Introduction

Circularly polarized luminescence (CPL) measures the difference in the emission intensities of left- and right-handed circularly polarized light of chiral compounds. Unlike CD, CPL provides information on the excited state properties of chiral molecules.

Green fluorescence protein (GFP) is a protein that emits green fluorescence when exposed to ultraviolet light and has been shown to have chiroptical properties¹. This application note illustrates the CPL and CD spectra of GFP obtained with the CPL-300 and J-1500, respectively.

Experimental

Keywords

J-1500, Circular dichroism, CPL-300, Circularly polarized luminescence, Protein structure, Fluorescence, Biochemistry

Results

CD and absorption spectra (Figure 1, green) of a 0.03 mg/mL GFP solution was measured in the near-UV and visible regions. The GFP chromophore is observed in the visible region at 400 nm and the absorption bands due to the aromatic amino acid residues are observed in the near-UV region between 250 and 300 nm.  The CPL and fluorescence spectra were also obtained and show in blue in Figure 1. The characteristic fluorescent and CPL spectra of GFP are observed between 470-570 nm.

References

1. Hiromasa Goto, Isao Sawada, and Nobuhiko Nomura, International Journal of Polymeric Materials, 2010, 59, 786-792.