Lipid A Modifications Characteristic of Salmonella typhimurium Are Induced by NH4VO3 inEscherichia coli K12

Zhou, Zhimin; Lin, Shanhua; Cotter, Robert J.; Raetz, Christian R. H.

doi:10.1074/jbc.274.26.18503

Cited by 212 publications

(396 citation statements)

References 55 publications

(101 reference statements)

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“…In E. coli K-12, approximately two-thirds of the lipid A is a hexa-acylated disaccharide of glucosamine with monophosphate groups at positions 1 and 49 (1-O-P lipid A). The remainder contains a diphosphate moiety at position 1 (1-O-PP lipid A) (Zhou et al, 1999). A small amount of 1-dephosphorylated lipid A (identified herein as 1-OH) can be generated during the mild acid hydrolysis procedure.…”

Section: Methodsmentioning

confidence: 99%

“…two-thirds of the lipid A is a hexa-acylated disaccharide of glucosamine in which monophosphate groups are attached at positions 1 and 49 (1-O-P lipid A) (Zhou et al, 1999). The remaining one-third of lipid A contains a diphosphate moiety at position 1 (1-O-PP lipid A, Fig.…”

Section: Introductionmentioning

confidence: 99%

“…The remaining one-third of lipid A contains a diphosphate moiety at position 1 (1-O-PP lipid A, Fig. 1) (Zhou et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

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Phosphoethanolamine substitution in the lipid A of Escherichia coli O157 : H7 and its association with PmrC

et al. 2006

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This study shows that lipid A of Escherichia coli O157 : H7 differs from that of E. coli K-12 in that it has a phosphoform at the C-1 position, which is distinctively modified by a phosphoethanolamine (PEtN) moiety, in addition to the diphosphoryl form. The pmrC gene responsible for the addition of PEtN to the lipid A of E. coli O157 : H7 was inactivated and the changes in lipid A profiles were assessed. The pmrC null mutant still produced PEtN-modified lipid A species, albeit in a reduced amount, indicating that PmrC was not the only enzyme that could be used to add PEtN to lipid A. Natural PEtN substitution was shown to be present in the lipid A of other serotypes of enterohaemorrhagic E. coli and absent from the lipid A of E. coli K-12. However, the cloned pmrC O157 gene in a high-copy-number plasmid generated a large amount of PEtN-substituted lipid A species in E. coli K-12. The occurrence of PEtN-substituted lipid A species was associated with a slight increase in the MICs of cationic peptide antibiotics, suggesting that the lipid A modification with PEtN would be beneficial for survival of E. coli O157 : H7 in certain environmental niches. However, PEtN substitution in the lipid A profiles was not detected when putative inner-membrane proteins (YhbX/YbiP/YijP/Ecf3) that show significant similarity with PmrC in amino acid sequence were expressed from high-copy-number plasmids in E. coli K-12. This suggests that these potential homologues are not responsible for the addition of PEtN to lipid A in the pmrC mutant of E. coli O157 : H7. When cells were treated with EDTA, the amount of palmitoylated lipid A from the cells carrying a high-copy-number plasmid clone of pmrC O157 that resulted in significant increase of PEtN substitution was unchanged compared with cells without PEtN substitution, suggesting that the PEtN moiety substituted in lipid A does not compensate for the loss of divalent cations required for bridging neighbouring lipid A molecules.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Phosphoethanolamine substitution in the lipid A of Escherichia coli O157 : H7 and its association with PmrC

et al. 2006

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“…All of these gene products except pmrM are essential for the biosynthesis of Ara4N-lipid A and for resistance to CAMPs (18). In vitro studies by Raetz and co-workers have shown a pathway for the biosynthesis of UDP-L-Ara4N from UDP-glucose (UDP-Glc) (19)(20)(21). The pathway begins with the oxidation of UDP-Glc to UDP-glucuronic acid (UDP-GlcA) catalyzed by the well-characterized UDP-Glc dehydrogenase (PmrE/Ugd) ( Figure 1).…”

mentioning

confidence: 99%

“…UDP-GlcA is then oxidatively decarboxylated by ArnA (PmrI) to yield UDP-4-keto-arabinose (UDPAra4O), which in turn is transaminated to produce UDP-4-amino-arabinose (UDP-Ara4N) in a reaction catalyzed by ArnB (PmrH). On the basis of sequence similarity to enzymes with known activities, additional gene products of the pmrHFIJKLM operon have been proposed to catalyze the transfer of Ara4N from the UDP intermediate to lipid A (19,(21)(22)(23)(24). The enzymes in this pathway are potential targets for antibacterial drug design.…”

