TY - JOUR A1 - Miyazaki, Mitsuhiko A1 - Kamiya, Tairiku A1 - Wohlgemuth, Matthias A1 - Chatterjee, Kuntal A1 - Mitrić, Roland A1 - Dopfer, Otto A1 - Fujii, Masaaki T1 - Real-time observation of photoionization-induced water migration dynamics in 4-methylformanilide–water by picosecond time-resolved infrared spectroscopy and ab initio molecular dynamics simulations JF - Physical Chemistry Chemical Physics N2 - A novel time-resolved pump–probe spectroscopic approach that enables to keep high resolution in both the time and energy domain, nanosecond excitation–picosecond ionization–picosecond infrared probe (ns–ps–ps TRIR) spectroscopy, has been applied to the trans-4-methylformanilide–water (4MetFA–W) cluster. Water migration dynamics from the CO to the NH binding site in a peptide linkage triggered by photoionization of 4MetFA–W is directly monitored by the ps time evolution of IR spectra, and the presence of an intermediate state is revealed. The time evolution is analyzed by rate equations based on a four-state model of the migration dynamics. Time constants for the initial to the intermediate and hot product and to the final product are obtained. The acceleration of the dynamics by methyl substitution and the strong contribution of intracluster vibrational energy redistribution in the termination of the solvation dynamics is suggested. This picture is well confirmed by the ab initio on-the-fly molecular dynamics simulations. Vibrational assignments of 4MetFA and 4MetFA–W in the neutral (S0 and S1) and ionic (D0) electronic states measured by ns IR dip and electron-impact IR photodissociation spectroscopy are also discussed prior to the results of time-resolved spectroscopy. Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-370868 VL - 24 ER - TY - JOUR A1 - Wohlgemuth, Matthias A1 - Miyazaki, Mitsuhiko A1 - Tsukada, Kohei A1 - Weiler, Martin A1 - Dopfer, Otto A1 - Fujii, Masaaki A1 - Mitrić, Roland T1 - Deciphering environment effects in peptide bond solvation dynamics by experiment and theory JF - Physical Chemistry Chemical Physics N2 - Most proteins work in aqueous solution and the interaction with water strongly affects their structure and function. However, experimentally the motion of a specific single water molecule is difficult to trace by conventional methods, because they average over the heterogeneous solvation structure of bulk water surrounding the protein. Here, we provide a detailed atomistic picture of the water rearrangement dynamics around the –CONH– peptide linkage in the two model systems formanilide and acetanilide, which simply differ by the presence of a methyl group at the peptide linkage. The combination of picosecond pump–probe time-resolved infrared spectroscopy and molecular dynamics simulations demonstrates that the solvation dynamics at the molecular level is strongly influenced by this small structural difference. The effective timescales for solvent migration triggered by ionization are mainly controlled by the efficiency of the kinetic energy redistribution rather than the shape of the potential energy surface. This approach provides a fundamental understanding of protein hydration and may help to design functional molecules in solution with tailored properties. KW - infrared-spectra KW - hydration dynamics KW - trans-formanilide KW - water migration KW - protein hydration Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-159647 UR - http://pubs.rsc.org/en/content/articlelanding/2017/cp/c7cp03992a N1 - Accepted Version VL - 19 IS - 33 ER - TY - INPR A1 - Wohlgemuth, Matthias A1 - Miyazaki, Mitsuhiko A1 - Tsukada, Kohei A1 - Weiler, Martin A1 - Dopfer, Otto A1 - Fujii, Masaaki A1 - Mitrić, Roland T1 - Deciphering environment effects in peptide bond solvation dynamics by experiment and theory T2 - Physical Chemistry Chemical Physics N2 - Most proteins work in aqueous solution and the interaction with water strongly affects their structure and function. However, experimentally the motion of a specific single water molecule is difficult to trace by conventional methods, because they average over the heterogeneous solvation structure of bulk water surrounding the protein. Here, we provide a detailed atomistic picture of the water rearrangement dynamics around the –CONH– peptide linkage in the two model systems formanilide and acetanilide, which simply differ by the presence of a methyl group at the peptide linkage. The combination of picosecond pump–probe time-resolved infrared spectroscopy and molecular dynamics simulations demonstrates that the solvation dynamics at the molecular level is strongly influenced by this small structural difference. The effective timescales for solvent migration triggered by ionization are mainly controlled by the efficiency of the kinetic energy redistribution rather than the shape of the potential energy surface. This approach provides a fundamental understanding of protein hydration and may help to design functional molecules in solution with tailored properties. KW - hydration dynamics KW - trans-formanilide KW - water migration KW - protein hydration KW - infrared-spectra Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-159483 UR - http://pubs.rsc.org/en/content/articlelanding/2017/cp/c7cp03992a N1 - Submitted version ER -