Modification Strategy of Two-Step Ordered Selective Hydroxylation of DHEA Catalyzed by CYP-cl3

Area of Science:

• Biocatalysis
• Enzyme Engineering
• Medicinal Chemistry

Background:

• Cytochrome P450 (P450) enzymes are crucial for steroid drug synthesis via hydroxylation.
• Existing P450 dihydroxylases exhibit poor catalytic performance and imbalanced two-step hydroxylation, hindering efficient synthesis of dihydroxylated steroids.

Purpose of the Study:

• To elucidate the hydroxylation sequence of DHEA (dehydroepiandrosterone) to 7α,15α-diOH-DHEA catalyzed by CYP-cl3.
• To engineer a highly selective and efficient P450 dihydroxylase for steroid synthesis.

Main Methods:

• Computational analysis to determine the hydroxylation sequence (C7 then C15).
• A three-step enzyme modification strategy: high-throughput screening, semi-rational design, and mutation site combination.
• Molecular docking and dynamics simulations to understand the mechanism of improved catalytic performance.

Main Results:

• The hydroxylation sequence of DHEA by CYP-cl3 was determined as C7α followed by C15α.
• A quadruple mutant (A83P/E264I/V281A/T315P) was successfully engineered.
• The engineered mutant achieved a 99.9% proportion of the desired 7α,15α-diOH-DHEA product.

Conclusions:

• The study successfully enhanced the catalytic performance and selectivity of P450 dihydroxylase for steroid synthesis.
• The engineered enzyme provides an efficient route to key steroid drug precursors.
• The findings offer guidance for improving other P450 hydroxylases.