title: The C(19) position of 25-hydroxyvitamin D(3) faces outward in the vitamin D sterol-binding pocket of vitamin D-binding protein.
abstract: The radiolabeled affinity and photoaffinity analogues of 25-hydroxyvitamin D(3) (25-OH-D(3)) with probes at the C-19 position failed to specifically label the 25-OH-D(3)-binding pocket of vitamin D-binding protein (DBP). However, a hybrid analogue, with a bromoacetate affinity probe and a photoaffinity probe at C(3)-OH and C(19) positions, respectively, specifically labeled the ligand-binding pocket, suggesting that C(3)-OH points towards the 'inside' of the binding cavity while the C(19) position faces away from it.
authors.affiliation: Bioorganic Chemistry & Structural Biology, Section in Endocrinology, Diabetes and Metabolism, Department of Medicine, Boston University School of Medicine, Boston, MA 02118, USA.
authors.forename: James K
authors.initials: JK
authors.lastname: Addo
authors.forename: Narasimha
authors.initials: N
authors.lastname: Swamy
authors.forename: Rahul
authors.initials: R
authors.lastname: Ray
mesh_terms: D001665:Binding Sites; D001667:Binding, Competitive / Q000187:drug effects; D002112:Calcifediol / Q000737:chemistry*; D008024:Ligands; D019920:Photoaffinity Labels; D013261:Sterols / Q000737:chemistry*; D013329:Structure-Activity Relationship; D014807:Vitamin D / Q000737:chemistry*; D014809:Vitamin D-Binding Protein / Q000737:chemistry*
chemical_list: D008024:Ligands; D019920:Photoaffinity Labels; D013261:Sterols; D014809:Vitamin D-Binding Protein; D014807:Vitamin D; D002112:Calcifediol