Circular dichroism spectra of α-lactalbumin

Robbins, Frederick M.; Holmes, Leo G.

doi:10.1016/0005-2795(70)90263-1

Cited by 47 publications

(14 citation statements)

References 12 publications

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“…The changes in secondary structure are shown for the central point and the most severe condition (600 MPa, 55°C, 10 min) in Table 3. The data for the untreated sample at pH 7 are consistent with the information obtained by Robbins and Holmes (1970; 25-26% α-helix, 14-15% β-structure, and 60% random structure). There were no evident changes in secondary structure at this pH as the severity of the treatment increased.…”

Section: Far-uv CDsupporting

confidence: 87%

Effects of high hydrostatic pressure on the structure of bovine α-lactalbumin

Rodiles‐López

Arroyo‐Maya

Jaramillo-Flores

et al. 2010

Journal of Dairy Science

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The effects of high hydrostatic pressure (HHP) processing (at 200 to 600 MPa, 25 to 55 degrees C, and from 5 to 15 min) on some structural properties of alpha-lactalbumin was studied in a pH range of 3.0 to 9.0. The range of HHP processes produced a variety of molten globules with differences in their surface hydrophobicity and secondary and tertiary structures. At pH values of 3 and 5, there was a decrease in the alpha-helix content concomitant with an increase in beta-strand content as the pressure increased. No changes in molecular size due to HHP-induced aggregation were detected by sodium dodecyl sulfate-PAGE. All samples showed higher thermostability as the severity of the treatment increased, indicating the formation of a less labile structure related to the HHP treatment.

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Section: Far-uv CDsupporting

confidence: 87%

Effects of high hydrostatic pressure on the structure of bovine α-lactalbumin

Rodiles‐López

Arroyo‐Maya

Jaramillo-Flores

et al. 2010

Journal of Dairy Science

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“…6). The CD at low pH is similar in the far-UV region to that reported earlier (Robbins and Holmes, 1970;Hanssens et at., 1985), but very different in the near-UV region. The absence of near-UV CD in the low-pH region is in keeping with the absence of any stable tertiary structure in the molten globule state.…”

Section: Lo/(lo-1) = L/s< V [Q] "Fa + I/lsupporting

confidence: 75%

Membrane-protein interaction and the molten globule state: Interaction of α-lactalbumin with membranes

1995

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The insertion of soluble proteins into membranes has been a topic of considerable interest. We have studied the insertion of bovine alpha-lactalbumin into single-bilayer vesicles prepared from egg phosphatidylcholine (PC). Fluorescence studies indicated rapid and tight binding of apo-alpha-lactalbumin (apo-alpha-LA) to PC vesicles as a function of pH. The binding was maximal at pH values which favor the formation of the molten globule state. As an increase of hydrophobic surface is observed in the molten globule state, this conformational state can provide a molecular basis for insertion of soluble proteins into membranes. The membrane-bound complex formed at low pH (3.0) could be isolated and was found to be stable at neutral pH. The structural characterization of the apo-alpha-LA-PC complex was studied by fluorescence quenching using iodide, acrylamide, and 9,10-dibromostearic acid. The results obtained indicated that some of the tryptophans of apo-alpha-LA were buried in the membrane interior and some were exposed on the outer side. Fluorescence quenching and CD studies indicated the membrane-bound conformation of apo-alpha-LA was some conformational state that is between the soluble, fully folded conformation and the molten globule state.

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“…with the optical properties of a randomly coiled polypeptide; these figures agree with the lysozyme-based model (258,403). There are differences between a-lactalbumin and lysozyme in their optical rotatory dispersion and circular dichroism spectra, but mainly in the region of absorption caused by aromatic and disulphide chromophores (103), as expected from the differences in amino-acid composition.…”

Section: Secondary and Tertiary Structuresupporting

confidence: 71%