Sites of phospholipid biosynthesis during induction of intracytoplasmic membrane formation in Rhodopseudomonas sphaeroides

• Published in: Archives of microbiology 1985-07, Vol.142 (2), p.136-140
• Main Authors: RADCLIFFE, C. W, BROGLIE, R. M, NIEDERMAN, R. A
• Format: Article
• Language: English
• Subjects: Bacteriology; Biogenesis of cell structures, supramolecular organization; Biological and medical sciences; CDPdiacylglycerol-Serine O-Phosphatidyltransferase - metabolism; Fundamental and applied biological sciences. Psychology; Intracellular Membranes - metabolism; Membrane Lipids - biosynthesis; Microbiology; Phosphatidylglycerols - biosynthesis; Phosphatidylserines - biosynthesis; Phospholipids - biosynthesis; Phospholipids - isolation & purification; Phosphotransferases - metabolism; Rhodobacter sphaeroides - enzymology; Rhodobacter sphaeroides - metabolism; Transferases (Other Substituted Phosphate Groups)
• ISSN: 0302-8933; 1432-072X
• DOI: 10.1007/BF00447056

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.