Molecular mechanism for inhibition of 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) reductase by rosuvastatin

Abstract

The statins are inhibitors of 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) reductase (HMG-CoAR), and are utilized to decrease levels of atherogenic lipoproteins in patients with, or who are at high risk of, cardiovascular disease. This study describes the inhibition of a recombinant, catalytic fragment of human HMG-CoAR by a new statin, rosuvastatin (CRESTOR(R)). Binding is reversible and involves an initial complex [inhibition constant involving the enzyme-inhibitor complex (E.I), K (i), approximately 1 nM], which undergoes a slow transition ( t ((1/2)) to reach steady state is 33-360 s) to give tighter association [steady-state inhibition constant involving E.I and the second E.I complex in a two-step mechanism (E.I*), K (i)*, approximately 0.1 nM]. At steady state, rosuvastatin is at least as potent as atorvastatin, cerivastatin and simvastatin. It is more potent than fluvastatin and pravastatin. For rosuvastatin, inhibition kinetics are competitive with respect to HMG-CoA and non-competitive when NADPH is varied. At 37 degrees C, binding is linked to a large favourable enthalpy change [Delta H degrees =-69.0 kJ/mol (-16.5 kcal/mol)] and a small entropic penalty [ T Delta S degrees =-9.6 kJ/mol (-2.3 kcal/mol)]. These characteristics, and the high affinity relative to that of 3 S -HMG-CoA ( K (d) approximately 6.6 microM), are discussed in relation to the crystal structures of complexes with HMG-CoAR.

Implication of HMGR in homeostasis of sequestered and de novo produced precursors of the iridoid biosynthesis in leaf beetle larvae

“…Insect HMGR was inhibited by fluvastatin with an IC 50 of about 220 nM. In human an IC 50 ¼ 28 nM has been reported (Holdgate et al, 2003). Clear inhibition of activity of the catalytic domain was shown for 8-hydroxygeraniol.…”

The statin class of HMG-CoA reductase inhibitors demonstrate differential activation of the nuclear receptors PXR, CAR and FXR, as well as their downstream target genes

“…Whereas the majority of statins posses a high degree of lipophillicity (logD7.0>1.5), both pravastatin (logD7.0=0.5) and rosuvastatin (logD7.5=0.5) are relatively hydrophilic, resulting in the requirement for SLCO-mediated uptake into hepatocytes (Hirano et al 2005;Holdgate et al 2003;Ishigami et al 2001): It is hence possible that the lack of activation of the CYP3A4 reporter gene by rosuvastatin and pravastatin may be due to lack of compound access. To examine this possibility, we modulated expression of SLCO1B1 (Figure 4), the main uptake transporter for pravastatin and rosuvastatin in hepatocytes (Ho et al 2006;Nakai et al 2001), and re-examined the impact of these statins on CYP3A4 reporter gene expression.…”

Affinity-based, biophysical methods to detect and analyze ligand binding to recombinant proteins: Matching high information content with high throughput

“…The approach is theoretically simple: rather than establishing SAR on the binding affinity alone to improve the affinity of test compounds, more efficient optimization can be achieved if the contributions of enthalpy and entropy are considered and improved simultaneously (Freire, 2009). The thermodynamics of the AstraZeneca statin, Crestor, were evaluated in the context of both the structure and kinetics of the complex with the target protein, HMG-CoA Reductase (Holdgate et al, 2003). However, it should be remembered that although improving enthalpy is a useful strategy for medicinal chemists, sometimes interpreting changes, even relatively small changes in structure can be difficult.…”