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  • 03월 02일 17시 이후 : 초록수정 불가능, 일정확인 및 검색만 가능

제117회 대한화학회 학술발표회, 총회 및 기기전시회 안내 Existence of planar state and role of solvation for the excited state dynamics of Thioflavin T

2016년 2월 18일 16시 44분 03초
PHYS.O-8 이곳을 클릭하시면 발표코드에 대한 설명을 보실 수 있습니다.
목 10시 : 30분
물리화학 - 일반 구두발표 (General Oral Presentation)
저자 및
김준우, 주태하*
포항공과대학교(POSTECH) 화학과, Korea
Amyloid fibrillation has been widely studied since it is known to be related to many amyloid diseases such as Alzheimer’s, Parkinson’s, and Type II diabetes. Thioflavin-T (ThT) is a molecular probe that monitors the fibrillation process; its fluorescence quantum yield dramatically increases when it is adsorbed on fibril structure. ThT consists of a thiazole group and a dimethyl aniline group connected by a single C-C bond. Previous researches claimed that restriction of the twisting between the two groups is the origin of the fluorescence enhancement. We have discovered through time-resolved studies and quantum mechanical calculations that the excited state dynamics of ThT cannot be described by the simple twisting, and the dynamics is strongly influenced by the solvation dynamics. The excited ThT initially forms a metastable planar state, and a charge transfer (CT) reaction takes place, which is driven by the solvation dynamics. Agreement between the vibrational spectrum obtained by transient absorption with 20 fs time-resolution and the Huang-Rhys factor spectrum calculated by time-dependent density functional theory clearly shows the presence of the planar state. Furthermore, time-resolved fluorescence spectra resolves two excited states, and demonstrates how the CT reaction follows the solvation coordinate. Existence of the planar state and the solvation driven CT reaction makes it difficult to explain the fluorescence enhancement, but it allows to suggest a new application in studying amyloid fibrillation.