8eg3
Structure of human placental steroid (estrone/DHEA) sulfatase at 2.0 angstrom resolution
Structural highlights
DiseaseSTS_HUMAN Defects in STS are the cause of ichthyosis X-linked (IXL) [MIM:308100. Ichthyosis X-linked is a keratinization disorder manifesting with mild erythroderma and generalized exfoliation of the skin within a few weeks after birth. Affected boys later develop large, polygonal, dark brown scales, especially on the neck, extremities, trunk, and buttocks.[1] [2] [3] [4] FunctionSTS_HUMAN Conversion of sulfated steroid precursors to estrogens during pregnancy. Publication Abstract from PubMedHuman placental estrone (E1)/dehydroepiandrosterone (DHEA) sulfatase (human placental steroid sulfatase; hSTS) is an integral membrane protein of the endoplasmic reticulum. This Ca(2+)-dependent enzyme catalyzes the hydrolysis of sulfate esters of E1 and DHEA to yield the respective unconjugated steroids, which then act as precursors for the biosynthesis of 17beta-estradiol (E2) and dihydrotestosterone (DHT), respectively, the most potent forms of estrogens and androgens. hSTS is a key enzyme for the local production of E2 and DHT in the breast and the prostate. The enzyme is known to be responsible for maintaining high levels of estrogens in the breast tumor cells. The crystal structure of hSTS purified from human placenta has previously been reported at 2.6 A resolution. Here we present the structure of hSTS determined at the superior 2.0 A resolution bringing new clarity to the atomic architecture of the active site. The molecular basis of catalysis and steroid-protein interaction are revisited in light of the new data. We also reexamine the enzyme's quaternary association and its implication on the membrane integration. A secondary ligand binding pocket at the intermolecular interface and adjacent to the active site access channel, buried into the gill of the mushroom-shaped molecule, has been identified. Its role as well as that of a phosphate ion bound to an exposed histidine side chain are examined from the structure-function perspective. Higher resolution data also aids in the tracing of an important loop missing in the previous structure. Structure of human placental steroid sulfatase at 2.0 angstrom resolution: Catalysis, quaternary association, and a secondary ligand site.,Ghosh D J Steroid Biochem Mol Biol. 2022 Nov 24;227:106228. doi: , 10.1016/j.jsbmb.2022.106228. PMID:36427797[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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