Dataset Information

Selective steroidogenic cytochrome P450 haem iron ligation by steroid-derived isonitriles.

ABSTRACT: Alkyl isonitriles, R-NC, have previously been shown to ligate the heme (haem) iron of cytochromes P450 in both accessible oxidation states (ferrous, Fe²⁺, and ferric, Fe³⁺). Herein, the preparation of four steroid-derived isonitriles and their interactions with several P450s, including the steroidogenic CYP17A1 and CYP106A2, as well as the more promiscuous drug metabolizers CYP3A4 and CYP2D6, is described. It was found that successful ligation of the heme iron by the isonitrile functionality for a given P450 depends on both the position and stereochemistry of the isonitrile on the steroid skeleton. Spectral studies indicate that isonitrile ligation of the ferric heme is stable upon reduction to the ferrous form, with reoxidation resulting in the original complex. A crystallographic structure of CYP17A1 with an isonitrile derived from pregnanalone further confirmed the interaction and identified the absolute stereochemistry of the bound species.

SUBMITTER: Richard AM

PROVIDER: S-EPMC10475101 | biostudies-literature | 2023 Sep

REPOSITORIES: biostudies-literature

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Selective steroidogenic cytochrome P450 haem iron ligation by steroid-derived isonitriles.

Richard Alaina M AM Wong Nathan R NR Harris Kurt K Sundar Reethy R Scott Emily E EE Pochapsky Thomas C TC

Communications chemistry 20230902 1

Alkyl isonitriles, R-NC, have previously been shown to ligate the heme (haem) iron of cytochromes P450 in both accessible oxidation states (ferrous, Fe<sup>2+</sup>, and ferric, Fe<sup>3+</sup>). Herein, the preparation of four steroid-derived isonitriles and their interactions with several P450s, including the steroidogenic CYP17A1 and CYP106A2, as well as the more promiscuous drug metabolizers CYP3A4 and CYP2D6, is described. It was found that successful ligation of the heme iron by the isonit ...[more]

PMID: 37660137

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Project description:BackgroundCytochrome P450 monooxygenases--able to regio- and stereoselectively hydroxylate non-activated carbon atoms--are important enzymes for the synthesis of valuable intermediates in the production of steroid hormones in the pharmaceutical industry. However, up to now only a few bacterial enzymes able to hydroxylate steroids have been reported. CYP154C5 from Nocardia farcinica IFM 10152, a bacterial P450 monooxygenase, was previously shown to convert testosterone to 16α-hydroxytestosterone. Since the hydroxylation at 16α-position is of special interest for the pharmaceutical industry, we have studied this enzyme in more detail to investigate its activity and selectivity in bioconversions of further steroids.ResultsCYP154C5 was coexpressed in Escherichia coli together with putidaredoxin and putidaredoxin reductase from Pseudomonas putida as redox partners for electron transfer and applied in bioconversions of various pregnanes and androstanes [pregnenolone (1), dehydroepiandrosterone (2), progesterone (3), androstenedione (4), testosterone (5) and nandrolone (6)]. Structure elucidation of the formed products revealed an exclusive regio- and stereoselectivity of CYP154C5, always yielding the corresponding 16α-hydroxylated steroids. Application of whole cells expressing the three components, P450, Pdx and PdR, in steroid biotransformations resulted in significantly higher conversions and total turnover numbers (TTN) compared to reactions using cell-free extracts. Additionally, considerably higher substrate loads (up to 15 mM) were tolerated by the whole-cell system. Furthermore, turnover numbers (TON) were determined for the six different steroids using whole cells. Thus, testosterone was found to be the worst substrate with a TON of only 0.8 μmol substrate consumed min-1 μmol(-1) CYP154C5, while progesterone and pregnenolone were converted the fastest resulting in TON of 3.3 μmol substrate consumed min(-1) μmol(-1) CYP154C5.ConclusionCYP154C5 from N. farcinica constitutes a promising catalyst due to its high regio- and stereoselectivity in the hydroxylation of different steroids as well as its efficient expression in E. coli at high yields. Using this enzyme, 16α-hydroxylated steroids, which are important precursors for the synthesis of high value steroidal drugs in the pharmaceutical industry, can be selectively produced on preparative scale with TTN (μmol substrate consumed μmol(-1) CYP154C5) exceeding 2000.

Dataset Information

Selective steroidogenic cytochrome P450 haem iron ligation by steroid-derived isonitriles.

Publications

Selective steroidogenic cytochrome P450 haem iron ligation by steroid-derived isonitriles.

Similar Datasets

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