title: FMN-Based Fluorescent Proteins as Heavy Metal Sensors Against Mercury Ions.
abstract: Bacterial light-oxygen-voltage-sensing photoreceptor-derived flavin mononucleotide (FMN)- based fluorescent proteins act as a promising distinct class of fluorescent proteins utilized for various biomedical and biotechnological applications. The key property of its independency towards oxygen for its chromophore maturation has greatly helped this protein to outperform the other fluorescent proteins such as GFP and DsRed for anaerobic applications. Here, we describe the feasibility of FMN-containing fluorescent protein FbFP as a metal-sensing probe by measuring the fluorescence emission changes of a protein with respect to the concentration of metal ions. In the present study, we demonstrated the mercury-sensing ability of FbFP protein and the possible amino acids responsible for metal binding. A ratiometric approach was employed here in order to exploit the fluorescence changes observed at two different emission maxima with respect to Hg(2+) at micromolar concentration. The engineered variant FbFPC56I showed high sensitivity towards Hg(2+) and followed a good linear relationship from 0.1 to 3 µM of Hg(2+). Thus, further engineering with a rational approach would enable the FbFP to be developed as a novel and highly selective and sensitive biosensor for other toxic heavy metal ions as well.
authors.affiliation: School of Biotechnology, Department of Biochemistry, Yeungnam University, Gyeongsan 38541, Republic of Korea.
authors.forename: Yuvaraj
authors.initials: Y
authors.lastname: Ravikumar
authors.affiliation: Department of Bioscience and Biotechnology, Konkuk University, Seoul 05029, Republic of Korea.
authors.forename: Saravanan Prabhu
authors.initials: SP
authors.lastname: Nadarajan
authors.affiliation: School of Biotechnology, Department of Biochemistry, Yeungnam University, Gyeongsan 38541, Republic of Korea.
authors.forename: Chong-Soon
authors.initials: CS
authors.lastname: Lee
authors.affiliation: Department of Bioscience and Biotechnology, Konkuk University, Seoul 05029, Republic of Korea.
authors.forename: Seunho
authors.initials: S
authors.lastname: Jung
authors.affiliation: Department of Bioscience and Biotechnology, Konkuk University, Seoul 05029, Republic of Korea.
authors.forename: Dong-Ho
authors.initials: DH
authors.lastname: Bae
authors.affiliation: Department of Bioscience and Biotechnology, Konkuk University, Seoul 05029, Republic of Korea.
authors.forename: Hyungdon
authors.initials: H
authors.lastname: Yun
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D005486:Flavin Mononucleotide / Q000737:chemistry* / Q000378:metabolism; D005453:Fluorescence; D008164:Luminescent Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008628:Mercury / Q000032:analysis*
chemical_list: D008164:Luminescent Proteins; D005486:Flavin Mononucleotide; D008628:Mercury
keywords: FbFP protein; fluorescence quenching; mercury; ratiometric