Protein Chemistry

An Easy Switch

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Science  08 Jul 2005:
Vol. 309, Issue 5732, pp. 223
DOI: 10.1126/science.309.5732.223a

Protein secondary structure changes from α helices to β sheets appear to play a key role in diseases such as Alzheimer's disease. Metal ions such as Cu2+ and Zn2+ may be partly responsible for these conformational changes. Pagel et al. have now developed a simple peptide model to investigate the influence of metal ions on secondary structure changes.

The authors have designed a peptide that, depending on the solvent, can form either a two-helix dimer or a β-sheet structure. In a modified version of the peptide, histidine residues are incorporated to encourage metal complexation in the β-sheet configuration. The peptides were exposed to Cu or Zn ions, under conditions that normally favor α-helix formation. Whereas the original peptide did not change structure, the histidine- substituted peptide converted to a β-sheet structure. This process could be reversed by introducing a metal scavenger, proving that metal complexation was responsible for the structural change. The system will be useful for systematic studies of the impact of metals on peptide secondary structure. — JFU

Org. Biomol. Chem. 10.1039/b505979h (2005).

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