Open AccessBiosynthesis of Salmonella Lipopolysaccharide
Author(s) -
Mühlradt Peter F.
Publication year - 1971
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1971.tb01209.x
Subject(s) - heptose , lipid a , lysozyme , ethanolamine , biochemistry , biosynthesis , chemistry , phosphate , lysis , spheroplast , enzyme , lipopolysaccharide , biology , mutant , escherichia coli , gene , endocrinology
Several transfer reactions involved in the biosynthesis of the core part of Salmonella lipopolysaccharide have been studied in a cell free system. This system contained three components: (1) enzymes which were solubilised by repeated washings of EDTA‐lysozyme spheroplasts; (2) acceptor which consisted of either a heated cell wall fraction sedimenting at 20 000 x g , or heated, partially lysed, EDTA‐lysozyme treated cells; and (3) radioactively labelled precursors ([ 32 P]ATP, UDP‐[ 14 C]Glc, UDP‐[ 14 C]Gal). The following results were obtained with this transfer system: (1) only the γ‐phosphate group of ATP is transferred to the heptose moiety of the core; (2) polyphosphate which is synthesised enzymatically in a a side‐reaction by the system is not involved in the heptose phosphorylation; (3) there is a definite sequence of addition of the core substituents glucose, phosphate, and galactose to the incomplete core stub. This sequence is as follows: (Hep) 2 ‐(KDO, ethanolamine, phosphate, lipid A) → Glc‐(Hep) 2 ‐(KDO, ethanolamine, phosphate, lipid A) → Glc‐(Hep) 2 P‐(KDO, ethanolamine, phosphate, lipid A) → (Gal) 2 ‐Glc‐(Hep) 2 P ‐(KDO, ethanolamine, phosphate, lipid A).