Identification and Nanomechanical Characterization of the HIV Tat-Amyloid β Peptide Multifibrillar Structures

HIV transactivator of transcription (Tat) protein could interact with amyloid β (Aβ) peptide which cause the growth of Aβ plaques in the brain and result in Alzheimer's disease in HIV-infected patients. Herein, we employ high-resolution atomic force microscopy and quantitative nanomechanical mapping to investigate the effects of Tat protein in Aβ peptide aggregation. Our results demonstrate that the Tat protein could bind to the Aβ fibril surfaces and result in the formation of Tat-Aβ multifibrillar structures. The resultant Tat-Aβ multifibrillar aggregates represent an increase in stiffness compared with Aβ fibrils due to the increase in β-sheet formation. The identification and characterization of the Tat-Aβ intermediate aggregates is important to understanding the interactions between Tat protein and Aβ peptide, and the development of novel therapeutic strategy for Alzheimer's disease-like disorder in HIV infected individuals.