1.C.92 The Pentraxin (Pentraxin) Family

The pentraxins are a family of highly conserved plasma proteins of metazoans known to function in immune defence. The canonical members, C-reactive protein and serum amyloid P component, have been identified in arthropods and humans. Mammalian pentraxins are known to bind lipid bilayers, and a pentraxin representative from the American horseshoe crab, Limulus polyphemus, binds and permeabilizes mammalian erythrocytes. Both activities are Ca²⁺-dependent. Utilizing model liposomes and planar lipid bilayers, all of the Limulus pentraxins permeabilize lipid bilayers (Harrington et al., 2008). Mechanistically, Limulus C-reactive protein forms transmembrane pores in asymmetric planar lipid bilayers that mimic the outer membrane of Gram-negative bacteria and exhibits a Ca²⁺-independent form of membrane binding that may be sufficient for pore formation.

The reaction catalzed by pentraxins is:

small molecules (in) small molecules (out)