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confidence: 99%

Crystal Structure ofEscherichia coliArnA (PmrI) Decarboxylase Domain. A Key Enzyme for Lipid A Modification with 4-Amino-4-deoxy-l-arabinose and Polymyxin Resistance^,

2004

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Gram-negative bacteria including Escherichia coli, Salmonella typhimurium, and Pseudomonas aeruginosa can modify the structure of lipid A in their outer membrane with 4-amino-4-deoxy-Larabinose (Ara4N). Such modification results in resistance to cationic antimicrobial peptides of the innate immune system and antibiotics such as polymyxin. ArnA is a key enzyme in the lipid A modification pathway, and its deletion abolishes both the Ara4N-lipid A modification and polymyxin resistance. ArnA is a bifunctional enzyme. It can catalyze (i) the NAD + -dependent decarboxylation of UDP-glucuronic acid to UDP-4-keto-arabinose and (ii) the N-10-formyltetrahydrofolatedependent formylation of UDP-4-amino-4-deoxy-L-arabinose. We show that the NAD + -dependent decarboxylating activity is contained in the 360 amino acid C-terminal domain of ArnA. This domain is separable from the N-terminal fragment, and its activity is identical to that of the full-length enzyme. The crystal structure of the ArnA decarboxylase domain from E. coli is presented here. The structure confirms that the enzyme belongs to the short-chain dehydrogenase/reductase (SDR) family. On the basis of sequence and structure comparisons of the ArnA decarboxylase domain with other members of the short-chain dehydrogenase/reductase (SDR) family, we propose a binding model for NAD + and UDP-glucuronic acid and the involvement of residues T 432 , Y 463 , K 467 ,R 619 , and S 433 in the mechanism of NAD + -dependent oxidation of the 4″-OH of the UDP-glucuronic acid and decarboxylation of the UDP-4-keto-glucuronic acid intermediate.In the process of establishing infections, bacteria must overcome the host defense mechanism including the bactericidal action of cationic antimicrobial peptides (CAMPs). 1 These are small, amphipathic, positively charged peptides that destroy bacteria through membrane permeabilization and constitute a phylogenetically conserved branch of the innate immune system (1-4). In the case of Gram-negative bacteria, CAMPs bind to the bacterial cell surface through electrostatic interactions with the negatively charged groups of the lipopolysaccharide (LPS), the immunogenic glycolipid in the outer membrane in Gram-negative bacteria (5,6). They then traverse to the inner membrane and form a pore, which leads to membrane permeabilization and cell death (7)(8)(9). In addition to their function as a key member of the innate immune system, CAMPs represent an important class of clinical antimicrobials. They have both intrinsic bactericidal activity and appear to enhance the activity of other antibiotics, presumably by facilitating their entry into the microbe (3,10,11 21). The N-terminal domain (residues 1-313) is similar in sequence to other enzymes involved in formyl transfer. However, the relevance of this reaction in the biosynthesis of Ara4N-lipid A is unclear. ArnA is also responsible for the C-4″ oxidation of UDP-GlcA to UDP-4-keto-glucuronic acid and its decarboxylation to yield UDP-4-keto-arabinose (boxed in Figure 1) (20). The C terminus o...

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On-probe sample purification of lipids for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

et al. 2000

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Lipid A Modifications Characteristic of Salmonella typhimurium Are Induced by NH4VO3 inEscherichia coli K12

Cited by 212 publications

References 55 publications

Phosphoethanolamine substitution in the lipid A of Escherichia coli O157 : H7 and its association with PmrC

Phosphoethanolamine substitution in the lipid A of Escherichia coli O157 : H7 and its association with PmrC

Crystal Structure ofEscherichia coliArnA (PmrI) Decarboxylase Domain. A Key Enzyme for Lipid A Modification with 4-Amino-4-deoxy-l-arabinose and Polymyxin Resistance^,

On-probe sample purification of lipids for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

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Lipid A Modifications Characteristic of Salmonella typhimurium Are Induced by NH4VO3 inEscherichia coli K12

Cited by 212 publications

References 55 publications

Phosphoethanolamine substitution in the lipid A of Escherichia coli O157 : H7 and its association with PmrC

Phosphoethanolamine substitution in the lipid A of Escherichia coli O157 : H7 and its association with PmrC

Crystal Structure ofEscherichia coliArnA (PmrI) Decarboxylase Domain. A Key Enzyme for Lipid A Modification with 4-Amino-4-deoxy-l-arabinose and Polymyxin Resistance,

On-probe sample purification of lipids for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

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About

Crystal Structure ofEscherichia coliArnA (PmrI) Decarboxylase Domain. A Key Enzyme for Lipid A Modification with 4-Amino-4-deoxy-l-arabinose and Polymyxin Resistance^,