1QTJ
CRYSTAL STRUCTURE OF LIMULUS POLYPHEMUS SAP
Summary for 1QTJ
| Entry DOI | 10.2210/pdb1qtj/pdb |
| Related | 1GNH 1SAC |
| Descriptor | PROTEIN (SERUM AMYLOID P COMPONENT) (1 entity in total) |
| Functional Keywords | pentraxin fold, physiological doubly-stacked octamer, cyclic octamer, invertebrate lectin, sugar binding protein |
| Biological source | Limulus polyphemus (Atlantic horseshoe crab) |
| Total number of polymer chains | 2 |
| Total formula weight | 36971.45 |
| Authors | Shrive, A.K.,Metcalfe, A.M.,Cartwright, J.R.,Greenhough, T.J. (deposition date: 1999-06-28, release date: 2000-06-28, Last modification date: 2023-08-16) |
| Primary citation | Shrive, A.K.,Metcalfe, A.M.,Cartwright, J.R.,Greenhough, T.J. C-reactive protein and SAP-like pentraxin are both present in Limulus polyphemus haemolymph: crystal structure of Limulus SAP. J.Mol.Biol., 290:997-1008, 1999 Cited by PubMed Abstract: C-reactive protein and serum amyloid P component are members of the pentraxin family of oligomeric serum proteins which has been conserved through evolution. In humans both have pentameric structures and both play complex roles in the immune response, C-reactive protein being the classical acute-phase reactant produced in response to tissue damage and inflammation. An invertebrate SAP-like pentraxin has not previously been identified and it has been postulated that C-reactive protein and serum amyloid P component are products of a gene duplication event within vertebrate evolution. We have isolated serum amyloid P component from the haemolymph of the phylogenetically ancient "living fossil", the horseshoe crab Limulus polyphemus and determined the three-dimensional structure by X-ray crystallography. The structure of the previously undiscovered Limulus serum amyloid P component, the first invertebrate lectin structure to be determined, reveals the pentraxin fold and a novel doubly stacked octameric ring. The crystal structure and the discovery that both prototypic pentraxins are present in Limulus raises the possibility that both were present in the common ancestors of arthropods and chordates over 500 million years ago. The impact of the results on our understanding of the origins and evolution of pentraxins and innate immunity is discussed. PubMed: 10438598DOI: 10.1006/jmbi.1999.2956 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (3 Å) |
Structure validation
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