Phospholipids of Rhizobium contain nodE-determined highly unsaturated fatty acid moieties.

摘要: In Rhizobium leguminosarum the nodABC and nod-FEL operons are involved in production of lipooligosaccharide signals, which mediate host specificity. A nodE-determined highly unsaturated C18:4 fatty acid (trans-2,trans-4,trans-6,cis-11-octadecatetraenoic acid) is essential for ability signals to induce nodule primordia (Spaink, H. P., Sheeley, D. M., van Brussel, A. N., Glushka, J., York, W.S., Tak, T., Geiger, O., Kennedy, E. Reinhold, V. Lugtenberg, B. J. (1991) Nature 354, 125-130) preinfection thread structures (van Bakhuizen, R., Spronsen, P. C., Spaink, Kijne, W. (1992) Science 257, 70-72) on plant Vicia sativa. We presently focus question how these lipo-oligosaccharide synthesized Rhizobium. Here we show that after induction nodFE genes, even absence trans-2,trans-4,trans-6,cis-11-octadecatetraenoic acid, has a characteristic absorbance maximum 303 nm, synthesized; this shows biosynthesis unusual not dependent synthesis lipooligosaccharides. This finding also suggests completed before it linked sugar backbone lipooligosaccharide. an attempt identify lipid fraction with associated, found sn-2 position phospholipids. Even when produced wild type cell, still bound all major These findings offer interesting possibilities. 1) The phospholipids might be biosynthetic intermediates 2) phospholipids, containing nodFE-derived acids, have signal function their own.