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PH8755: is a 9-residue peptide antibiotic
having a pure alpha-helical conformation
contains 5 residues of the unusual amino acid
alpha-aminoisobutyric acid
ToxII: Scorpion Protein Toxin
64 residue scorpion toxin
0.96A data
only information known: approx 500 atoms & 4 disulfide bonds
starting model: 5 fragments varying in length from 5 to 18 residues for a total of 241 atoms
structure revealed following Xplor refinement and Fourier maps
60/64 residues identified correctly
final R factor of 0.160 for
512 protein atoms,
112 water molecules and
418 protein hydrogen atoms
Phase error of 19 deg. between SnB phases and final