PubMed Health⌕ Search

Biomedical subjects

Yaxin Jiang

Publications and source records attributed to Yaxin Jiang.

5 recordsLinked to original sources
PubMed2004

Signaling aptamer/protein binding by a molecular light switch complex.

A novel method of signaling aptamer/protein binding for aptamer-based protein detection has been developed using a molecular light switch complex, [Ru(phen)2(dppz)]2+. The method takes advantage of the sensitive luminescence signal change of [Ru(phen)2(dppz)]2+ intercalating to the aptamer upon protein/aptamer binding. A 37-nt DNA aptamer against immunoglobulin E (IgE) was first tested as a model system. The luminescence of the [Ru(phen)2(dppz)]2+/IgE aptamer decreased with the increase of IgE. By monitoring the luminescence change, we were able to detect the binding events between the aptamer and IgE for IgE quantitation in homogeneous solutions as well as in serum. The assay was highly selective and sensitive with a detection limit of 100 pM for IgE. This new method is very simple and without the need for the covalent coupling of fluorophores to aptamers. The generalizability of the method was demonstrated by the direct detection of two other proteins, oncoprotein platelet derived growth factor-BB (PDGF-BB) using its DNA aptamer and alpha-thrombin using its RNA aptamer. This new approach is expected to promote the exploitation of aptamer-based biosensors for protein assays in biochemical and biomedical studies.

Aptamers, Nucleotide↗
PubMed2004

Measuring specific interaction of transcription factor ZmDREB1A with its DNA responsive element at the molecular level.

Specific interactions between transcription factors and DNA responsive elements are of fundamental importance in understanding how genetic regulatory proteins control gene transcription. Here we have developed a new method of using atomic force microscopy (AFM) to quantitatively study the single molecular specific interaction between ZmDREB1A, a transcription factor from maize, and its DNA responsive element, dehydration-responsive element (DRE) with core sequence A/GCCGAC. It was found that ZmDREB1A bound to both DRE ACCGAC and GCCGAC efficiently. The single molecular interaction forces of ZmDREB1A with DRE A/GCCGAC were determined to be 101 +/- 5 and 108 +/- 3 pN, respectively. The point mutation of ZmDREB1A in its DNA-binding domain or single base substitution of the DRE core sequence greatly reduced the binding affinity, demonstrating the high sensitivity of the AFM measurements. AFM is expected to be a simple, quick, sensitive and reliable method that offers valuable information for the characterization of transcription factors and the identification of their potential DNA responsive elements in functional genomics research.

Arabidopsis Proteins↗
PubMed2004

Study of the effect of metal ion on the specific interaction between protein and aptamer by atomic force microscopy.

We have studied the effect of metal ions on the specific interaction between a protein, immunoglobulin E (IgE), and its 37-nt DNA aptamer with atomic force microscopy (AFM). Protein aptamers are a new class of synthetic single-stranded DNA/RNA oligonucleotide generated from in vitro selection to selectively bind with target proteins. The IgE aptamers have been developed and are expected to be promising reagents in IgE detection and new anti-allergic drug development. It is known that the presence of metal ions in the buffer usually has a strong effect on the affinity of single-stranded DNA for protein. In this work, the effect of two representative monovalent ion and divalent ion on the binding of IgE and the aptamer has been studied at the single-molecule level. The results from the AFM force measurements show that the metal ions not only reduce the single-molecular rupture force but also reduce the number of bonds formed between IgE and the aptamer.

DNA↗
PubMed2003

Specific aptamer-protein interaction studied by atomic force microscopy.

Aptamers are a new class of synthetic DNA/RNA oligonucleotides generated from in vitro selection to selectively bind with various molecules. Due to their molecular recognition capability for proteins, aptamers are becoming promising reagents in protein detection and new drug development. In this study, the specific interaction between the protein immunoglobulin E (IgE) and its 37-nt aptamer has been measured directly by atomic force microscopy. The single-molecule unbinding force between IgE and the aptamer is determined using the Poisson statistical method. The individual unbinding force between IgE and its monoclonal antibody has also been obtained and compared to that between IgE and the aptamer. The results reveal the high affinity of the aptamer to protein, which could match or even surpass that of the antibody to its antigen.

Humans↗