Complexation between Cu(II) and curcumin in the presence of two different segments of amyloid β

Angela L. Picciano, Timothy D. Vaden

    Research output: Contribution to journalArticlepeer-review

    21 Scopus citations

    Abstract

    The natural product curcumin has been shown to play a role in preventing Aβ amyloid fibril formation. This role could include chelation of transition metal ions such as Cu2 +, known to accelerate amyloid aggregation, and/or curcumin-binding directly to the Aβ protein. To investigate these different roles, curcumin complexation to Cu2 + was investigated in the presence and absence of two different segments of the Aβ protein including the copper-binding (Aβ6-14) and curcumin-binding (Aβ14-23) domains. Absorbance and fluorescence spectroscopy in 90% water/10% methanol solutions showed that curcumin can bind Cu2 + to some extent in the presence of both segments despite strong peptide-ion interactions. Estimated Cu2 +-curcumin binding affinities in the absence (1.6 × 105 M- 1) and presence (7.9 × 104 M- 1) of the peptide provide quantitative support for this Cu2 + chelation role. With the Aβ14-23 segment, the curcumin simultaneously binds to Cu2 + and the peptide, demonstrating that it can play multiple roles in the prevention of amyloid formation. The stabilities of ternary peptide-Cu2 +-curcumin complexes were evaluated using ESI mass spectrometry and support the conclusion that curcumin can act as a weak metal ion chelator and also bind directly to the Aβ14-23 peptide segment.

    Original languageEnglish (US)
    Pages (from-to)62-67
    Number of pages6
    JournalBiophysical Chemistry
    Volume184
    DOIs
    StatePublished - Jan 1 2013

    All Science Journal Classification (ASJC) codes

    • Biophysics
    • Biochemistry
    • Organic Chemistry

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