Title

Conformational Prerequisites for α-lconformational Prerequisites for α-lactalbumin Fibrillationactalbumin Fibrillation

Document Type

Article

Publication Date

2002

Keywords

Conformation, Nanofibers, Nucleic Acid Structure, Peptides and Proteins, Ph

Digital Object Identifier (DOI)

https://doi.org/10.1021/bi0262698

Abstract

Bovine α-lactalbumin, a small acidic Ca2+-binding milk protein, formed amyloid fibrils at low pH, where it adopted the classical molten globule-like conformation. Fibrillation was accompanied by a dramatic increase in the β-structure content and a characteristic increase in the thioflavin T fluorescence intensity. S-(Carboxymethyl)-α-lactalbumin, a disordered form of the protein with three out of four disulfide bridges reduced, was even more susceptible to fibrillation. Other partially folded conformations induced in the intact protein at neutral pH, either by the removal of Ca2+ or by the binding of Zn2+ to the Ca2+−protein complex, did not fibrillate, although Zn2+-loaded α-lactalbumin precipitated out of solution as amorphous aggregates. Our data suggest that the transformation of a protein into an essentially unfolded (thus, highly flexible) conformation is required for successful fibril formation, whereas more rigid (but still flexible) species may form amorphous aggregates.

Was this content written or created while at USF?

Yes

Citation / Publisher Attribution

Biochemistry, v. 41, issue 41, p. 12546-12551

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