Protein engineering to stabilize soluble amyloid β-protein aggregates for structural and functional studies

Area of Science:

• Neuroscience
• Molecular Biology
• Biochemistry

Background:

• Alzheimer's disease (AD) pathogenesis involves amyloid-beta (Aβ) protein aggregation and neuronal death.
• Small, soluble Aβ aggregates (oligomers, protofibrils) are key neurotoxic species, but their study is challenging due to instability and heterogeneity.
• Understanding the structure and function of these toxic Aβ species is crucial for AD research.

Purpose of the Study:

• To review the application of protein engineering, specifically disulfide engineering, in stabilizing and characterizing Aβ aggregates.
• To highlight how stabilized Aβ aggregates aid in understanding their neurotoxic mechanisms and structural properties relevant to Alzheimer's disease.
• To demonstrate protein engineering as a viable strategy for investigating Aβ oligomers and protofibrils.

Main Methods:

• Utilizing protein engineering, particularly disulfide engineering, to create stabilized forms of Aβ aggregates.
• Generating stable, neurotoxic protofibrillar forms of Aβ.
• Creating engineered Aβ dimers and larger aggregates.

Main Results:

• Stable and neurotoxic protofibrillar forms of Aβ have been successfully obtained.
• Engineered Aβ dimers and aggregates induce specific neuronal damage mirroring Alzheimer's disease pathology.
• Disulfide engineering revealed that Aβ in toxic aggregates adopts a distinct β-hairpin conformation compared to mature amyloid fibrils.

Conclusions:

• Protein engineering, especially disulfide engineering, is an effective strategy for stabilizing and studying neurotoxic Aβ aggregates.
• Stabilized Aβ aggregates provide insights into the structural basis of neurotoxicity in Alzheimer's disease.
• This approach facilitates research into the structure, interconversion, and biological effects of Aβ oligomers and protofibrils.