Chemists have synthesized a protein fragment that, in test-tube studies, disrupts the formation of the fiber networks suspected to be a cause of Alzheimer's disease.
In the brains of Alzheimer's patients, a protein called beta-amyloid assembles into fibers, which clump together to create networks of fibers called plaques. In the first step toward this fiber formation, the stringlike proteins bind along their sub-nanometer lengths, says Robert P. Hammer of Louisiana State University in Baton Rouge. The resulting sheets of protein organize into micrometer-scale fibers.
Hammer's team focused on a set of five amino acids in the middle of the beta-amyloid, which has a total length of 40 amino acids. The scientists synthesized a protein fragment, or peptide, that mimicked this set, but they tweaked certain chemical groups that normally enable beta-amyloid proteins to bind. The idea was to create a peptide that would "interrupt or change the assembly of beta-amyloid protein,"