Investigating the impact of microhydration on the excited-states and electronic excitation properties of biomolecules has remained one of the important yet challenging aspects of science because of the complexity of developing models. However, with the advent of computational chemistry methods such as TD-DFT, many useful insights about the electronic excitation energy and excited-state nature of biomolecules can be explored. Accordingly, in our study, we have incorporated the TD-DFT/wB97XD/cc-pVTZ method to study the excited state properties of N-acetyl phenylalanine amide (NAPA-A(H2O) n) (n = 1 to 4) clusters from ground to the tenth lowest gaseous singlet excited state. We found that the C=O bond length gradually increases both in N-terminal amide and C-terminal amide after the sequential addition of water molecules because of intermolecular H-bonding and this intermolecular H-bonding becomes weaker after the sequential addition of H2O molecules. The UV absorption maxima of NAPA-A (H2O)n (n = 1 - 4) clusters consisted of two peaks that are S5←S0 (1st absorption) and S6←S0 (2nd absorption) excitations. The first absorption maxima were blue-shifted with the increase in oscillator strength. This means that strong H-bonds reduce the charge transfer and make clusters more rigid. On the other hand, the second absorption maxima were red-shifted with the decrease in oscillator strength. In the ECD spectra, the negative bands indicate the presence of an amide bond and L-configuration of micro hydrated NAPA-A clusters. Finally, our calculated absorption and fluorescence energy confirm that all the NAPA-A (H2O) n (n = 0 - 4) clusters revert to the ground state from the fluorescent state by emitting around 5.490 eV of light.
References
[1]
Level, M., Very, T., Gloaguen, E., Tardivel, B., Mons, M. and Brenner, V. (2022) Excited States Computation of Models of Phenylalanine Protein Chains: TD-DFT and Composite CC2/TD-DFT Protocols. International Journal of Molecular Sciences, 23, Article No. 621. https://doi.org/10.3390/ijms23020621
[2]
Stephens, A.D., Qaisrani, M.N., Ruggiero, M.T., Mirónf, G.D., Morzan, U.N., Lebrero, M.C.G., Jones, S.T.E., Poli, E., Bond, A.D., Woodhams, P.J., Kleist, E.M., Grisanti, L., Gebauer, R., Zeitler, J.A., Credgington, D., Hasanali, A. and Schierle, G.S.K. (2021) Short Hydrogen Bonds Enhance Nonaromatic Protein-Related Fluorescence. Proceedings of the National Academy of Sciences, 118, e2020389118. https://doi.org/10.1073/pnas.2020389118
[3]
Kerdpol, K., Daengngern, R., Sattayanon, C., Namuangruk, S., Rungrotmongkol, T., Wolschann, P., Kungwan, N. and Hannongbua, P. (2021) Effect of Water Microsolvation on the Excited-State Proton Transfer of 3-Hydroxyflavone Enclosed in γ-Cyclodextrin. Molecules, 26, Article No. 843. https://doi.org/10.3390/molecules26040843
[4]
Nagornova, N.S., Rizzo, T.R. and Boyarkin, O.V. (2012) Interplay of Intra- and Intermolecular H-Bonding in a Progressively Solvated Macrocyclic Peptide. Science, 336, 320-323. https://doi.org/10.1126/science.1218709
[5]
Barron, L.D. (2015) The Development of Biomolecular Raman Optical Activity Spectroscopy. Biomedical Spectroscopy and Imaging, 4, 223-253. https://doi.org/10.3233/BSI-150113
[6]
Biedermannová, L. and Schneider, B. (2016) Hydration of Proteins and Nucleic Acids: Advances in Experiment and Theory. A Review. Biochimica et Biophysica Acta (BBA)-General Subjects, 1860, 1821-1835. https://doi.org/10.1016/j.bbagen.2016.05.036
[7]
Cheng, C.-L. and Zhao, G.-J. (2012) Steered Molecular Dynamics Simulation Study on Dynamic Self-Assembly of Single-Stranded DNA with Double-Walled Carbon Nanotube and Graphene. Nanoscale, 4, 2301-2305. https://doi.org/10.1039/c2nr12112c
[8]
Cheng, C.-L., Zhang, M.-Z. and Zhao, G.-J. (2014) Mechanical Stability and Thermal Conductivity of β-Barrel in Green Fluorescent Protein by Steered Molecular Dynamics. RSC Advances, 4, 6513-6516. https://doi.org/10.1039/c3ra42679c
[9]
Zhang, M.-X., Chai, S. and Zhao, G.-J. (2012) BODIPY Derivatives as n-Type Organic Semiconductors: Isomer Effect on Carrier Mobility. Organic Electronics, 13, 215-221. https://doi.org/10.1016/j.orgel.2011.10.015
[10]
Li, H., Liu, Y., Yang, Y., Yang, D. and Sun, J. (2014) Excited-State Intramolecular Hydrogen Bonding of Compounds Based on 2-(2-Hydroxyphenyl)-1,3-benzoxazole in Solution: A TDDFT Study. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 133, 818-824. https://doi.org/10.1016/j.saa.2014.06.072
[11]
Liu, X., Yin, H., Li, H. and Shi, Y. (2017) Altering Intra- to Inter-Molecular Hydrogen Bonding by Dimethylsulfoxide: A TDDFT Study of Charge Transfer for Coumarin 343. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 177, 1-5. https://doi.org/10.1016/j.saa.2017.01.022
