2omb
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Bence Jones KWR Protein- Immunoglobulin Light Chain Dimer, P3(1)21 Crystal Form
OverviewOverview
A Bence Jones protein isolated in the early 1960s from a patient (initials, KWR) suffering from plasma-cell dyscrasia was crystallized and its, structure was analyzed in four different unit cells by X-ray diffraction., The final models of the molecule in all crystal forms were virtually the, same, although the elbow angles relating the constant and variable domains, of the Bence Jones dimers varied over a range of 10 degrees . The, tetragonal form had an R factor of 22.6% and an R(free) of 28.3% at 2.2 A, resolution. Phosphate or sulfate ions (depending on the crystallization, conditions) were found in the antigen-combining sites in all crystals, as, well as an unidentified ligand tightly bound in the hydrophobic ;deep, pocket' beneath the antigen-binding site. The ligand was treated as a, phenol molecule. Two trigonal crystal forms were among those solved. One, was grown at pH 4.0 and the other was only obtained after sitting for more, than eight months at room temperature. The latter crystal was composed of, molecules that were degraded in their constant domains. Both low pH and, proteolytic degradation of constant domains are known to promote the, polymerization of some Bence Jones proteins into amyloid fibrils. Indeed, in both trigonal crystal forms the molecules are organized with, pseudo-hexagonal symmetry about the unique crystallographic axes in a, manner suggestive of such fibrils. The arrangement of Bence Jones dimers, is also consistent with other observations regarding Bence Jones, amyloid-fibril structure and current models.
About this StructureAbout this Structure
2OMB is a Protein complex structure of sequences from Homo sapiens with and as ligands. Full crystallographic information is available from OCA.
ReferenceReference
Bence Jones KWR protein structures determined by X-ray crystallography., Makino DL, Henschen-Edman AH, Larson SB, McPherson A, Acta Crystallogr D Biol Crystallogr. 2007 Jul;63(Pt 7):780-92. Epub 2007, Jun 15. PMID:17582169
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