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Effects of macromolecular crowding on intracellular diffusion from a single particle perspective.

Hall D, Hoshino M - Biophys Rev (2010)

Bottom Line: Through a range of intermolecular forces and pseudo-forces, this complex background environment may cause biochemical reactions to behave differently to their in vitro counterparts.Engaging the subject from the perspective of a single particle's motion, we place the focus of our review on two areas: (1) experimental procedures for conducting single particle tracking experiments within cells along with methods for extracting information from these experiments; (2) theoretical factors affecting the translational diffusion of single molecules within crowded two-dimensional membrane and three-dimensional solution environments.We conclude by discussing a number of recent publications relating to intracellular diffusion in light of the reviewed material.

View Article: PubMed Central - PubMed

ABSTRACT
Compared to biochemical reactions taking place in relatively well-defined aqueous solutions in vitro, the corresponding reactions happening in vivo occur in extremely complex environments containing only 60-70% water by volume, with the remainder consisting of an undefined array of bio-molecules. In a biological setting, such extremely complex and volume-occupied solution environments are termed 'crowded'. Through a range of intermolecular forces and pseudo-forces, this complex background environment may cause biochemical reactions to behave differently to their in vitro counterparts. In this review, we seek to highlight how the complex background environment of the cell can affect the diffusion of substances within it. Engaging the subject from the perspective of a single particle's motion, we place the focus of our review on two areas: (1) experimental procedures for conducting single particle tracking experiments within cells along with methods for extracting information from these experiments; (2) theoretical factors affecting the translational diffusion of single molecules within crowded two-dimensional membrane and three-dimensional solution environments. We conclude by discussing a number of recent publications relating to intracellular diffusion in light of the reviewed material.

No MeSH data available.


Colour-coded description of frictional coefficient experienced by a tracer particle (R = 2 nm, H = 5 nm) in a 2D fluid membrane  at 37°C bounded by a hard wall (a) at limiting dilution (b) at θ = 0.35 (as approximated by Eq. 11b). Note the stagnant regions adjacent to the walls and high local densities of particles shown in brighter red, indicating higher viscosity/higher local frictional coefficient
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Fig6: Colour-coded description of frictional coefficient experienced by a tracer particle (R = 2 nm, H = 5 nm) in a 2D fluid membrane at 37°C bounded by a hard wall (a) at limiting dilution (b) at θ = 0.35 (as approximated by Eq. 11b). Note the stagnant regions adjacent to the walls and high local densities of particles shown in brighter red, indicating higher viscosity/higher local frictional coefficient

Mentions: In Eqs. 11a and 11b, ϕ and θ refer to the local fraction of volume and area, respectively, occupied by all other explicitly recognized particles9 within a sphere or circle of radius 4Ri centred at position ri . As an example, Fig. 6 describes the altered frictional force resulting from HI effects experienced by a tracer protein Ri = 2 nm) in an enclosed 2D membrane at either limiting dilution or under crowded conditions (θ = 0.4). The equations derived above should be seen as a first order inclusion of HI as they ignore differences in the perpendicular and parallel components of the viscosity predicted by higher order theory (Elimelech et al. 1995; Dhont 1996; Batchelor 2000).Fig. 6


Effects of macromolecular crowding on intracellular diffusion from a single particle perspective.

Hall D, Hoshino M - Biophys Rev (2010)

Colour-coded description of frictional coefficient experienced by a tracer particle (R = 2 nm, H = 5 nm) in a 2D fluid membrane  at 37°C bounded by a hard wall (a) at limiting dilution (b) at θ = 0.35 (as approximated by Eq. 11b). Note the stagnant regions adjacent to the walls and high local densities of particles shown in brighter red, indicating higher viscosity/higher local frictional coefficient
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2957576&req=5

Fig6: Colour-coded description of frictional coefficient experienced by a tracer particle (R = 2 nm, H = 5 nm) in a 2D fluid membrane at 37°C bounded by a hard wall (a) at limiting dilution (b) at θ = 0.35 (as approximated by Eq. 11b). Note the stagnant regions adjacent to the walls and high local densities of particles shown in brighter red, indicating higher viscosity/higher local frictional coefficient
Mentions: In Eqs. 11a and 11b, ϕ and θ refer to the local fraction of volume and area, respectively, occupied by all other explicitly recognized particles9 within a sphere or circle of radius 4Ri centred at position ri . As an example, Fig. 6 describes the altered frictional force resulting from HI effects experienced by a tracer protein Ri = 2 nm) in an enclosed 2D membrane at either limiting dilution or under crowded conditions (θ = 0.4). The equations derived above should be seen as a first order inclusion of HI as they ignore differences in the perpendicular and parallel components of the viscosity predicted by higher order theory (Elimelech et al. 1995; Dhont 1996; Batchelor 2000).Fig. 6

Bottom Line: Through a range of intermolecular forces and pseudo-forces, this complex background environment may cause biochemical reactions to behave differently to their in vitro counterparts.Engaging the subject from the perspective of a single particle's motion, we place the focus of our review on two areas: (1) experimental procedures for conducting single particle tracking experiments within cells along with methods for extracting information from these experiments; (2) theoretical factors affecting the translational diffusion of single molecules within crowded two-dimensional membrane and three-dimensional solution environments.We conclude by discussing a number of recent publications relating to intracellular diffusion in light of the reviewed material.

View Article: PubMed Central - PubMed

ABSTRACT
Compared to biochemical reactions taking place in relatively well-defined aqueous solutions in vitro, the corresponding reactions happening in vivo occur in extremely complex environments containing only 60-70% water by volume, with the remainder consisting of an undefined array of bio-molecules. In a biological setting, such extremely complex and volume-occupied solution environments are termed 'crowded'. Through a range of intermolecular forces and pseudo-forces, this complex background environment may cause biochemical reactions to behave differently to their in vitro counterparts. In this review, we seek to highlight how the complex background environment of the cell can affect the diffusion of substances within it. Engaging the subject from the perspective of a single particle's motion, we place the focus of our review on two areas: (1) experimental procedures for conducting single particle tracking experiments within cells along with methods for extracting information from these experiments; (2) theoretical factors affecting the translational diffusion of single molecules within crowded two-dimensional membrane and three-dimensional solution environments. We conclude by discussing a number of recent publications relating to intracellular diffusion in light of the reviewed material.

No MeSH data available.