title: SEVI, the semen enhancer of HIV infection along with fragments from its central region, form amyloid fibrils that are toxic to neuronal cells.
abstract: Semen-derived enhancer of viral infection (SEVI) is the term given to the amyloid fibrils formed by a 39-amino acid fragment (PAP248-286) of prostatic acidic phosphatase (PAP) found in human semen. SEVI enhances human immunodeficiency virus (HIV) infectivity by four to five orders of magnitude (Münch et al., 2007). Here, we show by various biophysical techniques including Thioflavin T fluorescence, circular dichroism spectroscopy and transmission electron microscopy that fragments encompassing the central region of SEVI, i.e. PAP248-271 and PAP257-267, form fibrils of similar morphology to SEVI. Our results show that the central region, residues PAP267-271, is crucially important in promoting SEVI fibril formation. Furthermore, SEVI and fibrillar forms of these peptide fragments are toxic to neuronal pheochromocytoma 12 cells but not to epithelial colon carcinoma cells. These findings imply that although SEVI assists in the attachment of HIV-1 to immune cells, it may not facilitate HIV entry by damaging the epithelial cell layer that presents a barrier to the HIV.
authors.affiliation: School of Chemistry and Physics, The University of Adelaide, South Australia 5005, Australia.
authors.forename: Abigail K
authors.initials: AK
authors.lastname: Elias
authors.affiliation: School of Chemistry and Physics, The University of Adelaide, South Australia 5005, Australia.
authors.forename: Denis
authors.initials: D
authors.lastname: Scanlon
authors.affiliation: Discipline of Pharmacology, School of Medical Sciences, The University of Adelaide, South Australia 5005, Australia. Electronic address: ian.musgrave@adelaide.edu.au.
authors.forename: Ian F
authors.initials: IF
authors.lastname: Musgrave
authors.affiliation: Research School of Chemistry, The Australian National University, Australian Capital Territory 0200, Australia. Electronic address: john.carver@anu.edu.au.
authors.forename: John A
authors.initials: JA
authors.lastname: Carver
mesh_terms: D000135:Acid Phosphatase; D020816:Amino Acid Motifs; D000682:Amyloid / Q000737:chemistry* / Q000494:pharmacology; D000818:Animals; D052160:Benzothiazoles; D018938:Caco-2 Cells; D002470:Cell Survival / Q000187:drug effects; D005456:Fluorescent Dyes; D015497:HIV-1 / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D046529:Microscopy, Electron, Transmission; D008969:Molecular Sequence Data; D009928:Organ Specificity; D016716:PC12 Cells; D010446:Peptide Fragments / Q000737:chemistry* / Q000494:pharmacology; D017027:Protein Tyrosine Phosphatases / Q000737:chemistry*; D051381:Rats; D012661:Semen / Q000737:chemistry* / Q000201:enzymology / Q000821:virology; D013050:Spectrometry, Fluorescence; D013844:Thiazoles; D053585:Virus Attachment
chemical_list: D000682:Amyloid; D052160:Benzothiazoles; D005456:Fluorescent Dyes; D010446:Peptide Fragments; D013844:Thiazoles; C009462:thioflavin T; D000135:Acid Phosphatase; C428439:prostatic acid phosphatase; D017027:Protein Tyrosine Phosphatases
keywords: Amyloid fibril; Cell toxicity; HIV; Protein aggregation; SEVI