Infrared and Laser‐raman Spectroscopic Studies of Thermally‐induced Globular Protein Gels

Clark, Allan H.; Saunderson, D.H.P.; Suggett, A.

doi:10.1111/j.1399-3011.1981.tb02002.x

Cited by 270 publications

(83 citation statements)

References 26 publications

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“…2c). This is in agreement with previous reports which showed that antiparallel b-sheets were formed when BSA was heated above 65°C and that aggregates were formed through the hydrogen bonding of b-sheets between monomers [45][46][47][48]. Our results suggest that nicotine can slow down the formation of these b-sheets in glycated proteins.…”

Section: Discussionsupporting

confidence: 95%

Nicotine Reduces the Cytotoxic Effect of Glycated Proteins on Microglial Cells

2009

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Protein glycation has been implicated to play an important role in the pathogenesis of Alzheimer's disease and other neurological disorders. Glycation induces extensive change in the structure of proteins and leads to the formation of cross beta-structures which are detected by the receptor of AGE. Activation of these receptors by glycated proteins transduces the signaling pathways which contribute to neuronal malfunctions and death. Glycated proteins can induce activation of microglia, which exacerbate the pathology of Alzheimer's disease by causing chronic inflammation. Compounds which can decelerate glycation or prevent the structural change of proteins during glycation should be of therapeutic interest. In this study the effect of nicotine on protein glycation and structural alterations of the glycated protein were investigated. Bovine serum albumin, as a model protein, was glycated by glucose in the presence or absence of nicotine and structural changes in the protein together with the effect of glycated proteins on the activation of microglia via receptor of AGE were studied. Nicotine not only could not prevent glycation, but even increased protein glycation. However, proteins glycated in the presence of nicotine did not form beta-structures. In the absence of this secondary structure glycated proteins cannot bind to the receptor of AGE on microglia. Here we showed that glycated proteins prepared in the presence of nicotine could not activate microglial cells.

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Section: Discussionsupporting

confidence: 95%

Nicotine Reduces the Cytotoxic Effect of Glycated Proteins on Microglial Cells

2009

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“…The first and the fourth components are indicative of cross-b and antiparallel b-sheet structures, respectively. [30][31][32] The component at 1650 cm 21 is usually assigned to unordered conformations since the a-helical structure is very unlikely for these polypeptides, while residual water can eventually contribute in this region. 33 The component at 1674 cm 21 can be assigned to PPII together with b-turn conformations.…”

Section: Ftir Spectra Of Precipitatesmentioning

confidence: 99%

Influence of amino acid specificities on the molecular and supramolecular organization of glycine‐rich elastin‐like polypeptides in water

et al. 2011

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Elastin-like polypeptides adopt complex supramolecular structures, showing either a hydrophobic or a hydrophilic surface, depending on their surrounding environment and the supporting substrate. The preferred organization is important in many situations ranging from biocompatibility to bio-function. Here we compare the n-repeat pentamer LeuGlyGlyValGly (n = 7) with the analogue ValGlyGlyValGly (n = 5), as water suspensions and as deposits on silicon substrates. These sequences contain the repeat XxxGlyGlyZzzGly (Xxx, Zzz = Val, Leu) motif belonging to the hydrophobic glycine-rich domain of elastin and represent a simplified model from which to obtain information on molecular interactions functional to elastin itself. The compounds studied differ only by the presence of the -CH(2)- spacer in the Leu moiety and thus the work was aimed at revealing the influence of this spacer element on self assembly. Both polypeptides were studied under identical conditions, using combined techniques, to identify differences in their conformational states both at molecular (CD, FTIR) and supramolecular (XPS, AFM) levels. By these means, together with a Congo Red spectroscopic assay of β-sheet formation in water, a clear correlation between amino acid sequences (sequence specificity) and their kinetics and ordering of aggregation has emerged. The novel outcomes of this work are from the supplementary measurements, made to augment the AFM and XPS studies, showing that the significant step in the self assembly of both polypeptides takes place in the liquid phase and from the finding that the substitution of Val by Leu in the first position of the pentapeptide effectively inhibits the formation of amyloidal fibers.

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“…Heating causes increased ␤-structure formation and gelation for BSA (Clark et al 1981b), lysozyme (Clark et al 1981b), and myoglobin (Dong et al 2000;Meersman et al 2002). TEM characterization of protein gels has revealed a range of structures, including networks of fibrils (Clark et al 1981a;Kavanagh et al 2000).…”

Section: Mechanisms Of Sonication-induced Protein Aggregationmentioning

confidence: 99%

Sonication of proteins causes formation of aggregates that resemble amyloid

et al. 2004

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Despite the widespread use of sonication in medicine, industry, and research, the effects of sonication on proteins remain poorly characterized. We report that sonication of a range of structurally diverse proteins results in the formation of aggregates that have similarities to amyloid aggregates. The formation of amyloid is associated with, and has been implicated in, causing of a wide range of protein conformational disorders including Alzheimer's disease, Huntington's disease, Parkinson's disease, and prion diseases. The aggregates cause large enhancements in fluorescence of the dye thioflavin T, exhibit green-gold birefringence upon binding the dye Congo red, and cause a red-shift in the absorbance spectrum of Congo red. In addition, circular dichroism reveals that sonication-induced aggregates have high ␤-content, and proteins with significant native ␣-helical structure show increased ␤-structure in the aggregates. Ultrastructural analysis by electron microscopy reveals a range of morphologies for the sonication-induced aggregates, including fibrils with diameters of 5-20 nm. The addition of preformed aggregates to unsonicated protein solutions results in accelerated and enhanced formation of additional aggregates upon heating. The dye-binding and structural characteristics, as well as the ability of the sonication-induced aggregates to seed the formation of new aggregates are all similar to the properties of amyloid. These results have important implications for the use of sonication in food, biotechnological and medical applications, and for research on protein aggregation and conformational disorders.

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Infrared and Laser‐raman Spectroscopic Studies of Thermally‐induced Globular Protein Gels

Cited by 270 publications

References 26 publications

Nicotine Reduces the Cytotoxic Effect of Glycated Proteins on Microglial Cells

Nicotine Reduces the Cytotoxic Effect of Glycated Proteins on Microglial Cells

Influence of amino acid specificities on the molecular and supramolecular organization of glycine‐rich elastin‐like polypeptides in water

Sonication of proteins causes formation of aggregates that resemble amyloid

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