TY - JOUR
T1 - Binding thermodynamics of statins to HMG-CoA reductase
AU - Carbonell, Teresa
AU - Freire, Ernesto
PY - 2005/9/6
Y1 - 2005/9/6
N2 - The statins are powerful inhibitors of 3-hydroxy-3-methyl glutaryl coenzyme A reductase (HMG-CoA reductase), the key enzyme in the cholesterol biosynthetic pathway, and are among the most widely prescribed drugs in the world. Despite their clinical importance, little is known about the binding thermodynamics of statins to HMG-CoA reductase. In this paper, we report the results of inhibition kinetics and microcalorimetric analysis of a representative type I statin (pravastatin) and four type II statins (fluvastatin, cerivastatin, atorvastatin, and rosuvastatin). Inhibition constants (Ki) range from 2 to 250 nM for the different statins. Isothermal titration calorimetry (ITC) experiments yield binding enthalpies (ΔHbinding) ranging between zero and -9.3 kcal/mol at 25 °C. There is a clear correlation between binding affinity and binding enthalpy: the most powerful statins bind with the strongest enthalpies. The proportion by which the binding enthalpy contributes to the binding affinity is not the same for all statins, indicating that the balance among hydrogen bonding, van der Waals, and hydrophobic interactions is not the same for all of them. At 25 °C, the dominant contribution to the binding affinity of fluvastatin, pravastatin, cerivastatin, and atorvastatin is the entropy change. Only for rosuvastatin does the enthalpy change contribute more than 50% of the total binding energy (76%). Since the enthalpic and entropic contributions to binding originate from different types of interactions, the thermodynamic dissection presented here provides a way to identify interactions that are critical for affinity and specificity.
AB - The statins are powerful inhibitors of 3-hydroxy-3-methyl glutaryl coenzyme A reductase (HMG-CoA reductase), the key enzyme in the cholesterol biosynthetic pathway, and are among the most widely prescribed drugs in the world. Despite their clinical importance, little is known about the binding thermodynamics of statins to HMG-CoA reductase. In this paper, we report the results of inhibition kinetics and microcalorimetric analysis of a representative type I statin (pravastatin) and four type II statins (fluvastatin, cerivastatin, atorvastatin, and rosuvastatin). Inhibition constants (Ki) range from 2 to 250 nM for the different statins. Isothermal titration calorimetry (ITC) experiments yield binding enthalpies (ΔHbinding) ranging between zero and -9.3 kcal/mol at 25 °C. There is a clear correlation between binding affinity and binding enthalpy: the most powerful statins bind with the strongest enthalpies. The proportion by which the binding enthalpy contributes to the binding affinity is not the same for all statins, indicating that the balance among hydrogen bonding, van der Waals, and hydrophobic interactions is not the same for all of them. At 25 °C, the dominant contribution to the binding affinity of fluvastatin, pravastatin, cerivastatin, and atorvastatin is the entropy change. Only for rosuvastatin does the enthalpy change contribute more than 50% of the total binding energy (76%). Since the enthalpic and entropic contributions to binding originate from different types of interactions, the thermodynamic dissection presented here provides a way to identify interactions that are critical for affinity and specificity.
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U2 - 10.1021/bi050905v
DO - 10.1021/bi050905v
M3 - Article
C2 - 16128575
AN - SCOPUS:24344452953
SN - 0006-2960
VL - 44
SP - 11741
EP - 11748
JO - Biochemistry
JF - Biochemistry
IS - 35
ER -