Study of thermal denaturation of lysozyme and other globular proteins by light‐scattering spectroscopy

Nicoli, D. F.; Benedek, George B.

doi:10.1002/bip.1976.360151209

Cited by 107 publications

(64 citation statements)

References 35 publications

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“…It follows from our measurements that for lysozyme in aqueous solution with zero concentration of ethanol the value of the hydrodynamic radius equals (1.856 ± 0.023) nm, which is in a good agreement with the results known from literature (e.g. 1.811 nm [22], 1.85 nm [25], 1.87 nm [24], 1.96 nm [27]). When the ethanol concentration reaches 9.91% (v/v), hydrodynamic radius increases up to (2.277 ± 0.020) nm.…”

Section: Resultssupporting

confidence: 92%

“…The change of the B 22 value is independent of NaCl concentration, which means that presence of ethanol molecules does not aect electrostatic proteinprotein interaction. Changes of the diusion coecient, presented above, could be attributed to the increasing viscosity of the solvent, as it was in the waterglycerol solutions [24] or to the denaturation process, as it was observed in the case of temperature denaturation [25] and chemical denaturation by guanidine hydrochloride (Gdn · HCl) [26]. Since the viscosity of waterethanol solution changes from 1.05 × 10 (for 10.6% EtOH (v/v)) [16], we assume that the observed changes are connected with the structural transformations of the protein molecule related to its dehydration.…”

Section: Resultsmentioning

confidence: 80%

“…In general, the denaturation process is described as a cooperative two-state transition from folded to unfolded state. As a consequence of thermal denaturation the diffusion coecient decreases and the hydrodynamic radius of the protein increases by approximately 18% [25]. In the case of chemical denaturation, when the concentration of Gdn · HCl increases from 0 to about 2 M, the diusion coecient of lysozyme remains constant and equals (1.06 ± 0.01) × 10 −10 m 2 /s [26].…”

Section: Resultsmentioning

confidence: 99%

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Light Scattering Studies of Hydration and Structural Transformations of Lysozyme

Szymańska

Ślósarek

2012

Acta Phys. Pol. A

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We have applied the method of dynamic light scattering to analyse the lysozymeethanol interaction. For low ethanol concentration (below 4.3% (v/v)) no chemical denaturation process is observed. When the ethanol concentration grows above the triggering concentration the hydrodynamic radius of lysozyme increases, indicating the structural changes within the protein molecule. The observed structural modications are attributed to dehydration and preliminary tertiary structure modication of the protein molecule.

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Section: Resultssupporting

confidence: 92%

Section: Resultsmentioning

confidence: 80%

Section: Resultsmentioning

confidence: 99%

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Light Scattering Studies of Hydration and Structural Transformations of Lysozyme

Szymańska

Ślósarek

2012

Acta Phys. Pol. A

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“…42 The overall repulsive character of the protein-protein interactions and the low lysozyme concentrations, C LYS < 10 g L -1 , explain why The self-diffusion coefficient, D 0 , was calculated from literature values of the hydrodynamic radius, R h of (0) the native protein for 0 e DMSO e 1 and of (O) the native protein for 0 e DMSO e 0.6 (R h ) 1.87) and the denatured protein for 0.7 e DMSO e 1.0 (R h ∼ 2.75). 37,41,43 54. We assume that lysozyme has 193 exchangeable protons in the folded states and 263 exchangeable protons in the unfolded states.…”

Section: Resultsmentioning

confidence: 99%

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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“…Nicoli and Benedek [38] found that the heat denaturation of lysozyme increases the hydrodynamic radius from 1.85 nm to 2.18 nm and not to the 4.9 nm calculated for a random coil. Our results for sepia cartilage collagen suggest that hydrodynamic volume (rather hydrodynamic radius) increases with the increase in temperature below the denaturation temperature of collagen.…”

Section: Hydrated Volume and Interaction Of Surfactant With Collagenmentioning

confidence: 96%

Physico‐chemical studies of micelle formation on sepia cartilage collagen solutions in acetate buffer and its interaction with ionic and nonionic micelles

Mandal

Ramesh

Dhar

1987

European Journal of Biochemistry

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Sepia cartilage collagen (pepsin-extracted) in acetate buffer (pH = 2.98) forms micelles at a particular concentration below which they do not normally form. The critical micelle concentration (cmc) of the collagen was determined in buffer as well as in SDS, cetyltrimethylammonium bromide (CTAB) and Tween-80 micellar environments at different temperatures. Mutual interaction of collagen micelles with the ionic and nonionic micelles through the formation of the mixed micelle concept has also been found. The cmc of collagen decreased in the presence of SDS and Tween-80 micelles whereas it increased in the presence of CTAB micelles. This clearly suggests that the micelle formation of collagen is facilitated by the presence of SDS and Tween-80 and hindered by CTAB micelles. The various thermodynamic parameters were estimated from viscosity measurements and the transfer of collagen into the micelles of various surfactants and the reverse phenomenon was analyzed. This analysis has also been modelled conceptually as a different phase and the results have supported the above phenomenon. Our thermodynamic results are also able to predict the exact denaturation temperature as well as the structural order of water in the collagen in various environments. The hydrated volumes, Vh, of collagen in the above environments and intrinsic viscosity were also calculated. The low intrinsic viscosity, [?I, of collagen in an SDS environment compared to buffer and other surfactant environments suggested more workable systems in cosmetic and dermatological skin care preparations. The one and two-hydrogen-bonded models of this collagen in various environments have been analyzed. The calculated thermodynamic parameters varied with the concentration of collagen. The change of thermodynamic parameters from coil-coil to random-coil conformation upon denaturation of collagen were calculated from the amount of proline and hydroxyproline residues and compared with viscometric results. Thermodynamic results suggest that the stability of the collagen in the additive environments is in the following order: SDS > Tween-80 > buffer > CTAB.It is well known that the structure of water is important for interactions between proteins and membrane transport phenomena. These interactions are difficult to study due to the fact that the exact shapes, sizes and structure of the proteins are not clearly known. A favourable exception is collagen, consisting of triple-stranded helices which can be regarded as rigid rods. According to X-ray diffraction patterns the rods are packed in a complex lattice [l]. The important features are that the rods are aligned along the fiber axis and that the lattice expands [2] commensurate with the water content. The studies from various sources have indicated that the structure of water absorbed in collagen is different from that of water in bulk. Broad-line NMR measurements [3 -61 have shown two absorption lines instead of one. This may be the reason that the water molecules in collagen do not rotating isotropically. Moreover,...

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Study of thermal denaturation of lysozyme and other globular proteins by light‐scattering spectroscopy

Cited by 107 publications

References 35 publications

Light Scattering Studies of Hydration and Structural Transformations of Lysozyme

Light Scattering Studies of Hydration and Structural Transformations of Lysozyme

DMSO-Induced Denaturation of Hen Egg White Lysozyme

Physico‐chemical studies of micelle formation on sepia cartilage collagen solutions in acetate buffer and its interaction with ionic and nonionic micelles

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