Probing dimerization and intraprotein fluorescence resonance energy transfer in a far-red fluorescent protein from the sea anemone Heteractis crispa

Guillaume A. Lessard, Satoshi Habuchi, James H. Werner, Peter M. Goodwin, Frans De Schryver, Johan Hofkens, Mircea Cotlet
2008 Journal of Biomedical Optics  
Proteins from Anthozoa species are homologous to the green fluorescent protein ͑GFP͒ from Aequorea victoria but with absorption/emission properties extended to longer wavelengths. HcRed is a far-red fluorescent protein originating from the sea anemone Heteractis crispa with absorption and emission maxima at 590 and 650 nm, respectively. We use ultrasensitive fluorescence spectroscopic methods to demonstrate that HcRed occurs as a dimer in solution and to explore the interaction between
more » ... res within such a dimer. We show that red chromophores within a dimer interact through a Förster-type fluorescence resonance energy transfer ͑FRET͒ mechanism. We present spectroscopic evidence for the presence of a yellow chromophore, an immature form of HcRed. This yellow chromophore is involved in directional FRET with the red chromophore when both types of chromophores are part of one dimer. We show that by combining ensemble and single molecule methods in the investigation of HcRed, we are able to sort out subpopulations of chromophores with different photophysical properties and to understand the mechanism of interaction between such chromophores. This study will help in future quantitative microscopy investigations that use HcRed as a fluorescent marker.
doi:10.1117/1.2937477 pmid:18601536 fatcat:cadlcx4zgzghzktyhm3l6bw3u4