Radical view of protein damage

Some peptides are more susceptible than others to damage by radicals, according to Helma Wennemers and Matthias Nold from the University of Basel in Switzerland.

Protein damage caused by radicals is blamed for many diseases and for the ageing process, so it is important to understand the processes involved. Wennemers and Nold were particularly keen to determine whether some peptides are damaged more than others. By using a combinatorial library of over 29 000 different tripeptides they were able to analyse which peptide sequences were damaged by radicals generated under Fenton conditions (electron transfer from Fe²⁺ to O₂ or H₂O₂). Their results show that acid-rich peptides are damaged more than other peptides, and that the acid-rich peptides also bind Fe ²⁺ more tightly than other tripeptides. The tight binding means the radicals are formed close to the acid-rich peptides and this causes them to be more susceptible to radical damage.

Caroline Evans