title: Site of ATPase activity in Myxococcus xanthus: lipid requirement for enzyme activity. Dedicated to Professor Dr. W. Schwartz on his 80th birthday.
abstract: Treatment of cells with lysophosphatidylcholine, lysozyme, and phospholipase D removed most of their phospholipids and reduced ATPase activity to near zero. Addition of a microdispersion of phospholipids restored enzyme activity to various degrees. Phosphatidylcholine was most effective in reconstitution experiments, less effective were phosphatidylethanolamine and phosphatidylserine. Lipid analyses of cell fractions were possible through separation of cell wall and cell membrane in a sucrose gradient after differentiated treatment of glutaraldehyde fixed cells with lysophosphatidylcholine, lysozyme, and pronase. Phosphatidylcholine was almost exclusively a component of the cell membrane, whereas phosphatidylethanolamine was that of the wall. It is concluded that lipids are necessary for in vivo function of a Mg-dependent ATPase, and that membrane-associated phosphatidylcholine may serve as a matrix for the enzyme. Lipid extracts made from cells or cell fractions contained plasmologens, not previously reported to occur in Gram-negative, aerobic bacteria.
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism*; D002462:Cell Membrane / Q000201:enzymology; D004789:Enzyme Activation; D050356:Lipid Metabolism; D008244:Lysophosphatidylcholines / Q000494:pharmacology; D008274:Magnesium / Q000378:metabolism; D008563:Membrane Lipids / Q000378:metabolism; D009113:Muramidase / Q000494:pharmacology; D009231:Myxococcales / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism; D010713:Phosphatidylcholines / Q000378:metabolism; D010740:Phospholipases / Q000494:pharmacology; D010743:Phospholipids / Q000378:metabolism
chemical_list: D008244:Lysophosphatidylcholines; D008563:Membrane Lipids; D010713:Phosphatidylcholines; D010743:Phospholipids; D010740:Phospholipases; D009113:Muramidase; D000251:Adenosine Triphosphatases; D008274:Magnesium