Fractional Stokes−Einstein Relationship in Biological Colloids:  Role of Mixed Stick−Slip Boundary Conditions

Chirico, Giuseppe; Placidi, M; Cannistraro, Salvatore

doi:10.1021/jp982774w

Cited by 13 publications

(11 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In support of our observation that diffusion of tracer particles is anomalous in polymer solutions, it has very recently been shown using scale-dependent FCS measurements that the diffusion of dyes in polymer solutions was slightly anomalous (78). Furthermore, it was reported several times that the measured diffusion coefficients of proteins point to a difference between macroscopic and microscopic viscosities (10,73,77), which may result in anomalous diffusion at intermediate length scales for these proteins.…”

Section: Discussionsupporting

confidence: 85%

“…This is an unexpected result because for diffusing point obstacles interacting with a point tracer through excluded volume effects, simulations either do not show anomalous diffusion (25), or they show anomalous diffusion only at very short timescales (72). Furthermore, some groups have measured the diffusion of tracers in solutions crowded with mobile random-coiled polymers or globular proteins without observing or reporting this diffusion to be anomalous (73)(74)(75)(76)(77). However, our experiments and analysis show very clearly otherwise.…”

Section: Discussionmentioning

confidence: 55%

See 1 more Smart Citation

Anomalous Diffusion of Proteins Due to Molecular Crowding

Banks

Fradin

2005

Biophysical Journal

730

738

View full text Add to dashboard Cite

We have studied the diffusion of tracer proteins in highly concentrated random-coil polymer and globular protein solutions imitating the crowded conditions encountered in cellular environments. Using fluorescence correlation spectroscopy, we measured the anomalous diffusion exponent alpha characterizing the dependence of the mean-square displacement of the tracer proteins on time, r(2)(t) approximately t(alpha). We observed that the diffusion of proteins in dextran solutions with concentrations up to 400 g/l is subdiffusive (alpha < 1) even at low obstacle concentration. The anomalous diffusion exponent alpha decreases continuously with increasing obstacle concentration and molecular weight, but does not depend on buffer ionic strength, and neither does it depend strongly on solution temperature. At very high random-coil polymer concentrations, alpha reaches a limit value of alpha(l) approximately 3/4, which we take to be the signature of a coupling between the motions of the tracer proteins and the segments of the dextran chains. A similar, although less pronounced, subdiffusive behavior is observed for the diffusion of streptavidin in concentrated globular protein solutions. These observations indicate that protein diffusion in the cell cytoplasm and nucleus should be anomalous as well, with consequences for measurements of solute diffusion coefficients in cells and for the modeling of cellular processes relying on diffusion.

show abstract

Section: Discussionsupporting

confidence: 85%

Section: Discussionmentioning

confidence: 55%

Anomalous Diffusion of Proteins Due to Molecular Crowding

Banks

Fradin

2005

Biophysical Journal

730

738

View full text Add to dashboard Cite

show abstract

“…79 This altered scaling relationship between D T and s a has significant implications for rates of reaction in glass-forming and other complex liquids in that it implies a corresponding fractional power law relationship between the rate of reaction k d and s a , i.e., k d $ s a Àd . Such a relationship is commonly observed in water 80 and numerous other complex liquids 79,[81][82][83][84][85] under conditions where dynamic heterogeneity is prevalent. In such systems, D T can be enhanced by as much as five orders of magnitude at T g 78 over the value expected in the classical Stokes-Einstein picture.…”

Section: Potential Mechanismsmentioning

confidence: 74%

β-Relaxation governs protein stability in sugar-glass matrices

2012

View full text Add to dashboard Cite

The stabilizing effect of sugar-glass matrix materials for freeze-drying proteins or nucleic acids has been variously ascribed to the thermodynamic effect of 'water replacement' by sugar molecules or to the kinetic effect of slowed a relaxation associated with sugar matrix vitrification. While evidence for each of these hypotheses exists, we show that neither can adequately account for the observed stabilization of proteins embedded in sugar-glasses. Instead, we find firm evidence that protein stability in these glasses is directly linked to high frequency b relaxation processes of the sugar matrix. Specifically, we observe that when the b relaxation time, s b , of sugar-glasses is increased with antiplasticizing additives, protein stability increases in linear proportion to the increase in s b , even though these same additives simultaneously decrease the glass transition temperature, T g , and the a relaxation time, s a , of the sugar matrix materials. Moreover, we find that while sugars 'replace' water by stabilizing protein native-like conformation in the dry state, the resulting enhanced protein conformational stability does not have a significant impact on the degradation rate of the proteins in sugar-glasses. We discuss implications of these findings for the fundamental physics of glass formation and for effective engineering of protein stabilizing glasses through the modification of s b . ‡

show abstract

“…There are many examples where Weight-Average Molecular Weight and Radius of Gyration of proteins in solution have been characterized by measuring the angular dependence of total scattered intensity (1,7,8,14,15,27,28,33,39). In addition, Dynamic Light Scattering has been used to measure the Hydrodynamic Radius and the size distribution of proteins in solution (2,3,9,11,13,16,17,20,22,34,38,40,43).…”

Section: Application Of Light Scattering For Characterization Of Biommentioning

confidence: 99%

Laser Light Scattering Applications in Biotechnology

Zhelev

Barudov

2005

Biotechnology & Biotechnological Equipment

View full text Add to dashboard Cite

Recent advancement of laser light scattering applications in biotechnology are reviewed with emphasis on their use in the biopharmaceutical industry. Light scattering methods have been used to date to characterize biomolecules in solution. They can provide information about the size and conformation of proteins and their aggregation state as well as their ability to crystallise. In addition, modern light scattering instrumentation is becoming method of choice for studying macromolecular interactions. Interactions between macromolecules such as proteins and nucleic acids mediate fundamental processes and their modulation has led to new strategies for developing therapeutics. Light scattering approaches offer significant advantage to other approaches for studying molecular interactions. Compared with other techniques, light scattering is very quick, uses minimal sample quantities, allows recovery of the sample and does nor require derivatisation.

show abstract

Fractional Stokes−Einstein Relationship in Biological Colloids: Role of Mixed Stick−Slip Boundary Conditions

Cited by 13 publications

References 21 publications

Anomalous Diffusion of Proteins Due to Molecular Crowding

Anomalous Diffusion of Proteins Due to Molecular Crowding

β-Relaxation governs protein stability in sugar-glass matrices

Laser Light Scattering Applications in Biotechnology

Contact Info

Product

Resources

About