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- Ai, Yue-Jie, 1982-, et al.
(författare)
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Repair of DNA Dewar Photoproduct to (6-4) photoproduct in (6-4) Photolyase
- 2011
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Ingår i: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-6106 .- 1520-5207. ; 115:37, s. 10976-10982
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Tidskriftsartikel (refereegranskat)abstract
- Dewar photoproduct (Dewar PP) is the valence isomer of (6-4) photoproduct ((6-4)PP) in photodamaged DNA. Compared to the extensive studied CPD photoproducts, the underlying repair mechanisms for the (6-4)PP, and especially for the Dewar PP, are not well-established to date. In this paper, the repair mechanism of DNA Dewar photoproduct T(dew)C in (6-4) photolyase was elucidated using hybrid density functional theory. Our results showed that, during the repair process, the T(dew)C has to isomerize to T(6-4)C photolesion first via direct C6'-N3' bond cleavage facilitated by electron injection. This isomerization mechanism is energetically much more efficient than other possible rearrangement pathways. The calculations provide a theoretical interpretation to recent experimental observations.
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| 4. |
- Ai, Yue-Jie, et al.
(författare)
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Role of non-Condon vibronic coupling and conformation change on two-photon absorption spectra of green fluorescent protein
- 2013
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Ingår i: Molecular Physics. - : Informa UK Limited. - 0026-8976 .- 1362-3028. ; 111:9-11, s. 1316-1321
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Tidskriftsartikel (refereegranskat)abstract
- Two-photon absorption spectra of green fluorescent proteins (GFPs) often show a blue-shift band compared to their conventional one-photon absorption spectra, which is an intriguing feature that has not been well understood. We present here a systematic study on one- and two-photon spectra of GFP chromophore by means of the density functional response theory and complete active space self-consistent field (CASSCF) methods. It shows that the popular density functional fails to provide correct vibrational progression for the spectra. The non-Condon vibronic coupling, through the localised intrinsic vibrational modes of the chromophore, is responsible for the blue-shift in the TPA spectra. The cis to trans isomerisation can be identified in high-resolution TPA spectra. Our calculations demonstrate that the high level ab initio multiconfigurational CASSCF method, rather than the conventional density functional theory is required for investigating the essential excited-state properties of the GFP chromophore.
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- Ai, Yue-Jie, et al.
(författare)
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Theoretical Studies on Photoisomerizations of (6-4) and Dewar Photolesions in DNA
- 2010
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Ingår i: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-6106 .- 1520-5207. ; 114:44, s. 14096-14102
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Tidskriftsartikel (refereegranskat)abstract
- The (6-4) photoproduct ((6-4) PP) is one of the main lesions in UV-induced DNA damage. The (6-4) PP and its valence isomer Dewar photoproduct (Dewar PP) can have a great threat of mutation and cancer but gained much less attention to date. In this study, with density functional theory (DFT) and the complete active space self-consistent field (CASSCF) methods, the photoisomerization processes between the (6-4) PP and the Dewar PP in the gas phase, the aqueous solution, and the photolyase have been carefully examined. Noticeably, the solvent effect is treated with the CASPT2//CASSCF/Amber (QM/MM) method. Our calculations show that the conical intersection (Cl) points play a crucial role in the photoisomerization reaction between the (6-4) PP and the Dewar PP in the gas and the aqueous solution. The ultrafast internal conversion between the S-2 ((1)pi pi*) and the So states via a distorted intersection point is found to be responsible for the formation of the Dewar PP lesion at 313 nm, as observed experimentally. For the reversed isomeric process, two channels involving the "dark" excited states have been identified. In addition to the above passages, in the photolyase, a new electron-injection isomerization process as an efficient way for the photorepair of the Dewar PP is revealed.
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- Ai, Yue-Jie, et al.
(författare)
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Theoretical studies on the isomerization mechanism of the ortho-green fluorescent protein chromophore
- 2012
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Ingår i: Physical Chemistry, Chemical Physics - PCCP. - : Royal Society of Chemistry (RSC). - 1463-9076 .- 1463-9084. ; 14:38, s. 13409-13414
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Tidskriftsartikel (refereegranskat)abstract
- We present a systematic theoretical investigation on the overall ground state and excited-state isomerization reaction mechanism of ortho-green fluorescent protein chromophore (o-HBDI) using the density functional theory and the multireference methods. The calculated results and subsequent analysis suggest the possible isomerization mechanism for o-HBDI. By comparison with experimental observation and detailed analysis, it is concluded that as initiated by the excited-state intramolecular proton transfer reaction, the conical intersection between the ground state and the excited state along the C4-C5 single-bond rotational coordinate is responsible for the rapid deactivation of o-HBDI.
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- Ai, Yue-Jie, et al.
