A highly toxic protein described as the "real bad guy" behind Alzheimer's disease has been identified.
The molecule recruits other less harmful proteins and makes them deadly to brain cells.
Knowing how it forms and behaves is expected to lead to more effective Alzheimer's treatments.
The protein is a special type of beta-amyloid, which was already known to play a key role in Alzheimer's.
Beta-amyloid clumps together in the brains of Alzheimer's patients, forming deposits that result in the destruction of nerve cells.
"This form of beta- amyloid, called pyroglutamylated (or pyroglu) beta-amyloid, is a real bad guy in Alzheimer's disease," said lead scientist Professor George Bloom, from the University of Virginia in the US.
"There are two matters of practical importance in our discovery," he added.
"One is the new insights we have as to how the disease might progress; the other is that it provides a lead into how to design drugs that might prevent this kind of beta-amyloid from building up in the first place."