Septal localization by membrane targeting sequences and a conserved sequence essential for activity at the COOH-terminus of Bacillus subtilis cardiolipin synthase.

摘要: The acidic phospholipid cardiolipin (CL) is localized on polar and septal membranes plays an important physiological role in Bacillus subtilis cells. ClsA, the enzyme responsible for CL synthesis, also membranes. We found that GFP fusion proteins of with NH2-terminal internal deletions retained localization. However, derivatives starting from COOH-terminus (Leu482) ceased to localize septum once deletion passed Ile residue at 448, indicating sequence localization confined within a short distance COOH-terminus. Two sequences, Ile436-Leu450 Leu466-Leu478, are predicted individually form amphipathic α-helix. This configuration known as membrane targeting (MTS) we therefore refer them MTS2 MTS1, respectively. Either one has ability affect localization, each these sequences by itself localizes septum. Membrane association constructs this containing MTSs was verified subcellular fractionation contrast, abolished after deleting just last residue, Leu482, COOH-terminal four amino acid sequence, Ser-Pro-Ile-Leu, which highly conserved among bacterial synthases.