1ldl
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THREE-DIMENSIONAL STRUCTURE OF A CYSTEINE-RICH REPEAT FROM THE LOW-DENSITY LIPOPROTEIN RECEPTOR
OverviewOverview
The low-density lipoprotein (LDL) receptor plays a central role in, mammalian cholesterol metabolism, clearing lipoproteins which bear, apolipoproteins E and B-100 from plasma. Mutations in this molecule are, associated with familial hypercholesterolemia, a condition which leads to, an elevated plasma cholesterol concentration and accelerated, atherosclerosis. The N-terminal segment of the LDL receptor contains a, heptad of cysteine-rich repeats that bind the lipoproteins. Similar, repeats are present in related receptors, including the very low-density, lipoprotein receptor and the LDL receptor-related protein/alpha, 2-macroglobulin receptor, and in proteins which are functionally, unrelated, such as the C9 component of complement. The first repeat of the, human LDL receptor has been expressed in Escherichia coli as a glutathione, S-transferase fusion protein, and the cleaved and purified receptor module, has been shown to fold to a single, fully oxidized form that is recognized, by the monoclonal antibody IgG-C7 in the presence of calcium ions. The, three-dimensional structure of this module has been determined by, two-dimensional NMR spectroscopy and shown to consist of a beta-hairpin, structure, followed by a series of beta turns. Many of the side chains of, the acidic residues, including the highly conserved Ser-Asp-Glu triad, are, clustered on one face of the module. To our knowledge, this structure has, not previously been described in any other protein and may represent a, structural paradigm both for the other modules in the LDL receptor and for, the homologous domains of several other proteins. Calcium ions had only, minor effects on the CD spectrum and no effect on the 1H NMR spectrum of, the repeat, suggesting that they induce no significant conformational, change.
DiseaseDisease
Known disease associated with this structure: Hypercholesterolemia, familial OMIM:[606945]
About this StructureAbout this Structure
1LDL is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
ReferenceReference
Three-dimensional structure of a cysteine-rich repeat from the low-density lipoprotein receptor., Daly NL, Scanlon MJ, Djordjevic JT, Kroon PA, Smith R, Proc Natl Acad Sci U S A. 1995 Jul 3;92(14):6334-8. PMID:7603991
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