Secondary structure of the α-amylase polypeptide inhibitor Tendamistat from Streptomyces tendae determined in solution by 1H nuclear magnetic resonance

Abstract

Complete sequence-specific 1H nuclear magnetic resonance assignments were obtained for the backbone hydrogen atoms in Tendamistat, a protein with 74 residues. From NOESY observation of 1H- 1H short distance constraints, measurements of the spin-spin couplings 3J HNα and a qualitative identification of slowly exchanging amide protons, two antiparallel β-sheets containing three and four strands, respectively, were identified. The peptide segments outside the β-sheets do not form regular secondary structure. Preliminary data were obtained on the relative spatial arrangements of the two β-sheets.