Open AccessTris(hydroxymethyl)aminomethane induces conformational change and crystal‐packing contraction of porcine pancreatic elastase
Author(s) -
Yamaguchi Asako,
Tada Toshiji,
Kinoshita Takayoshi
Publication year - 2006
Publication title -
acta crystallographica section f
Language(s) - English
Resource type - Journals
ISSN - 1744-3091
DOI - 10.1107/s1744309106023001
Subject(s) - hydroxymethyl , tris , crystallography , chemistry , crystal structure , pancreatic elastase , catalytic triad , molecule , crystal (programming language) , chloride , conformational change , stereochemistry , catalysis , elastase , active site , organic chemistry , biochemistry , enzyme , computer science , programming language
Porcine pancreatic elastase (PPE) was crystallized under new sulfate‐free conditions containing 0.3 M NaCl and 50 m M tris(hydroxymethyl)aminomethane–HCl at pH 7.0. The crystal structure determined at 1.5 Å resolution had a unique conformation in four regions which contained loop portions. A chloride ion was bound near the catalytic triad instead of the sulfate ion in PDB entry 1qnj , a typical PPE crystal structure. However, the chloride ion did not affect the configuration of the catalytic triad. A tris(hydroxymethyl)aminomethane (Tris) molecule was bound to the S4 and S5 subsites in place of the adjacent molecule in the 1qnj crystal and played a significant role in the structural change of the region. The distortion in this region may subsequently have induced conformational changes in the other three regions. The fact that Tris and these four regions make a diagonal line in the ac plane may have affected the crystal‐packing contraction along the a and c axes in the crystal compared with the typical crystal.