[12]
Wang, P., Song, X., Zhao, Z., Liu, L., Mu, W. and Hao, C. (2016) Role of the Electronic Excited-State Hydrogen Bonding in the Nitro-Explosives Detection by [Zn2(oba)2(bpy)]. Chemical Physics Letters, 661, 257-262. https://doi.org/10.1016/j.cplett.2016.06.085
[13]
Ji, M., Hao, C., Wang, D., Li, H. and Qiu, J. (2013) A Time-Dependent Density Functional Theory Study on the Effect of Electronic Excited-State Hydrogen Bonding on Luminescent MOFs. Dalton Transactions, 42, 3464-3470. https://doi.org/10.1039/C2DT32575F
[14]
Li, H., Liu, Y., Yang, Y., Yang, D. and Sun, J. (2014) Influences of Hydrogen Bonding Dynamics on Adsorption of Ethyl Mercaptan onto Functionalized Activated Carbons: A DFT/TDDFT Study. Journal of Photochemistry and Photobiology A: Chemistry, 291, 9-15. https://doi.org/10.1016/j.jphotochem.2014.06.017
[15]
Li, H., Yang, Y., Yang, D., Liu, Y. and Sun, J. (2014) TDDFT Study on the Excited State Hydrogen Bonding of N-(2-hydroxyethyl)-1,8-naphthalimide and N-(3- hydroxy-ethyl)-1,8-naphthalimide in Methanol Solution. Journal of Physical Organic Chemistry, 27, 170-176. https://doi.org/10.1002/poc.3255
[16]
Wei, N., Hamza, A., Hao, C., Xiu, Z. and Qiu, J. (2013) Time-Dependent Density Functional Theory Study on Hydrogen and Dihydrogen Bonding in Electronically Excited State of 2-Pyridone-Borane-Trimethylamine Cluster. Journal of Cluster Science, 24, 459-470. https://doi.org/10.1007/s10876-013-0572-5
[17]
Yang, D., Zheng, R. and Lv, J. (2017) Hydrogen Bonding and Excited State Properties of the Photoexcited Hydrogen-Bonded (E)-S-(2-aminopropyl) 3-(4-hydroxy-phenyl)prop-2-enethioate Complexes. Journal of Physical Organic Chemistry, 30, e3634. https://doi.org/10.1002/poc.3634
[18]
Mališ, M., Loquais, Y., Gloaguen, E., Jouvet, C., Brenner, V., Mons, M., Ljubić, I. and Došlić, N. (2014) Non-Radiative Relaxation of UV Photoexcited Phenylalanine Residues: Probing the Role of Conical Intersections by Chemical Substitution. Physical Chemistry Chemical Physics, 16, 2285-2288. https://doi.org/10.1039/c3cp53953a
[19]
Mališ, M. and Došlić, N. (2017) Nonradiative Relaxation Mechanisms of UV Excited Phenylalanine Residues: A Comparative Computational Study. Molecules, 22, Article No. 493. https://doi.org/10.3390/molecules22030493
[20]
Biswal, H.S., Loquais, Y., Tardivel, B., Gloaguen, E. and Mons, M. (2011) Isolated Monohydrates of a Model Peptide Chain: Effect of a First Water Molecule on the Secondary Structure of a Capped Phenylalanine. Journal of the American Chemical Society, 133, 3931-3942. https://doi.org/10.1021/ja108643p
Kumar, A., Toal, S.E., DiGuiseppi, D., Schweitzer-Stenner, R. and Wong, B.M. (2020) Water-Mediated Electronic Structure of Oligopeptides Probed by Their UV Circular Dichroism, Absorption Spectra, and Time-Dependent DFT Calculations. The Journal of Physical Chemistry B, 124, 2579-2590. https://doi.org/10.1021/acs.jpcb.0c00657
[23]
O’boyle, N.M., Tenderholt, A.L. and Langner, K.M. (2008) Cclib: A Library for Package Independent Computational Chemistry Algorithms. Journal of Computational Chemistry, 29, 839-845. https://doi.org/10.1002/jcc.20823
[24]
Alauddin, M. and Ripa, J.D. (2022) Effect of Microhydration on the Peptide Backbone of N-Acetyl-Phenylalaninylamide (NAPA) Using IR, Raman and Vibrational Chiroptical Spectrosocpies (VCD, ROA): A Computational Study. European Journal of Applied Sciences, 10, 617-638. https://doi.org/10.14738/aivp.104.12859
[25]
Hubbard, R.E. and Haider, M.K. (2010) Hydrogen Bonds in Proteins: Role and Strength. Encyclopedia of Life Sciences. John Wiley & Sons, Ltd., Hoboken. https://www.els.net https://doi.org/10.1002/9780470015902.a0003011.pub2
[26]
Micsonai, A., Bulyáki, É. and Kardos, J. (2021) BeStSel: From Secondary Structure Analysis to Protein Fold Prediction by Circular Dichroism Spectroscopy. In: Chen, Y.W. and Yiu, C.-P.B., Eds., Structural Genomics: General Applications, Vol. 2199, Springer, Berlin, 175-189. https://doi.org/10.1007/978-1-0716-0892-0_11
[27]
Lan, S.C. and Liu, Y.H. (2015) TDDFT Study on the Excited-State Proton Transfer of 8-Hydroxyquinoline: Key Role of the Excited-State Hydrogen-Bond Strengthening. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 139, 49-53. https://doi.org/10.1016/j.saa.2014.12.015
[28]
Zhao, G.J. and Han, K.L. (2007) Ultrafast Hydrogen Bond Strengthening of the Photoexcited Fluorenone in Alcohols for Facilitating the Fluorescence Quenching. The Journal of Physical Chemistry A, 111, 9218-9223. https://doi.org/10.1021/jp0719659
