title: Structure of the active 27-residue fragment of human calpastatin.
abstract: A synthetic 27-residue peptide corresponding to exon 1B of the endogenous inhibitor calpastatin contains a well-conserved region and has an ability to inhibit the cysteine endopeptidase calpain specifically. We examined the solution structure of this peptide in DMSO-d6 by two-dimensional 1H NMR spectroscopy. Although regular secondary structures such as alpha-helix and beta-sheet were not found, the region from Ile18 to Arg23 formed a well-defined structure with a type I beta-turn. This region coincided well with the highly conserved region of calpastatin. The result strongly suggests that this turn structure is essential for the inhibitory activity of calpastatin.
authors.affiliation: Department of Chemistry, Faculty of Science, Kyoto University, Japan.
authors.forename: R
authors.initials: R
authors.lastname: Ishima
authors.forename: A
authors.initials: A
authors.lastname: Tamura
authors.forename: K
authors.initials: K
authors.lastname: Akasaka
authors.forename: K
authors.initials: K
authors.lastname: Hamaguchi
authors.forename: K
authors.initials: K
authors.lastname: Makino
authors.forename: T
authors.initials: T
authors.lastname: Murachi
authors.forename: M
authors.initials: M
authors.lastname: Hatanaka
authors.forename: M
authors.initials: M
authors.lastname: Maki
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D002135:Calcium-Binding Proteins / Q000737:chemistry*; D015853:Cysteine Proteinase Inhibitors / Q000737:chemistry*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000737:chemistry; D011487:Protein Conformation
chemical_list: D002135:Calcium-Binding Proteins; D015853:Cysteine Proteinase Inhibitors; D010446:Peptide Fragments; C033668:calpastatin