Title : Structure of human
estrone sulfatase suggests functional roles of membrane association
Abstract :
- Estrone sulfatase ( ES ; 562 amino acids), one of the key enzymes responsible for maintaining high levels of estrogens in breast tumor cells, is associated with the membrane of the endoplasmic reticulum (ER)
- The structure of ES , purified from the microsomal fraction of human placentas, has been determined at 2.60-A resolution by x-ray crystallography
- This structure shows a domain consisting of two antiparallel alpha-helices that protrude from the roughly spherical molecule, thereby giving the molecule a "mushroom-like" shape
- These highly hydrophobic helices, each about 40 A long, are capable of traversing the membrane, thus presumably anchoring the functional domain on the membrane surface facing the ER lumen
- The location of the transmembrane domain is such that the opening to the active site , buried deep in a cavity of the "gill" of the "mushroom," rests near the membrane surface, thereby suggesting a role of the lipid bilayer in catalysis
- This simple architecture could be a prototype utilized by the ER membrane in dictating the form and the function of ER-resident enzymes
Output (sent_index, trigger,
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Output(Part-Of) (sent_index,
protein,
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*Output_Site_Fusion* (sent_index,
protein,
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site):