Related Experiment Video
Updated: Aug 8, 2026

X-Ray Crystallography to Study the Oligomeric State Transition of the Thermotoga maritima M42 Aminopeptidase TmPep1050
Published on: May 13, 2020
Crystallographic analysis of the complex between triosephosphate isomerase and 2-phosphoglycolate at 2.5-A
1Department of Chemistry, Massachusetts Institute of Technology, Cambridge 02139.
Abstract:
The binding of the transition-state analogue 2-phosphoglycolate to triosephosphate isomerase from yeast has been investigated crystallographically. An atomic model of the enzyme-inhibitor complex has been refined against data to 2.5-A resolution to a final R factor of 0.18. The interactions between the inhibitor and enzyme have been analyzed. The inhibitor forms hydrogen bonds to the side chains of His 95 and Glu 165. The latter hydrogen bond confirms that Glu 165 is protonated upon PGA binding. The structure of the complexed enzyme has been compared to that of the unbound form of the enzyme, and conformational changes have been observed: the side chain of Glu 165 moves over 2 A and a 10-residue flexible loop moves over 7 A to close over the active site. Spectroscopic results of phosphoglycolic acid binding to triosephosphate isomerase that have been amassed over the years are also explained in structural terms. The implications for catalysis are noted.
Related Concept Videos
Energy-requiring Steps of Glycolysis
Glycolysis: Preparatory Phase
Catalytically Perfect Enzymes
Introduction to Mechanisms of Enzyme Catalysis

