The Multienzyme Complex Nature of Dehydroepiandrosterone Sulfate Biosynthesis

Area of Science:

• Biochemistry
• Molecular Biology
• Endocrinology

Background:

• Dehydroepiandrosterone (DHEA) is a key steroid sex hormone precursor.
• DHEA synthesis involves CYP17A1, CYB5A, CPR, and subsequent sulfation by SULT1E1 and SULT2A1.
• The interactions between these enzymes were not well understood.

Purpose of the Study:

• To investigate the interactions between sulfotransferases (SULTs) and the dehydroepiandrosterone (DHEA)-producing enzyme CYP17A1 and its redox partners.
• To elucidate the organization of microsomal CYP-dependent macromolecular complexes.

Main Methods:

• Text mining analysis
• Protein-protein network analysis
• Gene co-expression analysis
• Surface plasmon resonance (SPR)
• Affinity purification coupled with mass spectrometry (AP-MS)
• Enzymatic activity assays
• Computational structure prediction

Main Results:

• SPR confirmed direct interactions between CYP17A1 and SULT2A1 or SULT1E1.
• SULTs were found to interact with CYB5A and CPR.
• 3'-phosphoadenosine-5'-phosphosulfate (PAPS) modulated SULT2A1/CYP17A1 and SULT2A1/CYB5A complex parameters.
• AP-MS identified CYB5A as a SULT1E1 partner.
• SULT enzymatic activity increased in the presence of CYP17A1 and CYB5A.
• Complex structures of CYP17A1/SULT1E1 and CYB5A/SULT1E1 were predicted.

Conclusions:

• This study provides the first direct evidence of interactions between SULTs and CYP17A1, CYB5A, and CPR.
• These interactions are crucial for the organization of microsomal CYP-dependent macromolecular complexes.
• The findings offer fundamental insights into steroid hormone synthesis regulation.