MONOHYDROGEN PHOSPHATE BINDING TO TRYPANOSOMAL TRIOSEPHOSPHATE ISOMERASE
Publication Abstract from PubMed
The three-dimensional structure of triosephosphate isomerase complexed with the competitive inhibitor SO-4(2) was determined by X-ray crystallography to a resolution of 0.24 nm. A comparison with the native crystal structure, where SO-4(2) is bound, revealed five changes: (a) a 0.10-nm shift of the anion-binding site; (b) a further closing of the flexible loop of the enzyme; (c) a 'swinging in' of the side chain of the catalytic Glu, that is chi 1 changes from (+) to (-) synclinal; (d) an altered water structure; (e) a disappearance of the conformational heterogeneity at the C-terminus of strand beta 7. Some of these changes may be related to the different hydrogen-bond pattern about the two different anions. However, the distance of 0.10 nm between the sulphur and phosphorus positions is unexpected and remains intriguing.
Anion binding at the active site of trypanosomal triosephosphate isomerase. Monohydrogen phosphate does not mimic sulphate.,Verlinde CL, Noble ME, Kalk KH, Groendijk H, Wierenga RK, Hol WG Eur J Biochem. 1991 May 23;198(1):53-7. PMID:2040290
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