1lj7
|
Crystal structure of calcium-depleted human C-reactive protein from perfectly twinned data
OverviewOverview
C-reactive protein is a member of the pentraxin family of oligomeric serum, proteins which has been conserved through evolution, homologues having, been found in every species in which they have been sought. Human, C-reactive protein (hCRP) is the classical acute-phase reactant produced, in large amounts in response to tissue damage and inflammation and is used, almost universally as a clinical indicator of infection and inflammation., The role of hCRP in host defence and the calcium-dependent ligand-binding, specificity of hCRP for phosphocholine moieties have long been recognized., In order to clarify the structural rearrangements associated with calcium, binding, the reported affinity of calcium-depleted hCRP for polycations, and other ligands, and the role of calcium in protection against, denaturation and proteolysis, the structure of calcium-depleted hCRP has, been determined by X-ray crystallography. Crystals of calcium-depleted, hCRP are invariably twinned and those suitable for analysis are merohedral, type II twins of point group 4 single crystals. The structure has been, solved by molecular replacement using the calcium-bound hCRP structure, [Shrive et al. (1996), Nature Struct. Biol. 3, 346-354]. It reveals two, independent pentamers which form a face-to-face decamer across a dyad, near-parallel to the twinning twofold axis. Cycles of intensity, deconvolution, density modification (tenfold NCS) and model building, eventually including refinement, give a final R factor of 0.19 (R(free) =, 0.20). Despite poor definition in some areas arising from the limited, resolution of the data and from the twinning and disorder, the structure, reveals the probable mode of twinning and the conformational changes, localized in one of the calcium-binding loops, which accompany calcium, binding.
DiseaseDisease
Known disease associated with this structure: Specific granule deficiency OMIM:[600749]
About this StructureAbout this Structure
1LJ7 is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
ReferenceReference
The three-dimensional structure of calcium-depleted human C-reactive protein from perfectly twinned crystals., Ramadan MA, Shrive AK, Holden D, Myles DA, Volanakis JE, DeLucas LJ, Greenhough TJ, Acta Crystallogr D Biol Crystallogr. 2002 Jun;58(Pt 6 Pt 2):992-1001. Epub, 2002 May 29. PMID:12037301
Page seeded by OCA on Mon Nov 12 18:01:54 2007