title: In vivo targeting of organic calcium sensors via genetically selected peptides.
abstract: A library of constrained peptides that form stable folded structures was screened for aptamers that bind with high affinity to the fluorescent dye Texas red. Two selected clones had binding constants to Texas red of 25 and 80 pM as phage and binding had minimal effects on the fluorescence of Texas red. The peptides interact with distinct but overlapping regions of Texas red. One peptide bound to X-rhod calcium sensors, which share the same core fluorophore as Texas red. These dyes retained calcium sensitivity when bound to the peptide. This peptide was used to label a fusion protein with X-rhod-5F in vivo, and X-rhod sensed changes in calcium locally. Thus, minimal, constrained peptides can functionally bind to environmentally sensitive dyes or other organic agents in biological contexts, suggesting tools for in vivo imaging and analysis.
authors.affiliation: Department of Molecular Pharmacology, Stanford University School of Medicine, Stanford, CA 94305, USA.
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Marks
authors.forename: Michael
authors.initials: M
authors.lastname: Rosinov
authors.forename: Garry P
authors.initials: GP
authors.lastname: Nolan
mesh_terms: D000595:Amino Acid Sequence; D017104:Bacteriophage M13 / Q000737:chemistry / Q000378:metabolism; D001435:Bacteriophages / Q000235:genetics / Q000378:metabolism; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D002118:Calcium / Q000378:metabolism*; D019281:Dimerization; D005456:Fluorescent Dyes / Q000032:analysis / Q000737:chemistry; D008969:Molecular Sequence Data; D019151:Peptide Library; D010455:Peptides / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D011485:Protein Binding; D013050:Spectrometry, Fluorescence; D014966:Xanthenes / Q000032:analysis / Q000737:chemistry
chemical_list: D005456:Fluorescent Dyes; D019151:Peptide Library; D010455:Peptides; D014966:Xanthenes; C034657:Texas red; D002118:Calcium