Tris(hydroxymethyl)aminomethane induces conformational change and crystal-packing contraction of porcine pancreatic elastase.

ABSTRACT: Porcine pancreatic elastase (PPE) was crystallized under new sulfate-free conditions containing 0.3 M NaCl and 50 mM tris(hydroxymethyl)aminomethane-HCl at pH 7.0. The crystal structure determined at 1.5 angstroms 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 chang

SUBMITTER: Kinoshita T 

PROVIDER: S-EPMC2242949 | biostudies-literature | 2006 Jul

REPOSITORIES: biostudies-literature