Self-assembly and secondary structure of beta-casein

Faizullin, Dzhigangir A.; Konnova, Tatiana A.; Haertlé, Thomas; Zuev, Yu. F.

doi:10.1134/s1068162013040067

Cited by 24 publications

(14 citation statements)

References 24 publications

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“…3a). This same behavior was observed by Faizullin, Konnova, Haertle, and Zuev (2013), studying β-casein at similar increasing temperature conditions. At 75°C, the system at pH 3.5 had more intense negative peaks than the system at pH 6.5, similar to results observed by Naqvi, Ahmad, Khan, and Saleemuddin (2013) studying β-lactoglobulin, which displayed higher negative molar ellipticity at pH 2.0 compared to pH 7.0 and 9.0.…”

Section: Circular Dichroismsupporting

confidence: 84%

Production, characterization and foamability of α-lactalbumin/glycomacropeptide supramolecular structures

Diniz¹,

Coimbra²,

Teixeira³

et al. 2014

Food Research International

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The study of protein interactions has generated great interest in the food industry. Therefore, research on new supramolecular structures shows promise. Supramolecular structures of the whey proteins α-lactalbumin and glycomacropeptide were produced under varying heat treatments (25 to 75°C) and acidic conditions (pH3.5 to 6.5). Isothermal titration calorimetry experiments showed protein interactions and demonstrated that this is an enthalpically driven process. Supramolecular protein structures in aqueous solutions were characterized by circular dichroism and intrinsic fluorescence spectroscopy. Additional photon correlation spectroscopy experiments showed that the size distribution of the structures ranged from 4 to 3545nm among the different conditions. At higher temperatures, lower pH increased particle size. The foamability of the supramolecular protein structures was evaluated. Analysis of variance and analysis of regression for foaming properties indicated that the two-factor interactions between pH and temperature exhibited a significant effect on the volume and stability of the foam.

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Section: Circular Dichroismsupporting

confidence: 84%

Production, characterization and foamability of α-lactalbumin/glycomacropeptide supramolecular structures

Diniz¹,

Coimbra²,

Teixeira³

et al. 2014

Food Research International

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“…As well as confirming that A 1 β-CN forms larger micelles above the CMC, DLS was used to examine changes in micelle size with increasing temperature. The A 1 and A 2 variants showed very similar trends above the CMC, with both variants increasing in size in a temperature range of 30 to 40°C ( Figure 2B), which has been observed by others (O'Connell et al, 2003;Faizullin et al, 2013); A 1 β-CN again maintained a larger micelle size throughout the increase in temperature.…”

Section: A 2supporting

confidence: 73%

Structural differences between bovine A1 and A2 β-casein alter micelle self-assembly and influence molecular chaperone activity

Raynes

Day

Augustin

et al. 2015

Journal of Dairy Science

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Within each milk protein there are many individual protein variants and marked alterations to milk functionality can occur depending on the genetic variants of each protein present. Bovine A(1) and A(2) β-casein (β-CN) are 2 variants that contribute to differences in the gelation performance of milk. The A(1) and A(2) β-CN variants differ by a single AA, the substitution of histidine for proline at position 67. β-Casein not only participates in formation of the casein micelle but also forms an oligomeric micelle itself and functions as a molecular chaperone to prevent the aggregation of a wide range of proteins, including the other caseins. Micelle assembly of A(1) and A(2) β-CN was investigated using dynamic light scattering and small-angle X-ray scattering, whereas protein functionality was assessed using fluorescence techniques and molecular chaperone assays. The A(2) β-CN variant formed smaller micelles than A(1) β-CN, with the monomer-micelle equilibrium of A(2) β-CN being shifted toward the monomer. This shift most likely arose from structural differences between the 2 β-CN variants associated with the adoption of greater polyproline-II helix in A(2) β-CN and most likely led to enhanced chaperone activity of A(2) β-CN compared with A(1) β-CN. The difference in micelle assembly, and hence chaperone activity, may provide explain differences in the functionality of homozygous A(1) and A(2) milk. The results of this study highlight that substitution of even a single AA can significantly alter the properties of an intrinsically unstructured protein such as β-CN and, in this case, may have an effect on the functionality of milk.

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“…6a), which may indicate that heat treatment promoted significant changes in a-helices of a-La and Lys (Jindal & Naeem, 2013). This behavior was observed by Faizullin, Konnova, Haertle and Zuev (2013) for b-casein (0.5 mg mL À1 ) when heated from 10 to 60 C, and is in agreement with results reported by Zhang and Zhong (2012) who verified that increasing the heating temperature of bovine serum albumin (0.6 mg mL À1 ) and a-La (0.7 mg mL À1 ) up to 85 C reduce the intensity of the negative peaks in CD spectra, as a result of the decreased content of a-helical structure obtained for both proteins, thus indicating that the secondary structure changed. These results suggest that 75 C and pH 11 are critical conditions to promote changes in a-La and Lys secondary structures during protein assembling.…”

Section: Circular Dichroismmentioning

confidence: 79%

Design of bio-based supramolecular structures through self-assembly of α-lactalbumin and lysozyme

Monteiro

Pereira

et al. 2016

Food Hydrocolloids

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Bovine a-lactalbumin (a-La) and lysozyme (Lys), two globular proteins with highly homologous tertiary structures and opposite isoelectric points, were used to produce bio-based supramolecular structures under various pH values (3, 7 and 11), temperatures (25, 50 and 75 C) and times (15, 25 and 35 min) of heating. Isothermal titration calorimetry experiments showed protein interactions and demonstrated that structures were obtained from the mixture of a-La/Lys in molar ratio of 0.546. Structures were characterized in terms of morphology by transmission electron microscopy (TEM) and dynamic light scattering (DLS), conformational structure by circular dichroism and intrinsic fluorescence spectroscopy and stability by DLS. Results have shown that protein conformational structure and intermolecular interactions are controlled by the physicochemical conditions applied. The increase of heating temperature led to a significant decrease in size and polydispersity (PDI) of a-LaeLys supramolecular structures, while the increase of heating time, particularly at temperatures above 50 C, promoted a significant increase in size and PDI. At pH 7 supramolecular structures were obtained at microscale e confirmed by optical microscopy e displaying also a high PDI (i.e. > 0.4). The minimum size and PDI (61 ± 2.3 nm and 0.14 ± 0.03, respectively) were produced at pH 11 for a heating treatment of 75 C for 15 min, thus suggesting that these conditions could be considered as critical for supramolecular structure formation. Its size and morphology were confirmed by TEM showing a well-defined spherical form. Structures at these conditions showed to be stable at least for 30 or 90 days, when stored at 25 or 4 C, respectively. Hence, a-LaeLys supramolecular structures showed properties that indicate that they are a promising delivery system for food and pharmaceutical applications.

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Self-assembly and secondary structure of beta-casein

Cited by 24 publications

References 24 publications

Production, characterization and foamability of α-lactalbumin/glycomacropeptide supramolecular structures

Production, characterization and foamability of α-lactalbumin/glycomacropeptide supramolecular structures

Structural differences between bovine A1 and A2 β-casein alter micelle self-assembly and influence molecular chaperone activity

Design of bio-based supramolecular structures through self-assembly of α-lactalbumin and lysozyme

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