th  - 1987 - 51st ENC Conference

MKI1
THE STRUCTURE OF THE SUBTILISIN INHIBITOR 2 FROM BARLEY DETERMINED
BY IH-NMR SPECTROSCOPY, DISTANCE GEOMETRY CALCULATIONS AND
RESTRAINED MOLECULAR DYNAMICS.
e
Flemming M. Poulsen i) Mogens KJ~r l) and Marius Clore 2)
i) Department of Chemistry, Carlsberg Laboratory, Gamle Carlsberg Vej 10,
DK-2500 Copenhagen Valby, Denmark
2} Max-Planck-Institut f~r Biochemie, D-8033 Martinsried bei M~nchen,
Federal Republic of Germany
The barley subtilisin inhibitor is a protein of 83 residues, homologous
to leech eglin c. The structure of the C-terminal part of the protein
consisting of 65 residues has been studied using 2D-NMR techniques. The
secondary structure has been determined, and consists of three short
stretches of antiparrallel ~-sheet one long stretch of parallel ~-sheet
furthermore one helix of 12-13 residues and a long loop.
On the basis of approximately 300 assigned NOE's the structure has
been calculated using distance geometry calculations. Subsequently
restrained molecular dynamics was used to refine the structure.
The structure obtained from NMR data agree's well with the structure
of the inhibitor determined by X-ray crystallography of the subtilisin-
inhibitor complex.