On the High Viscosity of Aqueous Solution of Lysozyme Induced by Some Organic Solvents

Arêas, Elizabeth Pinheiro Gomes; Arêas, José Alfredo Gomes; Hamburger, James; Peticolas, Warner L.; Santos, Paulo S.

doi:10.1006/jcis.1996.0339

Cited by 29 publications

(66 citation statements)

References 12 publications

(15 reference statements)

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“…1 The results show a nearly constant percentage of H-bond mediated secondary structural elements (70-75%) up to DMSO ) 0.75, while their relative abundance is strongly DMSO dependent: the R-helix content decreases and the -sheet content increases toward DMSO ) 0.75. At higher volume fractions, the summed R-helix and -sheet content decreases, while peak positions deviate from orthodox assignments: only "loose" or "molten" secondary structural elements can be observed as more and more H-bonds between backbone amino acid residues break.…”

Section: Resultsmentioning

confidence: 90%

DMSO-Induced Denaturation of Hen Egg White Lysozyme

et al. 2010

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We report on the size, shape, structure, and interactions of lysozyme in the ternary system lysozyme/DMSO/ water at low protein concentrations. Three structural regimes have been identified, which we term the "folded" (0 < DMSO < 0.7), "unfolded" (0.7 e DMSO < 0.9), and "partially collapsed" (0.9 e DMSO < 1.0) regime. Lysozyme resides in a folded conformation with an average radius of gyration of 1.3 ( 0.1 nm for DMSO < 0.7 and unfolds (average R g of 2.4 ( 0.1 nm) above DMSO > 0.7. This drastic change in the protein's size coincides with a loss of the characteristic tertiary structure. It is preceded by a compaction of the local environment of the tryptophan residues and accompanied by a large increase in the protein's overall flexibility. In terms of secondary structure, there is a gradual loss of R-helix and concomitant increase of -sheet structural elements toward DMSO ) 0.7, while an increase in DMSO at even higher DMSO volume fractions reduces the presence of both R-helix and -sheet secondary structural elements. Protein-protein interactions remain overall repulsive for all values of DMSO . An attempt is made to relate these structural changes to the three most important physical mechanisms that underlie them: the DMSO/water microstructure is strongly dependent on the DMSO volume fraction, DMSO acts as a strong H-bond acceptor, and DMSO is a bad solvent for the protein backbone and a number of relatively polar side groups, but a good solvent for relatively apolar side groups, such as tryptophan.

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Section: Resultsmentioning

confidence: 90%

DMSO-Induced Denaturation of Hen Egg White Lysozyme

et al. 2010

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“…Indications of the physical character of the gels studied in this paper were gathered from previous results on the re- versibility of the protein structure and rheological behavior [10].…”

Section: Discussionmentioning

confidence: 99%

“…The threedimensional structure of such networks is maintained by a collection of cooperative physical contacts of transient character. Protein structure in such gel matrices was found to be considerably altered [10,11,13], although retaining significant amounts of the secondary structure and some globular character [10,13]. The sol-gel physical transition is at least partially reversible, since a very significant recovery of the protein structure and rheological behavior has been verified after removal of the binary organic-aqueous solvent and redispersion of the protein in the original aqueous medium [10].…”

Section: Introductionmentioning

confidence: 97%

“…In particular, we have been interested in the study of lysozyme gelation promoted by certain organic/aqueous binary mixtures, such as tetramethylurea/water and dimethylsulfoxide/water [10][11][12][13], at room temperature. Such processes were shown to generate physical gels, consisting of completely transparent viscoelastic protein matrices.…”

Section: Introductionmentioning

confidence: 99%

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Solvent-induced lysozyme gels: Rheology, fractal analysis, and sol–gel kinetics

Silva

Arêas

2005

Journal of Colloid and Interface Science

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“…A high increase in the protein viscosity was also induced by other organic solvents like tetramethylurea (TMU) [29] and dimethylsulfoxide (DMSO) [29,30]. The pseudoplastic behavior of the protein in TMU indicated that the lysozyme existed in the elongated conformation and was able to reorient under shear stress.…”

Section: Resultsmentioning

confidence: 99%

The SAXS and Rheological Studies of HEWL Amyloid Formation

et al. 2008

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We performed small angle X-ray scattering and rheological experiments in order to analyze the aggregation and denaturation processes of hen egg white lysozyme initiated by the presence of ethanol molecule. At low ethanol concentrations (below 60% (v/v)) we did not observe any change of the radius of gyration of lysozyme and no drastic changes in viscosity of the protein solution. With the increase in ethanol concentration up to the final concentration of 85% (v/v) the viscosity of protein solution dramatically increased. For high ethanol concentration a pseudoplastic behavior of lysozyme solution was observed, indicating a process of aggregation and reorientation of the protein molecules. Similar effects were observed in small angle X-ray scattering experiments. We assume that the analysis of the aggregation processes of the hen egg white lysozyme could contribute to our understanding of the mechanism of lysozyme amyloid formation.

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On the High Viscosity of Aqueous Solution of Lysozyme Induced by Some Organic Solvents

Cited by 29 publications

References 12 publications

DMSO-Induced Denaturation of Hen Egg White Lysozyme

DMSO-Induced Denaturation of Hen Egg White Lysozyme

Solvent-induced lysozyme gels: Rheology, fractal analysis, and sol–gel kinetics

The SAXS and Rheological Studies of HEWL Amyloid Formation

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