerases (Pols) act as key players in DNA metabolism. These enzymes are the only biological macromolecules able to duplicate the genetic information stored in the DNA and are absolutely required every time this information has to be copied, as during DNA replication or during DNA repair, when lost or damaged DNA sequences have to be replaced with "original" or "correct" copies. In each DNA repair pathway one or more specific Pols are required. A feature of mammalian DNA repair pathways is their redundancy. The failure of one of these pathways can be compensated by another one. However, several DNA lesions require a specific repair pathway for error free repair. In many tumors one or more DNA repair pathways are affected, leading to error prone repair of some kind of lesions by alternatives routes, thus leading to accumulation of mutations and contributing to genomic instability, a common feature of cancer cell. In this chapter, we present the role of each Pol in genome maintenance and highlight the connections between the malfunctioning of these enzymes and cancer progress.
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Affiliation(s)
- Emmanuele Crespan
- Istituto di Genetica Molecolare IGM-CNR, Consiglio Nazionale delle Ricerche, I-27100 Pavia, Italy
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30
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Synthesis of Coenzyme Q10 and β-carotene by Yeasts Isolated from Antarctic Soil and Lichen in Response to Ultraviolet and Visible Radiations. Appl Biochem Biotechnol 2009; 162:795-804. [DOI: 10.1007/s12010-009-8845-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2009] [Accepted: 10/29/2009] [Indexed: 10/20/2022]
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31
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Hill SE, Bandaria JN, Fox M, Vanderah E, Kohen A, Cheatum CM. Exploring the molecular origins of protein dynamics in the active site of human carbonic anhydrase II. J Phys Chem B 2009; 113:11505-10. [PMID: 19637848 PMCID: PMC2736349 DOI: 10.1021/jp901321m] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We present three-pulse vibrational echo measurements of azide ion bound to the active site Zn of human carbonic anhydrase II (HCA II) and of two separate active-site mutants Thr199 --> Ala (T199A) and Leu198 --> Phe (L198F). Because structural motions of the protein active site influence the frequency of bound ligands, the differences in the time scales of the frequency-frequency correlation functions (FFCFs) obtained from global fits to each set of data allow us to make inferences about the time scales of the active site dynamics of HCA II. Surprisingly, the deletion of a potential electrostatic interaction in results in very little change in the FFCF, but the insertion of the bulky phenylalanine ring in causes much faster dynamics. We conclude that the fast, sub-picosecond time scale in the correlation function is attributable to hydrogen bond dynamics, and the slow, apparently static contribution is due to the conformational flexibility of Zn-bound azide in the active site.
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Affiliation(s)
- Sarah E Hill
- Department of Chemistry and Optical Science and Technology Center, University of Iowa, Iowa City, Iowa 52242, USA.
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32
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Zhong D. Hydration Dynamics and Coupled Water-Protein Fluctuations Probed by Intrinsic Tryptophan. ADVANCES IN CHEMICAL PHYSICS 2009. [DOI: 10.1002/9780470508602.ch3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
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33
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Usman A, Brazard J, Martin MM, Plaza P, Heijde M, Zabulon G, Bowler C. Spectroscopic characterization of a (6-4) photolyase from the green alga Ostreococcus tauri. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2009; 96:38-48. [PMID: 19427226 DOI: 10.1016/j.jphotobiol.2009.04.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2008] [Revised: 03/10/2009] [Accepted: 04/06/2009] [Indexed: 10/20/2022]
Abstract
The cofactor content of OtCPF1, a (6-4) photolyase isolated from the green marine alga Ostreococcus tauri, was characterized by steady-state absorption and fluorescence spectroscopy. The heterologously expressed, GST-fused, purified protein (MW: 89kDa) is non-covalently bound to flavin adenine dinucleotide (FAD), with a flavin to apoprotein molecular ratio of 64%. No light-harvesting chromophore was found in this protein. In freshly purified OtCPF1, FAD is present in three different redox states: the fully oxidized form (FAD(ox), 82%), the neutral semiquinone (FADH*, 14%) and the fully reduced anion (FADH-, 4%). Keeping the sample in the dark, at 5 degrees C, yields oxidation of FADH* and FADH-, partial release of FAD to the solution and slow degradation of the protein. Upon steady-state blue-light irradiation of OtCPF1 at 450nm, photoreduction processes leading to an accumulation of stable FADH* and FADH- species are observed. We demonstrate that this accumulation is due to the presence of an external electron donor agent in the purification buffer. Composition changes observed under steady-state photoexcitation are interpreted in terms of photoinduced reductions of FAD(ox) and FADH* states and competitive back reactions. Specific irradiation by red light at 620 nm shows both photoreduction of FADH* to FADH- and irreversible oxidation of FADH* to FAD(ox). The photoinduced oxidation reaction is believed to be indirectly caused by the external donor agent present in the buffer. Photoexcitation is also shown to stabilize the binding of FAD to the protein. We suggest this effect to be due to slight changes in the protein conformation, possibly strengthening the hydrogen-bonding network surrounding FAD.
