Zhaoqi Yang

Ultrasensitive Colorimetric DNA Detection using a Combination of Rolling Circle Amplification and Nicking Endonuclease‐Assisted Nanoparticle Amplification (NEANA)

A combination of rolling circle amplification and nicking endonuclease-assisted nanoparticle amplification (NEANA) is used for the rapid, colorimetric detection of DNA. The integration of rolling circle amplification into the NEANA approach allows for detection of oligonucleotides with arbitrary sequences at ultralow concentrations.

EcoRI-Modified Gold Nanoparticles for Dual-Mode Colorimetric Detection of Magnesium and Pyrophosphate Ions

Magnesium in its ionic form (Mg 2 + ) is essential for many physiological processes, including much of metabolism, enzyme activation and catalysis, photosynthesis development, signal transduction, and protection against hypertension and blood vessel spasm. [ 1 ] Therefore, it has been long recognized that for suitable diagnosis of various ailments, the accurate and rapid measurement of Mg 2 + is important. Additionally, the ability to detect Mg 2 + is also important in the area of environmental monitoring for effective pollution control. [ 2 ]

Manipulating DNA writhe through varying DNA sequences.

It is demonstrated that the shapes and magnitudes of DNA writhe can be precisely manipulated solely through maneuvering the nucleotide sequence of DNA and without the assistance of topoisomerases.

Concise synthesis of Cannabisin G

Cannabisin G (1), a naturally occurring lignanamide, was synthesized in 45% overall yield starting from 3-tert-butyl ethyl ferulate (6). An oxidative coupling by potassium ferricyanide in an alkaline media serves as the key step to construct the biphenylbutadiene skeleton of 1 with high regioselectivity.

Precise engineering and visualization of signs and magnitudes of DNA writhe on the basis of PNA invasion

It is demonstrated that the right and left handedness of DNA supercoils can be engineered precisely and readily at the molecular level in vitro through utilization of the invading property of peptide nucleic acid.

Recognition of forcible curvature in circular DNA by human topoisomerase I

A series of forcible curved circular DNAs (cDNAs) were prepared to investigate the recognition features of human Topoisomerase I (hTopo I). The IC(50) can be modulated by the curvature degrees of cDNA. In addition, preferential bindings of hTopo I to cDNA with high curvature have been observed by AFM and EMSA.

Observation of backbone self-crossings of organismal DNAs through atomic force microscopy

It is demonstrated in our studies that intrinsic curvatures of organismal DNAs could lead to the generation of duplex backbone self-crossings in their relaxed forms. In addition, the backbone self-crossings of the organismal DNAs could be readily confirmed through atomic force microscopic examination.

Intrinsic curvature in duplex DNA inhibits Human Topoisomerase I.

Human Topoisomerase I (hTopo I) have been known as a potential target for cancer therapy. A series of duplex DNA with different intrinsic curvatures have been designed as inhibitors to hTopo I. The activities of hTopo I on relaxing supercoiled plasmid pUC 19 are apparently diminished in the presence of the curved DNA. More potent inhibitions and smaller IC(50) are achieved by duplex DNA with higher curvatures. EMSA indicates that hTopo I can recognize the curved DNA through binding interactions. Our studies demonstrate that the activity of hTopo I can be modulated by the intrinsic curvature of linear DNA and provide a new avenue to design curved DNA as hTopo I inhibitors with high therapeutic efficiency and low toxicity.

Conformational organizations of G-quadruplexes composed of d(G4Tn)3G4

Structural polymorphism is one of the important issues with regard to G-quadruplexes because the structural diversity may significantly affect their biological functions in vivo and their physical property in nano-material. A series of oligonucleotides with four repeat guanines sequence [d(G(4)T(n))(3)G(4) (n=1-6)] were designed. In this study, the effects of loop length on the formation of structures of G-quadruplex were investigated through the result of CD (circular dichroism) and 20% non-denatured polyacrylamide gel electrophoresis. Our studies demonstrate that the length of loop in 100mM KCl solution could predict the conformation of G-quadruplex.

Interference of intrinsic curvature of DNA by DNA-intercalating agents

It has been demonstrated in our studies that the intrinsic curvature of DNA can be easily interrupted by low concentrations of chloroquine and ethidium bromide. In addition, the changes of DNA curvature caused by varying the concentration of these two DNA intercalators can be readily verified through using an atomic force microscope.