Structure of the active 27-residue fragment of human calpastatin.
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.
Ishima
R
R
Department of Chemistry, Faculty of Science, Kyoto University, Japan.
Tamura
A
A
Akasaka
K
K
Hamaguchi
K
K
Makino
K
K
Murachi
T
T
Hatanaka
M
M
Maki
M
M
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
D002135:Calcium-Binding Proteins; D015853:Cysteine Proteinase Inhibitors; D010446:Peptide Fragments; C033668:calpastatin