Gold-Nanoparticle-Based Assay for Instantaneous Detection of Nuclear Hormone Receptor−Response Elements Interactions

• Published in: Analytical chemistry (Washington) Vol. 82; no. 7; pp. 2759 - 2765
• Main Authors: Tan, Yen Nee, Su, Xiaodi, Liu, Edison T, Thomsen, Jane S
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.04.2010
• Subjects: Analytical chemistry; Base Sequence; Binding sites; Biological and medical sciences; Biosensors; Biotechnology; Chemistry; Deoxyribonucleic acid; DNA; DNA - chemistry; Estrogen Receptor alpha - chemistry; Estrogen Receptor alpha - metabolism; Estrogen Receptor beta - chemistry; Estrogen Receptor beta - metabolism; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; General, instrumentation; Gold; Gold - chemistry; Hormones; Metal Nanoparticles - chemistry; Methods. Procedures. Technologies; Nanoparticles; Protein Binding; Response Elements; Spectrometric and optical methods; Spectrophotometry, Ultraviolet - methods; Various methods and equipments; Stoichiometry; Particle size; Nuclear receptor; Chemical analysis; Choice; Nanoparticle; Stabilization; Estrogen; Citrate; Instrumentation; Colorimetry; Selectivity; Molecular size; Probe; Aggregation; Salt; Sample preparation; Protection; Human; Gold; Use; Color; DNA binding protein; Response element; Biosensor; DNA; Affinity; Parameter; Detection; Subtype
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/ac9026498

Gold nanoparticles (AuNPs) are widely used as colorimetric probes for biosensing, relying on their unique particle size-dependent and/or interparticle distance-dependent extinction spectrum and solution color. Herein, we describe an AuNP-based colorimetric assay to detect binding interactions between nuclear hormone receptors and their corresponding DNA-binding elements, particularly the human estrogen receptors (ERα and ERβ) and their cognate estrogen response elements (EREs). We found that the protein−DNA (ER−ERE) complexes can stabilize citrate anion-capped AuNPs against salt-induced aggregation to a larger extent than the protein (ER) or the DNA (ERE) alone, due to their unique molecular size and charge properties that provide a strong electrosteric protection. Moreover, our results show that the extent of stabilization is sequence-dependent and can distinguish a single base variation in the ERE associated with minor changes in protein−DNA binding affinity. With this assay, many important parameters of protein−DNA binding events (e.g., sequence selectivity, distinct DNA binding properties of protein subtypes, binding stoichiometry, and sequence-independent transient binding) can be determined instantly without using labels, tedious sample preparations, and sophisticated instrumentation. These benefits, in particular the high-throughput potential, could enable this assay to become the assay of choice to complement conventional techniques for large scale characterization of protein−DNA interactions, a key aspect in biological research.