121st General Meeting of the KCS

Type Poster Presentation
Area Physical Chemistry
Room No. Event Hall
Time 4월 20일 (금요일) 11:00~12:30
Code PHYS.P-89
Subject Investigation of Photophysical Properties of RFPs for Enhanced Performance
Authors So Hyeong Sohn, Taecheon Lyu, Ralph Jimenez1,*, Taiha Joo*
Department of Chemistry, Pohang University of Science and Technology, Korea
1Department of Chemistry & Biochemistry, University of Colorado, United States
Abstract Fluorescent protein (FP) has been spotlighted in the molecular biology due to its advantages such as non-toxicity, and high quantum yield for protein tags, reporters of gene expression, and cell lineage tracers. Although the study of green FP (GFP) was intensively achieved since it was discovered from jellyfish in advance of other FPs, hemoglobin and myoglobin strongly absorb <600 nm, which corresponds to the emission of GFPs. Recently, many researchers have been paying attention to red FPs (RFPs), which can overcome the poor transmittance of GFP. We study a rational approach to the improved performance by investigating the excited-state dynamics of RFPs even if RFPs were generally synthesized by random mutation to achieve high performance. The steady-state and time-resolved fluorescence experiments were performed for four RFPs of TagRFP group, the subfamily of RFPs, (mKateS, mNeptune1, mNeptune2.5, mCardinal2) at various temperatures from 20 to 295K. The low-temperature environment provides excited-state dynamics unambiguously by restricting conformers and undesired dynamics such as solvation. It was reported that TagRFP group has the peculiar feature of spectral blue shift over time in the liquid phase. We concluded that the conformer, which has twice longer radiative decay time from high energy state than the main conformer, were involved in the spectral blue shift. There is another conformer with a high extinction coefficient at low temperature, resulting in a ~6 times brighter fluorescence at 20K. We plan to use QM/MM calculations to find the detailed structure of various conformers, and it can be expected to reveal specific structures of the RFPs with high quantum yield and large Stokes shift.
E-mail shsohn@postech.ac.kr