scholarly journals Pyranoflavones: A Group of Small-Molecule Probes for Exploring the Active Site Cavities of Cytochrome P450 Enzymes 1A1, 1A2, and 1B1

2013 ◽  
Vol 56 (10) ◽  
pp. 4082-4092 ◽  
Author(s):  
Jiawang Liu ◽  
Shannon F. Taylor ◽  
Patrick S. Dupart ◽  
Corey L. Arnold ◽  
Jayalakshmi Sridhar ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Small Molecule ◽  
Active Site ◽  
Cytochrome P450 Enzymes ◽  
Small Molecule Probes

scholarly journals Structure of an ancestral mammalian family 1B1 cytochrome P450 with increased thermostability

2020 ◽  
Vol 295 (17) ◽  
pp. 5640-5653 ◽  
Author(s):  
Aaron G. Bart ◽  
Kurt L. Harris ◽  
Elizabeth M. J. Gillam ◽  
Emily E. Scott
Keyword(s):  
Cytochrome P450 ◽  
Active Site ◽  
Substrate Selectivity ◽  
Cytochrome P450 Enzymes ◽  
Drug Molecules ◽  
Structural Evaluation ◽  
Aromatic Interactions ◽  
Open Conformation ◽  
17Β Estradiol ◽  
Variable Substrate

Mammalian cytochrome P450 enzymes often metabolize many pharmaceuticals and other xenobiotics, a feature that is valuable in a biotechnology setting. However, extant P450 enzymes are typically relatively unstable, with T50 values of ∼30–40 °C. Reconstructed ancestral cytochrome P450 enzymes tend to have variable substrate selectivity compared with related extant forms, but they also have higher thermostability and therefore may be excellent tools for commercial biosynthesis of important intermediates, final drug molecules, or drug metabolites. The mammalian ancestor of the cytochrome P450 1B subfamily was herein characterized structurally and functionally, revealing differences from the extant human CYP1B1 in ligand binding, metabolism, and potential molecular contributors to its thermostability. Whereas extant human CYP1B1 has one molecule of α-naphthoflavone in a closed active site, we observed that subtle amino acid substitutions outside the active site in the ancestor CYP1B enzyme yielded an open active site with four ligand copies. A structure of the ancestor with 17β-estradiol revealed only one molecule in the active site, which still had the same open conformation. Detailed comparisons between the extant and ancestor forms revealed increases in electrostatic and aromatic interactions between distinct secondary structure elements in the ancestral forms that may contribute to their thermostability. To the best of our knowledge, this represents the first structural evaluation of a reconstructed ancestral cytochrome P450, revealing key features that appear to contribute to its thermostability.

scholarly journals The quasi-irreversible inactivation of cytochrome P450 enzymes by paroxetine: a computational approach

2020 ◽  
Vol 18 (17) ◽  
pp. 3334-3345
Author(s):  
Emadeldin M. Kamel ◽  
Al Mokhtar Lamsabhi
Keyword(s):  
Cytochrome P450 ◽  
Active Site ◽  
Active Sites ◽  
Heme Iron ◽  
Computational Approach ◽  
Cytochrome P450 Enzymes

The potency of paroxetine as a P450 inhibitor is mainly attributed to the availability of two active sites on its structure, its compatibility with P450's active site and the ease of its tight coordination to heme iron.

Abstract MP11: Aldosterone Synthase Structure With Cushing’s Disease Drug Osilodrostat Provides Clues For Treatment Of Primary Aldosteronism

Hypertension ◽  
2020 ◽  
Vol 76 (Suppl_1) ◽  
Author(s):  
Simone Brixius-Anderko ◽  
Emily E Scott
Keyword(s):  
Cytochrome P450 ◽  
Cushing’S Disease ◽  
Active Site ◽  
Primary Aldosteronism ◽  
Therapeutic Option ◽  
Heme Iron ◽  
Cushing's Disease ◽  
Cytochrome P450 Enzymes ◽  
Aldosterone Synthase ◽  
Vis Spectroscopy

Primary aldosteronism, the major form of secondary hypertension, often leads to cardiac disease. It develops due to excess steroid hormone aldosterone produced by aldosterone synthase, also known as cytochrome P450 11B2. CYP11B2 is 93% identical to cortisol-producing CYP11B1, which makes it difficult to design drugs specifically targeting CYP11B2. Osilodrostat (LCI699, Isturisa®) was initially developed as CYP11B2 inhibitor, but due to higher potency for CYP11B1 is now the first FDA-approved drug for CYP11B1-mediated Cushing’s disease. Thus, there is still no effective therapeutic option targeting CYP11B2 for primary aldosteronism. To determine aspects of the CYP11B2/osilodrostat interaction that could be improved to design a more selective CYP11B2 inhibitor, this project took a structure/function approach. First, osilodrostat affinity to CYP11B2 was examined using UV/vis spectroscopy. Osilodrostat induced a spectral change typical of ligand nitrogen coordination to the catalytic heme iron, establishing the binding location and mode, and revealed high CYP11B2 affinity. X-ray crystallography was used to solve the structure of CYP11B2 bound to osilodrostat. Consistent with the spectral analysis, osilodrostat binds in the active site with its imidazole nitrogen coordinating the heme iron. Additional interactions occur with the osilodrostat fluorinated benzonitrile. Osilodrostat binding was compared with that of its analog fadrozole to both CYP11B enzymes. CYP11B2 binding of osilodrostat is similar to (R) -fadrozole, but the fluorination of osilodrostat mediates additional active site interactions. Comparison with the previously-available CYP11B1 structure reveals CYP11B1 favors (S) -fadrozole due to distinct CYP11B active site architectures. These results suggest an opportunity to optimize inhibitor sterics to better discriminate between these two steroidogenic cytochrome P450 enzymes. Exploiting structural differences between the CYP11B enzymes should promote the design of therapeutics for the treatment of primary aldosteronism targeting CYP11B2, while reducing undesirable side effects due to off-target CYP11B1 inhibition.

Exploring the active site of human factor Xa protein by NMR screening of small molecule probes

2003 ◽  
Vol 1 (23) ◽  
pp. 4235 ◽  
Author(s):  
Lee Fielding ◽  
Dan Fletcher ◽  
Samantha Rutherford ◽  
Jasmit Kaur ◽  
Jordi Mestres
Keyword(s):  
Small Molecule ◽  
Active Site ◽  
Human Factor ◽  
Factor Xa ◽  
Nmr Screening ◽  
Small Molecule Probes
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