The Interaction Between α-enolase Of Staphylococcus Aureu And Lipoprotein (a)

Plasminogen (Plg) via its lysine binding sites (LBS) can bind to Plg receptors on the surface of Staphylococcus aureus, subsequently being converted to plasmin by host and/or bacterial plasminogen activators. Bacterial cell-bound plasmin contributes to the spreading of S. aureus across tissue barriers. Lp(a) contains an apoliporotein(a) [Apo(a)] and a LDL. Apo(a) and Plg have a high similarity and both of them contain Kringle (K) domains which contain LBS, of which KIV10 of Apo(a) contains a strong LBS. a-enolase is thought to be one of Plg receptors on the surface of S. aureus. Therefore, it's possible that Lp(a) may bind to on the surface of S. aureus and competitively inhibits the binding of Plg to S. aureus.In this paper, the interactions of recombinant a-enolase (rEno) and its C-terminal lysine residue-truncated variant (rEnoA434) with Lp(a) and recombinant KIV10 (rKIV10) were studied.After induction with anhydrotetracycline the rEno, rEnoA434 and rKIV10was purified by the affinity chromatography. The binding of rEno, rEnoA434 to Plg, Lp(a), LDL and rKIV10 was detected by enzyme-linked immunosorbent assay (ELISA) and affinity chromatography-binding assay followed by Western blot analysis. The result showed that rEno, rEnoA434 could specifically bind to Plg, Lp(a) and rKIV10 but not to LDL. In addition, EACA could significantly inhibit their binding. The binding of rEno to Plg, Lp(a) is stronger than rEnoΔ434. Taken together, it can be supposed that Lp(a) via its LBS bind to rEno, rEnoΔ434, furthermore, the C-terminal lysine residue of rEno plays a role in the binding.