Cardiolipin is an Optimal Phospholipid for the Assembly, Stability, and Proper Functionality of the Dimeric Form of NhaA Na+/H+ Antiporter

• Published in: Scientific reports Vol. 9; no. 1; pp. 17662 - 11
• Main Authors: Rimon, Abraham, Mondal, Ramakanta, Friedler, Assaf, Padan, Etana
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 27.11.2019; Nature Publishing Group
• Subjects: 631/1647; 631/45; 82; Binding Sites; Cardiolipin; Cardiolipins - metabolism; Cardiolipins - pharmacology; Drug development; E coli; Escherichia coli Proteins - chemistry; Escherichia coli Proteins - metabolism; Glycerol; Humanities and Social Sciences; Humans; Hydrogen; Monomers; multidisciplinary; Na+/H+-exchanging ATPase; Phospholipids; Phospholipids - metabolism; Protein Multimerization - drug effects; Science; Science (multidisciplinary); Sodium-Hydrogen Exchangers - chemistry; Sodium-Hydrogen Exchangers - metabolism
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-019-54198-8

Cardiolipin (CL) was shown to bound to the dimer interface of NhaA Na + /H + antiporter. Here, we explore the cardiolipin-NhaA interaction both in vitro and in vivo . Using a novel and straightforward in-vitro assay in which n-dodecyl β-D maltoside (DDM) detergent is used to delipidate the dimer interface and to split the dimers into monomers; the monomers are subsequently exposed to cardiolipin or the other E. coli phospholipids. Most efficient reconstitution of dimers is observed by cardiolipin. This assay is likely to be applicable to future studies of protein–lipid interactions. In-vivo experiments further reveal that cardiolipin is necessary for NhaA survival. Although less efficient phosphatidyl-glycerol (PG) can also reconstitute NhaA monomers to dimers. We also identify a putative cardiolipin binding site. Our observations may contribute to drug design, as human NhaA homologues, which are involved in severe pathologies, might also require specific phospholipids.