Related Experiment Videos
Modelling the catalytic reaction in human aldose reductase.
P Várnai1, W G Richards, P D Lyne
1Physical and Theoretical Chemistry Laboratory, Oxford University, United Kingdom.
Proteins
|December 3, 1999
Summary
Aldose reductase (ALR2) simulations reveal key catalytic steps in diabetic complications. Protonated Histidine 110 is the favored proton donor over Tyrosine 48 for D-glyceraldehyde reduction.
Area of Science:
- Biochemistry
- Computational Chemistry
- Enzymology
Background:
- Aldose reductase (ALR2) is implicated in diabetic complications.
- Its catalytic mechanism, particularly hydride and proton transfer, remains incompletely understood despite structural and kinetic data.
Purpose of the Study:
- To elucidate the hydride and proton transfer steps in D-glyceraldehyde reduction by ALR2 using QM-MM simulations.
- To investigate the roles of Tyr48 and protonated His110+ as potential proton donors.
Main Methods:
- Hybrid quantum mechanical/molecular mechanical (QM-MM) potential for computer simulations.
- Investigation of multiple reaction pathways in two distinct active site models.
- Analysis of substrate binding and stereospecific catalysis.
Main Results:
- Substrate binding via hydrogen bonds facilitates stereospecific catalysis in both models.
- Protonated His110+ is the energetically favored proton donor compared to Tyr48 when His110 is neutral.
- Distinct reaction mechanisms were identified based on structural and energetic factors.
Conclusions:
- The study provides detailed insights into the catalytic mechanism of aldose reductase.
- Protonated Histidine 110 plays a crucial role as the preferred proton donor in the ALR2 active site.
- Computational simulations are valuable for understanding enzyme reaction pathways and their link to disease.