title: Autofluorescent proteins with excitation in the optical window for intravital imaging in mammals.
abstract: Fluorescent proteins have become valuable tools for biomedical research as protein tags, reporters of gene expression, biosensor components, and cell lineage tracers. However, applications of fluorescent proteins for deep tissue imaging in whole mammals have been constrained by the opacity of tissues to excitation light below 600 nm, because of absorbance by hemoglobin. Fluorescent proteins that excite efficiently in the "optical window" above 600 nm are therefore highly desirable. We report here the evolution of far-red fluorescent proteins with peak excitation at 600 nm or above. The brightest one of these, Neptune, performs well in imaging deep tissues in living mice. The crystal structure of Neptune reveals a novel mechanism for red-shifting involving the acquisition of a new hydrogen bond with the acylimine region of the chromophore.
authors: Department of Pharmacology, University of California, San Diego, La Jolla, 92093, USA.
authors: Michael Z
authors: MZ
authors: Lin
authors: Michael R
authors: MR
authors: McKeown
authors: Ho-Leung
authors: HL
authors: Ng
authors: Todd A
authors: TA
authors: Aguilera
authors: Nathan C
authors: NC
authors: Shaner
authors: Robert E
authors: RE
authors: Campbell
authors: Stephen R
authors: SR
authors: Adams
authors: Larry A
authors: LA
authors: Gross
authors: Wendy
authors: W
authors: Ma
authors: Tom
authors: T
authors: Alber
authors: Roger Y
authors: RY
authors: Tsien
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D018360:Crystallography, X-Ray; D005456:Fluorescent Dyes / Q000737:chemistry*; D006860:Hydrogen Bonding; D008164:Luminescent Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D000097573:Red Fluorescent Protein
chemical_list: D005456:Fluorescent Dyes; D008164:Luminescent Proteins; D011993:Recombinant Fusion Proteins; D000097573:Red Fluorescent Protein; C547377:neptune protein