(författare)
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Ultrafast deactivation processes in the 2-aminopyridine dimer and the adenine-thymine base pair : Similarities and differences
- 2010
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Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 133:6, s. 064302-
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Tidskriftsartikel (refereegranskat)abstract
- 2-aminopyridine dimer has frequently been used as a model system for studying photochemistry of DNA base pairs. We examine here the relevance of 2-aminopyridine dimer for a Watson-Crick adenine-thymine base pair by studying UV-light induced photodynamics along two main hydrogen bridges after the excitation to the localized (1)pi pi(*) excited-state. The respective two-dimensional potential-energy surfaces have been determined by time-dependent density functional theory with Coulomb-attenuated hybrid exchange-correlation functional (CAM-B3LYP). Different mechanistic aspects of the deactivation pathway have been analyzed and compared in detail for both systems, while the related reaction rates have also be obtained from Monte Carlo kinetic simulations. The limitations of the 2-aminopyridine dimer as a model system for the adenine-thymine base pair are discussed. (C) 2010 American Institute of Physics. [doi:10.1063/1.3464485]
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- Duan, Sai, et al.
(författare)
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Roles of Plasmonic Excitation and Protonation on Photoreactions of p-Aminobenzenethiol on Ag Nanoparticles
- 2014
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Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 118:13, s. 6893-6902
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Tidskriftsartikel (refereegranskat)abstract
- There is increasing evidence that surface plasmons could catalyze photochemical reactions of organic molecules on metal surfaces. However, due to the complex interactions among the substrate, the adsorbate, the environment, and the incident light, the existence and the underlying mechanism of such catalytic processes have been under intense debate. Here we present a systematic first principles study on one of the most studied and controversial systems, namely, p-aminobenzenethiol (PATP) adsorbed on silver nanoparticles. Our calculations have confirmed that the observed surface-enhanced Raman scattering (SERS) bands at 1142, 1391, and 1440 cm(-1) of PATP on silver surfaces belong to its coupling reaction product, 4,4'-dimercaptoazobenzene (DMAB). It is found that the deprotonation or protonation of N atoms is the key initial step for the transformations between PATP and DMAB. The photodecomposition reaction from DMAB to PATP can occur only under the conditions that both proton transfer and plasmonic excitations have taken place. Moreover, in addition to the widely suggested hot-electron injection mechanism of plasmon, a new photochemical channel has been revealed in the decomposition of DMAB molecules under suitable incident light. This may open up an entire new type of chemical reaction in surface chemistry that we call plasmonic photochemistry. Our theoretical calculations provide consistent interpretations for the experimentally observed pH-,wavelength-,and electrode potential dependence of the SERS spectra of PATP/DMAB adsorbed on silver surfaces. Our findings highlight the important role of theoretical investigations for better understanding of complex processes involved in photochemical reaction of surface adsorbates.
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| 9. |
- Feng, Hongliang, et al.
(författare)
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Association between accelerometer-measured amplitude of rest-activity rhythm and future health risk : a prospective cohort study of the UK Biobank
- 2023
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Ingår i: The Lancet Healthy Longevity. - 2666-7568. ; 4:5, s. e200-e210
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The health effects of rest-activity rhythm are of major interest to public health, but its associations with health outcomes remain elusive. We aimed to examine the associations between accelerometer-measured rest-activity rhythm amplitude and health risks among the general UK population.METHODS: We did a prospective cohort analysis of UK Biobank participants aged 43-79 years with valid wrist-worn accelerometer data. Low rest-activity rhythm amplitude was defined as the first quintile of relative amplitude; all other quintiles were classified as high rest-activity rhythm amplitude. Outcomes of interest were defined using International Classification of Diseases 10th Revision codes and consisted of incident cancer and cardiovascular, infectious, respiratory, and digestive diseases, and all-cause and disease-specific (cardiovascular, cancer, and respiratory) mortality. Participants with a current diagnosis of any outcome of interest were excluded. We assessed the associations between decreased rest-activity rhythm amplitude and outcomes using Cox proportional hazards models.FINDINGS: Between June 1, 2013, and Dec 23, 2015, 103 682 participants with available raw accelerometer data were enrolled. 92 614 participants (52 219 [56·4%] women and 40 395 [42·6%] men) with a median age of 64 years (IQR 56-69) were recruited. Median follow-up was 6·4 years (IQR 5·8-6·9). Decreased rest-activity rhythm amplitude was significantly associated with increased incidence of cardiovascular diseases (adjusted hazard ratio 1·11 [95% CI 1·05-1·16]), cancer (1·08 [1·01-1·16]), infectious diseases (1·31 [1·22-1·41]), respiratory diseases (1·26 [1·19-1·34]), and digestive diseases (1·08 [1·03-1·14]), as well as all-cause mortality (1·54 [1·40-1·70]) and disease-specific mortality (1·73 [1·34-2·22] for cardiovascular diseases, 1·32 [1·13-1·55] for cancer, and 1·62 [1·25-2·09] for respiratory diseases). Most of these associations were not modified by age older than 65 years or sex. Among 16 accelerometer-measured rest-activity parameters, low rest-activity rhythm amplitude had the strongest or second- strongest associations with nine health outcomes.INTERPRETATION: Our results suggest that low rest-activity rhythm amplitude might contribute to major health outcomes and provide further evidence to promote risk-modifying strategies associated with rest-activity rhythm to improve health and longevity.
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