1MZ9

Storage function of COMP:the crystal structure of the coiled-coil domain in complex with vitamin D3

Summary for 1MZ9

• Entry DOI: 10.2210/pdb1mz9/pdb
• Descriptor: cartilage oligomeric matrix protein, 3-{2-[1-(5-HYDROXY-1,5-DIMETHYL-HEXYL)-7A-METHYL-OCTAHYDRO-INDEN-4-YLIDENE]-ETHYLIDENE}-4-METHYLENE-CYCLOHEXANOL (3 entities in total)
• Functional Keywords: pentameric coiled-coil domain, protein binding
• Biological source: Mus musculus (house mouse)
• Cellular location: Secreted, extracellular space, extracellular matrix (By similarity): Q9R0G6
• Total number of polymer chains: 5
• Total formula weight: 27011.66

Authors

Stetefeld, J. (deposition date: 2002-10-07, release date: 2003-01-28, Last modification date: 2024-11-20)

Primary citation

Ozbek, S.,Engel, J.,Stetefeld, J.
Storage function of cartilage oligomeric matrix protein: the crystal structure of the coiled-coil domain in complex with vitamin D(3).
EMBO J., 21:5960-5968, 2002

PubMed Abstract: The five-stranded coiled-coil domain of cartilage oligomeric matrix protein (COMPcc) forms a continuous axial pore with binding capacities for hydrophobic compounds, including prominent cell signalling molecules. Here, we report the X-ray structure of the COMPcc domain in complex with vitamin D(3) at 1.7 A resolution. The COMPcc pentamer harbours two molecules of the steroid hormone precursor in a planar s-trans conformation of the conjugated triene, with the aliphatic tails lying along the molecule axis. A hydrophilic ring of five Gln54 side chains divides the channel into two hydrophobic compartments in which the bound vitamin D(3) pair is fixed in a head-to-head orientation. Vitamin D(3) binding induces a volumetric increase of the cavities of approximately 30% while the main chain distances of the pentamer are retained. This adaptation to the bulky ring systems of the ligands is accomplished by a rotamer re-orientation of beta-branched side chains that form the knobs into holes of the coiled-coil structure. Compared with binding of vitamin D and retinoic acid by their classical receptors, COMP exerts a distinct mechanism of interaction mainly defined by the pattern of hydrophobic core residues.

PubMed: 12426368
DOI: 10.1093/emboj/cdf628

Experimental method

X-RAY DIFFRACTION (1.7 Å)