Abeta produced as a fusion with maltose binding protein can be readily purified and stably associates with copper and zinc

The 42 amino acid Alzheimer's AP peptide has been produced in E. coli as a soluble fusion to maltose binding protein (MBP). Affinity purification on amylose columns of MBP-Ap and MBP led to the recovery of proteins at purities that were suited for physicochemical analyses. MBP-Ap was able to bind approximately 2 mole equivalents of copper or 4 mole equivalents of zinc, while MBP alone bound negligible amounts of zinc or copper. We conclude that AP can bind 2 copper or 4 zinc ions in its fusion format. Because MBP-Ap is a convenient protein to work with, this system is well suited for further studies on the structure of AP and its interactions with metals.