Lipid A biosynthesis in Rhizobium leguminosarum: Role of a 2-keto-3-deoxyoctulosonate-activated 4{prime} phosphatase
- Univ. of Georgia, Athens, GA (United States); and others
Lipid A from several strains of the N{sub 2}-fixing bacterium Rhizobium leguminosarum displays significant structural differences from Escherichia coli lipid A, one of which is the complete absence of phosphate groups. However, the first seven enzymes of E. coli lipid A biosynthesis, leading from UDP-GlcNAc to the phosphorylated intermediate, 2-keto-3-deoxyoctulosonate (Kdo{sub 2})-lipid IV{sub A}, are present in R. leguminosarum. We now describe a membrane-bound phosphatase in R. leguminosarum extracts that removes the 4{prime} phosphate of Kdo{sub 2}-lipid IV{sub A}. The 4{prime} phosphatase is selective for substrates containing the Kdo domain. It is present in extracts of R. leguminosarum biovars phaseoli, viciae, and trifolii but is not detectable in E. coli and Rhizobium meliloti. A nodulation-defective strain (24AR) of R. leguminosarum bovar trifolii, known to contain a 4{prime} phosphate residue on its lipid A, also lacks measurable 4{prime} phosphatase activity. the Kdo-dependent 4{prime} phosphatase appears to be a key reaction in a pathway for generating phosphate-deficient lipid A.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 100195
- Journal Information:
- Proceedings of the National Academy of Sciences of the United States of America, Journal Name: Proceedings of the National Academy of Sciences of the United States of America Journal Issue: 16 Vol. 92; ISSN PNASA6; ISSN 0027-8424
- Country of Publication:
- United States
- Language:
- English
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