title: Prion fragment peptides are digested with membrane type matrix metalloproteinases and acquire enzyme resistance through Cu²⁺-binding.
abstract: Prions are the cause of neurodegenerative disease in humans and other mammals. The structural conversion of the prion protein (PrP) from a normal cellular protein (PrPC) to a protease-resistant isoform (PrPSc) is thought to relate to Cu2+ binding to histidine residues. In this study, we focused on the membrane-type matrix metalloproteinases (MT-MMPs) such as MT1-MMP and MT3-MMP, which are expressed in the brain as PrPC-degrading proteases. We synthesized 21 prion fragment peptides. Each purified peptide was individually incubated with recombinant MT1-MMP or MT3-MMP in the presence or absence of Cu2+ and the cleavage sites determined by LC-ESI-MS analysis. Recombinant MMP-7 and human serum (HS) were also tested as control. hPrP61-90, from the octapeptide-repeat region, was cleaved by HS but not by the MMPs tested here. On the other hand, hPrP92-168 from the central region was cleaved by MT1-MMP and MT3-MMP at various sites. These cleavages were inhibited by treatment with Cu2+. The C-terminal peptides had higher resistance than the central region. The data obtained from this study suggest that MT-MMPs expressed in the brain might possess PrPC-degrading activity.
authors: Analytical Chemistry, Pharmaceutical Science, Setsunan University, 45-1 Nagaotoge-cho, Hirakata, Osaka 573-0101, Japan. ayak@ims.u-tokyo.ac.jp.
authors: Aya
authors: A
authors: Kojima
authors: Analytical Chemistry, Pharmaceutical Science, Setsunan University, 45-1 Nagaotoge-cho, Hirakata, Osaka 573-0101, Japan. motomi@pharm.setsunan.ac.jp.
authors: Motomi
authors: M
authors: Konishi
authors: Analytical Chemistry, Pharmaceutical Science, Setsunan University, 45-1 Nagaotoge-cho, Hirakata, Osaka 573-0101, Japan. akizawa@pharm.setsunan.ac.jp.
authors: Toshifumi
authors: T
authors: Akizawa
mesh_terms: D000595:Amino Acid Sequence; D001921:Brain / Q000378:metabolism; D003300:Copper / Q000378:metabolism*; D006801:Humans; D053504:Matrix Metalloproteinases, Membrane-Associated / Q000378:metabolism*; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism*; D018621:PrPC Proteins / Q000737:chemistry*; D011485:Protein Binding; D059748:Proteolysis
chemical_list: D010446:Peptide Fragments; D018621:PrPC Proteins; D003300:Copper; D053504:Matrix Metalloproteinases, Membrane-Associated