title: A green fluorescent protein with photoswitchable emission from the deep sea.
abstract: A colorful variety of fluorescent proteins (FPs) from marine invertebrates are utilized as genetically encoded markers for live cell imaging. The increased demand for advanced imaging techniques drives a continuous search for FPs with new and improved properties. Many useful FPs have been isolated from species adapted to sun-flooded habitats such as tropical coral reefs. It has yet remained unknown if species expressing green fluorescent protein (GFP)-like proteins also exist in the darkness of the deep sea. Using a submarine-based and -operated fluorescence detection system in the Gulf of Mexico, we discovered ceriantharians emitting bright green fluorescence in depths between 500 and 600 m and identified a GFP, named cerFP505, with bright fluorescence emission peaking at 505 nm. Spectroscopic studies showed that approximately 15% of the protein bulk feature reversible ON/OFF photoswitching that can be induced by alternating irradiation with blue und near-UV light. Despite being derived from an animal adapted to essentially complete darkness and low temperatures, cerFP505 maturation in living mammalian cells at 37 degrees C, its brightness and photostability are comparable to those of EGFP and cmFP512 from shallow water species. Therefore, our findings disclose the deep sea as a potential source of GFP-like molecular marker proteins.
authors.affiliation: Institute of General Zoology and Endocrinology, University of Ulm, Ulm, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Vogt
authors.forename: Cecilia
authors.initials: C
authors.lastname: D'Angelo
authors.forename: Franz
authors.initials: F
authors.lastname: Oswald
authors.forename: Andrea
authors.initials: A
authors.lastname: Denzel
authors.forename: Charles H
authors.initials: CH
authors.lastname: Mazel
authors.forename: Mikhail V
authors.initials: MV
authors.lastname: Matz
authors.forename: Sergey
authors.initials: S
authors.lastname: Ivanchenko
authors.forename: G Ulrich
authors.initials: GU
authors.lastname: Nienhaus
authors.forename: Jörg
authors.initials: J
authors.lastname: Wiedenmann
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D037421:Anthozoa / Q000235:genetics; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000378:metabolism; D005453:Fluorescence; D049452:Green Fluorescent Proteins / Q000737:chemistry* / Q000302:isolation & purification; D007448:Invertebrates; D008027:Light; D008164:Luminescent Proteins / Q000737:chemistry; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid; D013050:Spectrometry, Fluorescence / Q000379:methods; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D013696:Temperature
chemical_list: D018076:DNA, Complementary; D008164:Luminescent Proteins; D049452:Green Fluorescent Proteins