Resemblance of Carbocycle Formation from Carbohydrates between Archaea and Eucarya/Eubacteria.Biosynthesis of Calditol,the Characteristic Lipid-Content Molecule in Sulfolobus acidocaldarius

摘要

We investigated the biosynthesis of the unique structure of calditol,a part of the characteristic lipid molecules in the major part of thermophilic archaea,Sulfolobus sp.Deuterium-labeling experiments with deuterated glucose substrates,were carried out.The results clarified that calditol was biosynthesized from glucose with C-C bond formation between C-l and C-5,and no loss of deuterium at C-6 of glucose was observed.Two reaction mechanisms were possible when these experimental findings,and conventional reports were considered.Among these,the course* that assumes C-4 oxidation as the starting point would be preferable from the resemblance to myo-inositol biosynthesis.Furthermore,the high deuterium incorporation at C-l of calditol from C-l of glucose suggests that activation,such as oxidation at C-l,is not involved in the ether C-O bonding.