1mz9
From Proteopedia
Storage function of COMP:the crystal structure of the coiled-coil domain in complex with vitamin D3
Overview
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.
About this Structure
1MZ9 is a Single protein structure of sequence from Mus musculus. Full crystallographic information is available from OCA.
Reference
Storage function of cartilage oligomeric matrix protein: the crystal structure of the coiled-coil domain in complex with vitamin D(3)., Ozbek S, Engel J, Stetefeld J, EMBO J. 2002 Nov 15;21(22):5960-8. PMID:12426368 Page seeded by OCA on Sat May 3 01:53:22 2008
