Site-specific Fluorescent Labeling of Poly-histidine Sequences Using a Metal-chelating Cysteine

• Published in: Chemical biology & drug design Vol. 69; no. 1; pp. 31 - 40
• Main Authors: Krishnan, Beena, Szymanska, Aneta, Gierasch, Lila M.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.01.2007; Wiley
• Subjects: Binding Sites; Biochemistry & Molecular Biology; Bridged Bicyclo Compounds - chemistry; Chelating Agents - chemistry; Chemistry, Medicinal; Cross-Linking Reagents - chemistry; cysteine; Cysteine - analogs & derivatives; dibromobimane; fluorescence; Fluorescent Dyes - chemistry; His-tag; Histidine - chemistry; Life Sciences & Biomedicine; metal chelating; Nitrilotriacetic Acid - analogs & derivatives; Oligopeptides - chemistry; Organometallic Compounds - chemistry; Pharmacology & Pharmacy; protein tagging; Science & Technology; Spectrometry, Fluorescence; Staining and Labeling - methods; Substrate Specificity; RNA; cysteine; His-tag; ESCHERICHIA-COLI; UNNATURAL AMINO-ACIDS; LIVE CELLS; metal chelating; TAGGED PROTEINS; dibromobimane; fluorescence; protein tagging; AFFINITY; RECOMBINANT PROTEINS; IN-VIVO; SIGNAL RECOGNITION PARTICLE; BINDING
• ISSN: 1747-0277; 1747-0285
• DOI: 10.1111/j.1747-0285.2007.00463.x

Coupling genetically encoded target sequences with specific and selective labeling strategies has made it possible to utilize fluorescence spectroscopy in complex mixtures to investigate the structure, function, and dynamics of proteins. Thus, there is a growing need for a repertoire of such labeling approaches to deploy based on a given application and to utilize in combination with one another by orthogonal reactivity. We have developed a simple approach to synthesize a fluorescent probe that binds to a poly‐histidine sequence. The amino group of cysteine was converted into nitrilotriacetate to create a metal‐chelating cysteine molecule, Cys‐nitrilotriacetate. Two Cys‐nitrilotriacetate molecules were then cross‐linked using dibromobimane to generate a fluorophore capable of binding a His‐tag on a protein, NTA2‐BM. NTA2‐BM is a potential fluorophore for selective tagging of proteins in vivo.