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Affiliation(s)
- Anwar Usman
- UMR 8640 CNRS-ENS-UPMC, Département de Chimie, Ecole Normale Supérieure, 24 rue Lhomond, Paris, France
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34
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Kao YT, Tan C, Song SH, Öztürk N, Li J, Wang L, Sancar A, Zhong D. Ultrafast dynamics and anionic active states of the flavin cofactor in cryptochrome and photolyase. J Am Chem Soc 2008; 130:7695-701. [PMID: 18500802 PMCID: PMC2661107 DOI: 10.1021/ja801152h] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report here our systematic studies of the dynamics of four redox states of the flavin cofactor in both photolyases and insect type 1 cryptochromes. With femtosecond resolution, we observed ultrafast photoreduction of oxidized state flavin adenine dinucleotide (FAD) in subpicosecond and of neutral radical semiquinone (FADH(*)) in tens of picoseconds through intraprotein electron transfer mainly with a neighboring conserved tryptophan triad. Such ultrafast dynamics make these forms of flavin unlikely to be the functional states of the photolyase/cryptochrome family. In contrast, we find that upon excitation the anionic semiquinone (FAD(*-)) and hydroquinone (FADH(-)) have longer lifetimes that are compatible with high-efficiency intermolecular electron transfer reactions. In photolyases, the excited active state (FADH(-)*) has a long (nanosecond) lifetime optimal for DNA-repair function. In insect type 1 cryptochromes known to be blue-light photoreceptors the excited active form (FAD(*-)*) has complex deactivation dynamics on the time scale from a few to hundreds of picoseconds, which is believed to occur through conical intersection(s) with a flexible bending motion to modulate the functional channel. These unique properties of anionic flavins suggest a universal mechanism of electron transfer for the initial functional steps of the photolyase/cryptochrome blue-light photoreceptor family.
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Affiliation(s)
- Ya-Ting Kao
- Departments of Physics, Chemistry, and Biochemistry, Programs of Biophysics, Chemical Physics, and Biochemistry, The Ohio State University, 191 West Woodruff Avenue, Columbus, Ohio, 43210
| | - Chuang Tan
- Departments of Physics, Chemistry, and Biochemistry, Programs of Biophysics, Chemical Physics, and Biochemistry, The Ohio State University, 191 West Woodruff Avenue, Columbus, Ohio, 43210
| | - Sang-Hun Song
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Mary Ellen Jones Building, CB 7260, Chapel Hill, NC 27599
| | - Nuri Öztürk
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Mary Ellen Jones Building, CB 7260, Chapel Hill, NC 27599
| | - Jiang Li
- Departments of Physics, Chemistry, and Biochemistry, Programs of Biophysics, Chemical Physics, and Biochemistry, The Ohio State University, 191 West Woodruff Avenue, Columbus, Ohio, 43210
| | - Lijuan Wang
- Departments of Physics, Chemistry, and Biochemistry, Programs of Biophysics, Chemical Physics, and Biochemistry, The Ohio State University, 191 West Woodruff Avenue, Columbus, Ohio, 43210
| | - Aziz Sancar
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Mary Ellen Jones Building, CB 7260, Chapel Hill, NC 27599
| | - Dongping Zhong
- Departments of Physics, Chemistry, and Biochemistry, Programs of Biophysics, Chemical Physics, and Biochemistry, The Ohio State University, 191 West Woodruff Avenue, Columbus, Ohio, 43210
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35
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Öztürk N, Song SH, Selby CP, Sancar A. Animal type 1 cryptochromes. Analysis of the redox state of the flavin cofactor by site-directed mutagenesis. J Biol Chem 2007; 283:3256-3263. [PMID: 18056988 DOI: 10.1074/jbc.m708612200] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
It has recently been realized that animal cryptochromes (CRYs) fall into two broad groups. Type 1 CRYs, the prototype of which is the Drosophila CRY, that is known to be a circadian photoreceptor. Type 2 CRYs, the prototypes of which are human CRY 1 and CRY 2, are known to function as core clock proteins. The mechanism of photosignaling by the Type 1 CRYs is not well understood. We recently reported that the flavin cofactor of the Type 1 CRY of the monarch butterfly may be in the form of flavin anion radical, FAD(*-), in vivo. Here we describe the purification and characterization of wild-type and mutant forms of Type 1 CRYs from fruit fly, butterfly, mosquito, and silk moth. Cryptochromes from all four sources contain FAD(ox) when purified, and the flavin is readily reduced to FAD(*-) by light. Interestingly, mutations that block photoreduction in vitro do not affect the photoreceptor activities of these CRYs, but mutations that reduce the stability of FAD(*-) in vitro abolish the photoreceptor function of Type 1 CRYs in vivo. Collectively, our data provide strong evidence for functional similarities of Type 1 CRYs across insect species and further support the proposal that FAD(*-) represents the ground state and not the excited state of the flavin cofactor in Type 1 CRYs.
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Affiliation(s)
- Nuri Öztürk
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599
| | - Sang-Hun Song
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599
| | - Christopher P Selby
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599
| | - Aziz Sancar
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599.
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36
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Affiliation(s)
- My Hang V Huynh
- DE-1: High Explosive Science and Technology Group, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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