title: Vibrational dynamics of deoxyguanosine 5'-monophosphate following UV excitation.
abstract: The relaxation dynamics of the DNA nucleotide deoxyguanosine 5'-monophosphate (dGMP) following 266 nm photoexcitation has been studied by transient IR spectroscopy with femtosecond time resolution. The induced dynamics of the amide I (carbonyl) stretch, the asymmetric guanine ring stretch and the phosphate asymmetric stretch are monitored in the region 1000-1800 cm(-1). Excitation and subsequent rapid internal conversion to a "hot" ground state is reflected by depletion of the vibrational ground states of the amide I stretch and guanine ring stretch. However, the vibrational ground state of the phosphate is left unperturbed, indicating the absence of vibrational coupling between the guanine ring system and the phosphate group. The vibrational ground state of the amide I is repopulated in 2.5 ps (±0.2 ps) while it takes 3.7 ps (±0.5 ps) to repopulate the guanine ring vibration. This article discusses two possible relaxation pathways of dGMP, as well as the implications of the weak phosphate dynamics.
authors: Department of Chemistry, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark. jbn@chem.au.dk
authors: Jakob Brun
authors: JB
authors: Nielsen
authors: Jan
authors: J
authors: Thøgersen
authors: Svend Knak
authors: SK
authors: Jensen
authors: Steen Brøndsted
authors: SB
authors: Nielsen
authors: Søren Rud
authors: SR
authors: Keiding
mesh_terms: D003848:Deoxyguanine Nucleotides / Q000737:chemistry*; D011789:Quantum Theory; D013055:Spectrophotometry, Infrared; D014466:Ultraviolet Rays; D014732:Vibration
chemical_list: D003848:Deoxyguanine Nucleotides; C007257:2'-deoxyguanosine 5'-phosphate