@article {YANG2021122533,
	title = {Detecting the formation of human c-KIT oncogene promoter G-Quadruplex by Taylor dispersion analysis},
	journal = {Talanta},
	volume = {233},
	year = {2021},
	pages = {122533},
	abstract = {The formation of G-quadruplex (G4) structures in oncogenic G-rich promoter regions are implicated in their biological functions, especially the inhibition of transcription. The binding of cations is thought to contribute to the stabilization of the G4 formation and competition against the duplex formation in the genomic sequence. Furthermore, it might affect the recognition of DNA-binding proteins. Therefore, measuring the interaction between G4 DNA and cations in a free solution environment is critical for evaluating G4 DNA biological functions. However, how binding to cations (K+ and NH4+) affects the folding equilibrium of the G4 structure remains unclear. In this work, a Taylor dispersion analysis (TDA) method using a capillary electrophoresis (CE) instrument was established for the quantitative characterization of the cation-dependent G4 formation in the human c-KIT oncogene promoter region, as well as diffusivities and hydrodynamic radii of DNA variations before and after folding. Our results showed that both K+ and NH4+ can induce the random-coiled c-KIT DNA to unfold and form a more unstretched intermediate state and then fold into tightly structured G4s with smaller size. The G4 size induced by NH4+ was smaller than that induced by K+ ions, though these two cations induced the c-KIT G4 DNA formation with similar binding constants (order of magnitude around 106~M-1). The TDA method can be widely used for rapid structural analyses of trace amounts of DNA mixtures, which effectively differentiate DNA variations or DNA-ligand complex conformations.},
	keywords = {binding constant, c-KIT oncogene, capillary electrophoresis, G-quadruplex, Taylor dispersion analysis},
	issn = {0039-9140},
	doi = {https://doi.org/10.1016/j.talanta.2021.122533},
	url = {https://www.sciencedirect.com/science/article/pii/S0039914021004549},
	author = {Yunhe Yang and Yang Yang and Shuangshuang Wang and Huihui Li and David D.Y. Chen}
}
@article {https://doi.org/10.1002/elps.202100077,
	title = {Quantitative characterization of human oncogene promoter G-quadruplex DNA-ligand interactions using a combination of mass spectrometry and capillary electrophoresis},
	journal = {ELECTROPHORESIS},
	volume = {42},
	number = {n/a},
	year = {2021},
	month = {05/2021},
	pages = {1450-1460},
	type = {Research},
	chapter = {1450},
	abstract = {<p>Abstract Human c-KIT oncogene is known to regulate cell growth and proliferation, and thus, acts as a probable target in the treatment of gastrointestinal tumors (GIST). To identify small molecule ligands which can specifically bind with the G-quadruplex (G4) in the c-KIT promoter region as potential antitumor agents, we propose the combination of electrospray ionization\&ndash;mass spectrometry (ESI-MS), capillary electrophoresis frontal analysis (CE-FA), and Taylor dispersion analysis (TDA) to accurately investigate the G4/ligands binding properties. First, ESI\&ndash;MS was used for initial screening of natural products (NPs). CE-FA was then used to calculate specific binding constants and the stoichiometry of the native state binding pair in solution. Next, TDA, a micro-capillary flow technique was used to examine the effect of the ligand binding on the diffusivity and particle size of the c-KIT G4. Two of the screened NPs, scopolamine butylbromide (L1) and isorhamnetin-3-O-neohesperidoside (L3), were found to specifically bind to the c-KIT G4 with binding constants of around 104 M\&ndash;1 and 1:1 stoichiometry in a free solution. TDA data showed that ligand binding (both L1 and L3) induced the c-KIT strands to fold into a tightly structured G4 with a decreased hydrodynamic radius. These ligands have the potential to be drug candidates for the regulation of c-KIT gene transcription by stabilizing the G4 structure. This methodology not only increased the speed of analysis but also improved its accuracy and specificity compared with the conventional binding approaches.</p>},
	keywords = {binding constant, c-KIT oncogene, Capillary electrophoresis frontal analysis, Electrospray ionization{\textendash}mass spectrometry, G-quadruplex, Taylor dispersion analysis},
	doi = {https://doi.org/10.1002/elps.202100077},
	url = {https://analyticalsciencejournals.onlinelibrary.wiley.com/doi/abs/10.1002/elps.202100077},
	author = {Wang, Shuangshuang and Yang, Yang and Yang, Yunhe and Li, Huihui and Chen, David D.Y.}
}
