ABSTRACT
d-Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) shows cooperative properties for binding coenzymes. The structure of apo-GAPDH from Palinurus versicolor has been solved at 2.0 A resolution by X-ray crystallography. The final model gives a crystallographic R factor of 0.178 in the resolution range 8 to 2 A. The structural comparison with holo-GAPDH from the same species reveals a conformational change induced by coenzyme binding similar to that observed in Bacillus stearothermophilus GAPDH but to a lesser extent. The differences in magnitude during the apo-holo transition between these two enzymes were analyzed with respect to the change of the amino acid composition in the coenzyme binding pocket. In the crystalline state of apo-GAPDH, the overall structures of the subunits are similar to each other; however, significant differences in temperature factors and minor differences in domain rotation upon coenzyme binding were observed for different subunits. These structural features are discussed in relation to the environmental asymmetry of crystallographically independent subunits.
Subject(s)
Glyceraldehyde-3-Phosphate Dehydrogenases/chemistry , Nephropidae/enzymology , Animals , Apoenzymes/chemistry , Crystallography, X-Ray , Holoenzymes/chemistry , Models, Molecular , Protein Conformation , Protein Structure, Quaternary , Static ElectricityABSTRACT
This study deals with the antiulcer effect of water extract and ether extract of Cinnamomum cassia on four types of experimental gastric ulcer and with the antidiarrhea effect on two types of medicine-induced diarrhea in mice. These extracts have choleretic effect in anesthetized rats, and are analgesic as well. This is the pharmacologic basis of spleen-stomach warming and analgesic action of Cinnamomum cassia.