•PAP(85-120) peptide forms amyloid fibrils known as SEVI.•Spatial structure of the amyloidogenic PAP(85-120) peptide in aqua solution.•Random coil conformation prevails in the secondary structure of PAP(85-120) peptide.•Proposal, the N- and C-terminuses of PAP(85-120) participate in the fibril formation. Prostatic acid phosphatase (PAP) is an enzyme facilitating infection of cells by HIV. Its peptide fragment PAP(85-120) forms amyloid fibrils known as SEVI, which enhance attachment of the virus by viral adhesion to the host cell prior to receptor-specific binding via reducing the electrostatic repulsion between the membranes of the virus and the target cell. In this work, the PAP(85-120) peptide spatial structure was solved using nuclear magnetic resonance (NMR) spectroscopy and circular dichroism (CD) spectroscopy. The data obtained with the help of NMR (internuclear distances, dihedral angles) allow to calculate the spatial structure of PAP(85-120) using the classical simulated annealing protocol built in XPLOR-NIH. CD spectrum analysis was used to provide the information on the secondary structure of PAP(85-120) that was agreed with the calculated spatial structure. Both methods have shown that the PAP(85-120) characterized by the high flexibility with prevailing random coil structure. The PAP(85-120) peptide structure was compared with the corresponding fragment (85-120 amino acid residues) of the full-length PAP protein (PDB ID 1CVI). The compared peptide structures have turns in the same regions of amino acid residues Q101 and V109, whereas the helix number of the N-terminus and C-terminus is different. Graphical Abstract Display omitted .