Transverse and lateral distribution of phospholipids and glycolipids in the membrane of the bacterium Micrococcus luteus

作者：Jacqueline de BONY, Alfonso López, Martine Gilleron, Michèle Welby, Gilbert Lanéelle, Bernard Rousseau, Jean Pierre Beaucourt, Jean‐François Tocanne · 发表于：Biochemistry · 年份：1989 · DOI：10.1021/bi00435a016 · 被引用次数：59 · 研究领域：Lipid Membrane Structure and Behavior、Glycosylation and Glycoproteins Research、Bacterial Genetics and Biotechnology

The photodimerization of anthracene was used to investigate the transverse and lateral distribution of lipids in the membrane of the Gram-positive bacterium Micrococcus luteus. 9-(2-Anthryl)nonanoic acid (9-AN) is incorporated at a high rate into various membrane lipids of M. luteus. On irradiation of intact bacteria at 360 nm, anthracene-labeled lipids form stable photodimers which can be extracted and separated by thin-layer chromatography. We present here the results of a study on the distribution of two major lipids, phosphatidylglycerol (PG) and dimannosyldiacylglycerol (DMDG), within each leaflet of the membrane lipid bilayer. After metabolic incorporation of a tritiated derivative of 9-AN in M. luteus, the radioactivity associated with the photodimers issued from PG and DMDG was counted. In the bacterial membrane, the ratio of PG-DMDG heterodimer with respect to PG-PG and DMDG-DMDG homodimers is around half of what should be obtained for a homogeneous mixture of the two lipids. In order to find out whether this was due to an asymmetric distribution of the two lipids between the two membrane leaflets or a heterogeneous distribution of the two lipids within the same membrane leaflet, the transverse distribution of PG and DMDG was also investigated. This was carried out by following the kinetics of oxidation of the two lipids by periodic acid in the membrane of M. luteus protoplasts. PG predominated slightly in the outer layer (60%), while DMDG was found to be symmetrical...