De novo sequence redesign of a functional Ras binding domain globally inverted the surface charge distribution and led to extreme thermostability

2021 ◽  
Author(s):  
Ruicun Liu ◽  
Jichao Wang ◽  
Xiong Peng ◽  
Quan Chen ◽  
Haiyan Liu
Keyword(s):  
Surface Charge ◽  
Charge Distribution ◽  
De Novo ◽  
Binding Domain ◽  
Surface Charge Distribution

scholarly journals Mapping Surface Charge Distribution of Single-Cell via Charged Nanoparticle

Cells ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1519
Author(s):  
Leixin Ouyang ◽  
Rubia Shaik ◽  
Ruiting Xu ◽  
Ge Zhang ◽  
Jiang Zhe
Keyword(s):  
Cell Surface ◽  
Charge Density ◽  
Surface Charge ◽  
Charge Distribution ◽  
Surface Charge Density ◽  
Single Cells ◽  
Fluorescent Light ◽  
Fluorescent Nanoparticles ◽  
Cell Surface Charge ◽  
Surface Charge Distribution

Many bio-functions of cells can be regulated by their surface charge characteristics. Mapping surface charge density in a single cell’s surface is vital to advance the understanding of cell behaviors. This article demonstrates a method of cell surface charge mapping via electrostatic cell–nanoparticle (NP) interactions. Fluorescent nanoparticles (NPs) were used as the marker to investigate single cells’ surface charge distribution. The nanoparticles with opposite charges were electrostatically bonded to the cell surface; a stack of fluorescence distribution on a cell’s surface at a series of vertical distances was imaged and analyzed. By establishing a relationship between fluorescent light intensity and number of nanoparticles, cells’ surface charge distribution was quantified from the fluorescence distribution. Two types of cells, human umbilical vein endothelial cells (HUVECs) and HeLa cells, were tested. From the measured surface charge density of a group of single cells, the average zeta potentials of the two types of cells were obtained, which are in good agreement with the standard electrophoretic light scattering measurement. This method can be used for rapid surface charge mapping of single particles or cells, and can advance cell-surface-charge characterization applications in many biomedical fields.

EQCM as a unique tool for determination of ionic fluxes in microporous carbons as a function of surface charge distribution

2010 ◽  
Vol 12 (12) ◽  
pp. 1718-1721 ◽  
Author(s):  
Sergey Sigalov ◽  
Mikhael D. Levi ◽  
Gregory Salitra ◽  
Doron Aurbach ◽  
Joachim Maier
Keyword(s):  
Surface Charge ◽  
Charge Distribution ◽  
Microporous Carbons ◽  
Ionic Fluxes ◽  
Surface Charge Distribution

Gauging surface charge distribution of live cell membrane by ionic current change using scanning ion conductance microscopy

Nanoscale ◽  
2021 ◽  
Author(s):  
Feng Chen ◽  
Jin He ◽  
Prakash Manandhar ◽  
Yizi Yang ◽  
Peidang Liu ◽  
...  
Keyword(s):  
Cell Membrane ◽  
Surface Charge ◽  
Charge Distribution ◽  
Ionic Current ◽  
Live Cells ◽  
Ion Conductance ◽  
Physiological Conditions ◽  
Scanning Ion Conductance Microscopy ◽  
Surface Charge Distribution ◽  
Current Change

The distribution of surface charge and potential of cell membrane plays an indispensable role in cellular activities. However, probing surface charge of live cells in physiological conditions, until recently, remains...

Multiple pathways for denaturation of horse plasma gelsolin

1996 ◽  
Vol 74 (1) ◽  
pp. 101-107 ◽  
Author(s):  
Edward K. Koepf ◽  
Leslie D. Burtnick
Keyword(s):  
Surface Charge ◽  
Charge Distribution ◽  
Fluorescein Isothiocyanate ◽  
Heat Denaturation ◽  
Thermally Induced ◽  
Denatured State ◽  
Plasma Gelsolin ◽  
Surface Charge Distribution ◽  
Horse Plasma ◽  
Amine Groups

Gelsolin purified from horse plasma carries a surface charge distribution that greatly influences how the protein unfolds, aggregates, or precipitates as a function of temperature or concentration of chemical denaturant. Modification of gelsolin with fluorescein isothiocyanate replaces positive charges on amine groups with bulky, negatively charged fluorescein moieties. This postpones thermally induced precipitation by about 10 °C [Koepf, E.K., and Burtnick, L.D. 1993. Eur. J. Biochem. 212: 713–718]. Interaction with cations such as Ca2+ or guanidinium+ also alters the surface charge on gelsolin. This affects the structure of the protein in solution, modifies the pathway for unfolding, and moderates the onset of precipitation induced by chemical denaturants or heat. Denaturation of gelsolin is not interpretable in terms of a simple two-state cooperative mechanism. The pathway to a denatured state and intermediate structures present along the way depend upon the agent used to unfold the protein.Key words: gelsolin; denaturation, chemical, thermal, circular dichroism.

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