1hcn

STRUCTURE OF HUMAN CHORIONIC GONADOTROPIN AT 2.6 ANGSTROMS RESOLUTION FROM MAD ANALYSIS OF THE SELENOMETHIONYL PROTEIN

spinqualitylabelsall models 1hcn, resolution 2.60Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1hcn is a 2 chain structure. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: NAG Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed BACKGROUND: Human chorionic gonadotropin (hCG) is a placental hormone that stimulates secretion of the pregnancy-sustaining steroid progesterone. It is a member of a family of glycoprotein hormones that are disulfide-rich heterodimers, with a common alpha-chain and distinctive beta-chains specific to their particular G-protein linked receptors. RESULTS: We have produced recombinant hCG in mammalian cells as the selenomethionyl protein, and have determined its structure (after partial deglycosylation) at 2.6 A resolution from multiwavelength anomalous diffraction (MAD) measurements. Despite only limited sequence similarity (10% identity), the alpha- and beta-subunits of hCG have similar tertiary folds. Each subunit has a cystine-knot motif at its core of extended hairpin loops. There is a very extensive subunit interface featuring two inter-chain beta-sheets and a unique, disulfide-tethered 'arm' from the beta-subunit which 'embraces' the alpha-subunit. The carboxy-terminal peptide of the beta-subunit, which is rich in O-linked sugars, is disordered. CONCLUSIONS: Structural and sequence comparisons indicate an evolutionary homology, albeit remote, between the glycoprotein hormone chains and other cystine-knot proteins, notably platelet-derived growth factor. Segments of the alpha- and beta-chains that have been convincingly implicated in receptor binding by hCG are juxtaposed on one side of the molecule. A glycosylation site implicated in signal transduction but not in binding is also close to the presumed binding site suggesting a possible coupling between ligand binding and signaling. This study with selenomethionyl protein produced in mammalian cells extends the realm of MAD phasing. Structure of human chorionic gonadotropin at 2.6 A resolution from MAD analysis of the selenomethionyl protein.,Wu H, Lustbader JW, Liu Y, Canfield RE, Hendrickson WA Structure. 1994 Jun 15;2(6):545-58. PMID:7922031 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Hormone Human Follicle-Stimulating Hormone Complexed with its Receptor

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