Sites of phospholipid biosynthesis during induction of intracytoplasmic membrane formation in Rhodopseudomonas sphaeroides.
A rapid, gratuitous and cell-division uncoupled induction of intracytoplasmic photosynthetic membrane formation was demonstrated in low-aeration suspensions of chemotrophically grown Rhodopseudomonas sphaeroides. Despite a nearly 2-fold increase in phospholipid levels, no significant increases were detected in the specific activities of CDP-1,2-diacyl-sn-glycerol:sn-glycerol-3-phosphate phosphatidyltransferase (phosphatidylglycerophosphate synthase, EC 2.7.8.5) and CDP-1,2-diacyl-sn-glycerol:L-serine O-phosphatidyltransferase (phosphatidylserine synthase, EC 2.7.8.8), the first committed enzymes of anionic and zwitterionic phospholipid biosyntheses, respectively. The distribution of phosphatidylglycerophosphate and phosphatidylserine synthase activities after rate-zone sedimentation of cell-free extracts indicated that intracytoplasmic membrane phospholipids were synthesized mainly within distinct domains of the conserved cytoplasmic membrane. Labeling studies with 32Pi and L-[3H]phenylalanine suggested that preexisting phospholipid was utilized initially as the matrix for insertion of intracytoplasmic membrane protein that was synthesized and assembled de novo during induction.
D010717:CDPdiacylglycerol-Serine O-Phosphatidyltransferase / Q000378:metabolism; D007425:Intracellular Membranes / Q000378:metabolism; D008563:Membrane Lipids / Q000096:biosynthesis*; D010715:Phosphatidylglycerols / Q000096:biosynthesis; D010718:Phosphatidylserines / Q000096:biosynthesis; D010743:Phospholipids / Q000096:biosynthesis* / Q000302:isolation & purification; D010770:Phosphotransferases / Q000378:metabolism; D012242:Rhodobacter sphaeroides / Q000201:enzymology / Q000378:metabolism*; D017855:Transferases (Other Substituted Phosphate Groups)
D008563:Membrane Lipids; D010715:Phosphatidylglycerols; D010718:Phosphatidylserines; D010743:Phospholipids; C034358:phosphatidylglycerophosphate; D010770:Phosphotransferases; D017855:Transferases (Other Substituted Phosphate Groups); C020676:CDP-diacylglycerol-glycerol-3-phosphate 3-phosphatidyltransferase; D010717:CDPdiacylglycerol-Serine O-Phosphatidyltransferase