Structural enzymology of cholesterol biosynthesis and storage.

Cholesterol biosynthesis occurs in the endoplasmic reticulum (ER). Its lego-like construction from water-soluble small metabolites via intermediates of increasing complexity to water-insoluble cholesterol requires numerous distinct enzymes. Dysfunction of the involved enzymes can cause several human inborn defects and diseases. Here, we review recent structures of three key cholesterol biosynthetic enzymes: Squalene epoxidase (SQLE), NAD(P)-dependent steroid dehydrogenase-like (NSDHL), and 3β-hydroxysteroid