Osmotic shock induces the presence of glycocardiolipin in the purple membrane of Halobacterium salinarum.
In the purple membrane (PM) of Halobacterium salinarum is present a phospholipid dimer consisting of sulfo-triglycosyl-diether (S-TGD-1) esterified to the phosphate group of phosphatidic acid (PA), i.e., S-TGD-1-PA, called glycocardiolipin (GlyC) (Corcelli, A., M. Colella, G. Mascolo, F. P. Fanizzi, and M. Kates. A novel glycolipid and phospholipid in the purple membrane. 2000. Biochemistry. 39: 3318-3326). The GlyC content of whole cells, PM, and other cell fractions of H. salinarum have been analyzed. GlyC is a nonabundant phospholipid in H. salinarum cells, and it represents one of the major phospholipids of isolated PM. In this report, we show that a) GlyC is formed during the isolation of PM, b) GlyC increase in H. salinarum cells is specifically induced by osmotic shock, and c) in correspondence with GlyC increase, a decrease of S-TGD-1 levels occurs. The changes in membrane lipid composition observed during the isolation of PM are due to de novo synthesis of GlyC from S-TGD-1.
Lobasso
Simona
S
Dipartimento di Fisiologia Generale ed Ambientale and Dipartimento di Chimica, Università di Bari, via Amendola 165/a, 70126 Bari, Italy.
Lopalco
Patrizia
P
Lattanzio
Veronica M T
VM
Corcelli
Angela
A
D002308:Cardiolipins / Q000096:biosynthesis* / Q000737:chemistry; D002855:Chromatography, Thin Layer; D019617:Halobacterium salinarum / Q000166:cytology / Q000378:metabolism*; D050356:Lipid Metabolism; D015394:Molecular Structure; D009997:Osmotic Pressure; D018717:Purple Membrane / Q000378:metabolism*
D002308:Cardiolipins