Change in Rigidity in the Activated Form of the Glucose/Galactose Receptor from Escherichia coli: A Phenomenon that Will Be Key to the Development of Biosensors

Sokolov, Igor; Subba-Rao, Venkatesh; Luck, Linda A.

doi:10.1529/biophysj.105.060442

Cited by 28 publications

(25 citation statements)

References 30 publications

(39 reference statements)

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“…Atomic force microscopy (AFM) is a quite versatile tool to detect physical presence of molecules on the cell surfaces (18)(19)(20)(21), in particular, the pericellular coat (22)(23)(24)(25)(26). It is due to a broad range of forces the AFM probe can exert on the sample surface.…”

Section: Introductionmentioning

confidence: 99%

Pericellular Brush and Mechanics of Guinea Pig Fibroblast Cells Studied with AFM

Dokukin

Ablaeva

Kalaparthi

et al. 2016

Biophysical Journal

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The atomic force microscopy (AFM) indentation method combined with the brush model can be used to separate the mechanical response of the cell body from deformation of the pericellular layer surrounding biological cells. Although self-consistency of the brush model to derive the elastic modulus of the cell body has been demonstrated, the model ability to characterize the pericellular layer has not been explicitly verified. Here we demonstrate it by using enzymatic removal of hyaluronic content of the pericellular brush for guinea pig fibroblast cells. The effect of this removal is clearly seen in the AFM force-separation curves associated with the pericellular brush layer. We further extend the brush model for brushes larger than the height of the AFM probe, which seems to be the case for fibroblast cells. In addition, we demonstrate that an extension of the brush model (i.e., double-brush model) is capable of detecting the hierarchical structure of the pericellular brush, which, for example, may consist of the pericellular coat and the membrane corrugation (microridges and microvilli). It allows us to quantitatively segregate the large soft polysaccharide pericellular coat from a relatively rigid and dense membrane corrugation layer. This was verified by comparison of the parameters of the membrane corrugation layer derived from the force curves collected on untreated cells (when this corrugation membrane part is hidden inside the pericellular brush layer) and on treated cells after the enzymatic removal of the pericellular coat part (when the corrugations are exposed to the AFM probe). We conclude that the brush model is capable of not only measuring the mechanics of the cell body but also the parameters of the pericellular brush layer, including quantitative characterization of the pericellular layer structure.

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Section: Introductionmentioning

confidence: 99%

Pericellular Brush and Mechanics of Guinea Pig Fibroblast Cells Studied with AFM

Dokukin

Ablaeva

Kalaparthi

et al. 2016

Biophysical Journal

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“…Enteric bacteria (1) use glucose/galactose binding protein (GGBP) in separate pathways to actively transport methylgalactosides across the cell membrane (2,3) and to chemically sense them as part of the swimming regulatory scheme (1,4,5). In addition to the fundamental importance of GGBP in the molecular and cellular biology of enteric bacteria, the potential to exploit GGBP for glucose detection has motivated extensive study (6)(7)(8)(9)(10)(11)(12)(13)(14)(15). Crystallographic (16) and bulk steady-state (6,7,(17)(18)(19)) studies of GGBP have investigated its binding of glucose, which is usually described by a single (5)(6)(7)19) binding constant, though some studies have suggested otherwise (17,18).…”

Section: Introductionmentioning

confidence: 99%

Protein Free Energy Landscapes Remodeled by Ligand Binding

Messina

Talaga

2007

Biophysical Journal

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Glucose/galactose binding protein (GGBP) functions in two different larger systems of proteins used by enteric bacteria for molecular recognition and signaling. Here we report on the thermodynamics of conformational equilibrium distributions of GGBP. Three fluorescence components appear at zero glucose concentration and systematically transition to three components at high glucose concentration. Fluorescence anisotropy correlations, fluorescent lifetimes, thermodynamics, computational structure minimization, and literature work were used to assign the three components as open, closed, and twisted conformations of the protein. The existence of three states at all glucose concentrations indicates that the protein continuously fluctuates about its conformational state space via thermally driven state transitions; glucose biases the populations by reorganizing the free energy profile. These results and their implications are discussed in terms of the two types of specific and nonspecific interactions GGBP has with cytoplasmic membrane proteins.

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“…It allows measurement of the elasticity (rigidity) of the surfaces [e.g. of cells and molecules (17)(18)(19)(20)], friction between the AFM probe, and the surface of study (21)(22)(23).…”

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confidence: 99%

Atomic force microscopy characterization of corneocytes: effect of moisturizer on their topology, rigidity, and friction

Gaikwad

Vasilyev

Datta

et al. 2010

Skin Research and Technology

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Change in Rigidity in the Activated Form of the Glucose/Galactose Receptor from Escherichia coli: A Phenomenon that Will Be Key to the Development of Biosensors

Cited by 28 publications

References 30 publications

Pericellular Brush and Mechanics of Guinea Pig Fibroblast Cells Studied with AFM

Pericellular Brush and Mechanics of Guinea Pig Fibroblast Cells Studied with AFM

Protein Free Energy Landscapes Remodeled by Ligand Binding

Atomic force microscopy characterization of corneocytes: effect of moisturizer on their topology, rigidity, and friction

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