Analysis of protein–surfactant interactions—a titration calorimetric and fluorescence spectroscopic investigation of interactions between Humicola insolens cutinase and an anionic surfactant

Nielsen, Anders Dybdal; Arleth, Lise; Westh, Peter

doi:10.1016/j.bbapap.2005.08.001

Cited by 83 publications

(95 citation statements)

References 26 publications

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“…This behavior has been observed for other proteins [23,24,41] and ascribed to the completion of the surfactant adsorption process. This saturation is governed by the appearance of micelles in the aqueous bulk (see below) and thus essentially reflects an "apparent CMC" in the presence of the protein.…”

Section: Accepted M Manuscriptsupporting

confidence: 64%

“…Together with a few other examples [12,[22][23][24] . These determinations of secondary structure contents were based on a protein reference set from the soft ware package CDPro [35].…”

Section: Discussionmentioning

confidence: 99%

“…Thus, the concentration of SDS in the calorimetric cell is raised to CMC and additional micelles will not be dissolved; c.f. [23,39]. The CMC value of SDS in the protein free solution is best described by the inflexion point of this part of the curve [39].…”

Section: Accepted M Manuscriptmentioning

confidence: 99%

“…More quantitative data may be derived from the ITC results by applying a simple partitioning model which considers the equilibrium between dissolved (free) and protein bound detergent [23]. …”

Section: Accepted M Manuscriptmentioning

confidence: 99%

“…Glucose oxidase, for example, binds very little SDS and (in a certain pH range) retains its catalytic activity at high SDS [12,22]. Also, we have recently found that the lipolytic enzyme cutinase binds only about 0.4 g SDS/ g at saturation [23,24].…”

mentioning

confidence: 99%

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Glycoprotein-surfactant interactions: A calorimetric and spectroscopic investigation of the phytase-SDS system

Bagger

Hoffmann

Fuglsang

et al. 2007

Biophysical Chemistry

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This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT2 AbstractThe interactions of sodium dodecyl sulfate (SDS) and two glyco-variants of the enzyme phytase from Peniophora lycii were investigated. One variant (Phy) was heavily glycosylated while the other (dgPhy) was enzymatically deglycosylated. Effects at 24°C of titrating SDS to Phy and dgPhy were studied by Isothermal Titration Calorimetry (ITC) and Synchrotron Radiation Circular Dichroism (SRCD) spectroscopy. Comparisons of results for the two variants were used to elucidate glycan-surfactant interrelationships.The CD spectra suggested that both the native and the SDS-denatured states of the two variants were mutually similar, and hence that the denaturation process was structurally equivalent for the two glyco-variants.The denatured state was far from fully unfolded and probably retained a substantial content of native-like structure. Furthermore, it was found that the glycans brought about only a small increase in the resistance towards SDS induced denaturation. The SDS concentration required to denature half of the protein molecules differed less than 1 mM for the two variants.The affinity for SDS of both variants was unusually low. The amount of bound SDS (w/w) at different stages of the binding isotherm was 3-10 times lower than that reported for the most previously investigated globular proteins. Analysis of the relative affinity of the glycan and peptide moieties suggested that the carbohydrates bind much less surfactant. At saturation, glycans adsorbed about half as much SDS (in g/g) as the peptide moiety of Phy and about five times less than average proteins.

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Section: Accepted M Manuscriptsupporting

confidence: 64%

“…Together with a few other examples [12,[22][23][24] . These determinations of secondary structure contents were based on a protein reference set from the soft ware package CDPro [35].…”

Section: Discussionmentioning

confidence: 99%

Section: Accepted M Manuscriptmentioning

confidence: 99%

Section: Accepted M Manuscriptmentioning

confidence: 99%

mentioning

confidence: 99%

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Glycoprotein-surfactant interactions: A calorimetric and spectroscopic investigation of the phytase-SDS system

Bagger

Hoffmann

Fuglsang

et al. 2007

Biophysical Chemistry

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Surfactants and Alcohols as Inducers of Protein Amyloid: Aggregation Chaperones or Membrane Simulators?

Otzen

2011

Lipids and Cellular Membranes in Amyloid Diseases

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Stable intermediates determine proteins' primary unfolding sites in the presence of surfactants

et al. 2008

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Despite detailed knowledge of the overall structural changes and stoichiometries of surfactant binding, little is known about which protein regions constitute the preferred sites of attack for initial unfolding. Here we have exposed three proteins to limited proteolysis at anionic (SDS) and cationic (DTAC) surfactant concentrations corresponding to specific conformational transitions, using the surfactant-robust broad-specificity proteases Savinase and Alcalase. Cleavage sites are identified by SDS-PAGE and N-terminal sequencing. We observe well-defined cleavage fragments, which suggest that flexibility is limited to certain regions of the protein. Cleavage sites for alpha-lactalbumin and myoglobin correspond to regions identified in other studies as partially unfolded at low pH or in the presence of organic solvents. For Tnfn3, which does not form partially folded structures under other conditions, cleavage sites can be rationalized from the structure of the protein's folding transition state and the position of loops in the native state. Nevertheless, they are more sensitive to choice of surfactant and protease, probably reflecting a heterogeneous and fluctuating ensemble of partially unfolded structures. Thus, for proteins accumulating stable intermediates on the folding pathway, surfactants encourage the formation of these states, while the situation is more complex for proteins that do not form these intermediates.

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Analysis of protein–surfactant interactions—a titration calorimetric and fluorescence spectroscopic investigation of interactions between Humicola insolens cutinase and an anionic surfactant

Cited by 83 publications

References 26 publications

Glycoprotein-surfactant interactions: A calorimetric and spectroscopic investigation of the phytase-SDS system

Glycoprotein-surfactant interactions: A calorimetric and spectroscopic investigation of the phytase-SDS system

Surfactants and Alcohols as Inducers of Protein Amyloid: Aggregation Chaperones or Membrane Simulators?

Stable intermediates determine proteins' primary unfolding sites in the presence of surfactants

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