Tuning the properties of β-lactoglobulin nanofibrils with pH, NaCl and CaCl2

Self-assembly of proteins into amyloid-like nanofibrils is not only a key event in several diseases, but such fibrils are also associated with intriguing biological function and constitute promising components for new biobased materials. The bovine whey protein b-lactoglobulin has emerged as an important model protein for the development of such materials. We here report that peptide hydrolysis is the rate-determining step for fibrillation of b-lactoglobulin in whey protein isolate. We also explore the observation that blactoglobulin nanofibrils of distinct morphologies are obtained by simply changing the initial protein concentration. We find that the morphological switch is related to different nucleation mechanisms and that the two classes of nanofibrils are associated with variations of the peptide building blocks. Based on the results, we propose that the balance between protein concentration and the hydrolysis rate determines the structure of the formed nanofibrils.

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“…7, 21, 29, 32 and 33). The curved brils resemble those reported with altered solution conditions 7,8,29,34 or at high initial concentration.…”

Section: -19supporting

confidence: 76%

On the role of peptide hydrolysis for fibrillation kinetics and amyloid fibril morphology

Hedenqvist

Langton

et al. 2018

RSC Adv.

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“…Often, β-lg fibrils are created at pH 2 and low ionic strength by heating at 80 C. Loveday et al (2010) observed that when β-lg adjusted to pH 1.6-2.4 was heated at 80 C, the morphology of the resulting fibrils was little affected by pH, but fibrils formed faster at pH < 2. Thioflavin T (ThT) fluorescence increased sigmoidally with heating time; fluorescence changed little for the first few hours (lag phase), then increased rapidly (growth phase) and finally plateaued (stationary phase).…”

Section: Resultsmentioning

confidence: 99%

“…From transmission electron microscope images of the fibrils, the calculated persistence lengths of the fibrils were found to decrease with the addition of NaCl (Loveday et al 2011a(Loveday et al , 2010.…”

Section: Resultsmentioning

confidence: 99%

“…The differences in the values of G 0 inf of the gels are likely due to differences in the characteristics of the fibrils: l p , L c , and filament density n (filaments m À3 ). Data on these variables were not available for fibrils made by incubation in solvents, but l p and L c were reported for heat-induced fibrils in some studies (Loveday et al 2010). We recently investigated the effect of CaCl 2 on G 0 inf for fibrils made by heating 10 % w/w whey protein isolate at pH 2 and 80 C (Loveday et al 2011c).…”

Section: Resultsmentioning

confidence: 99%

“…We recently investigated the effect of CaCl 2 on G 0 inf for fibrils made by heating 10 % w/w whey protein isolate at pH 2 and 80 C (Loveday et al 2011c). Adding 40-80 mM CaCl 2 decreased l p (Loveday et al 2010) but increased G 0 inf (Loveday et al 2011c). The increased fibril flexibility (lower l p ) resulting from the presence of CaCl 2 apparently allowed fibrils to entangle better, forming a stronger network.…”

Section: Resultsmentioning

confidence: 99%

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