The lipid A 1-phosphatase of Helicobacter pylori is required for resistance to the antimicrobial peptide polymyxin

An X. Tran, Judy D. Whittimore, Priscilla B. Wyrick, Sara C. McGrath, Robert J. Cotter, M. Stephen Trent

Research output: Contribution to journalArticle

Abstract

Modification of the phosphate groups of lipid A with amine-containing substituents, such as phosphoethanolamine, reduces the overall net negative charge of gram-negative bacterial lipopolysaccharide, thereby lowering its affinity to cationic antimicrobial peptides. Modification of the 1 position of Helicobacter pylori lipid A is a two-step process involving the removal of the 1-phosphate group by a lipid A phosphatase, LpxEHP (Hp0021), followed by the addition of a phosphoethanolamine residue catalyzed by EptAHP (Hp0022). To demonstrate the importance of modifying the 1 position of H. pylori lipid A, we generated LpxEHP-deficient mutants in various H. pylori strains by insertion of a chloramphenicol resistance cassette into IpxEHP and examined the significance of LpxE with respect to cationic antimicrobial peptide resistance. Using both mass spectrometry analysis and an in vitro assay system, we showed that the loss of LpxEHP activity in various H. pylori strains resulted in the loss of modification of the 1 position of H. pylori lipid A, thus confirming the function of LpxEHP. Due to its unique lipid A structure, H. pylori is highly resistant to the antimicrobial peptide polymyxin (MIC > 250 μg/ml). However, disruption of lpxEHP in H. pylori results in a dramatic decrease in polymyxin resistance (MIC, 10 μg/ml). In conclusion, we have characterized the first gram-negative LpxE-deficient mutant and have shown the importance of modifying the 1 position of H. pylori lipid A for resistance to polymyxin.

Original languageEnglish (US)
Pages (from-to)4531-4541
Number of pages11
JournalJournal of Bacteriology
Volume188
Issue number12
DOIs
StatePublished - Jun 2006

Fingerprint

Polymyxins
Lipid A
Phosphoric Monoester Hydrolases
Helicobacter pylori
Peptides
Antimicrobial Cationic Peptides
Phosphates
Chloramphenicol Resistance
Amines
Lipopolysaccharides
Mass Spectrometry

ASJC Scopus subject areas

  • Applied Microbiology and Biotechnology
  • Immunology

Cite this

The lipid A 1-phosphatase of Helicobacter pylori is required for resistance to the antimicrobial peptide polymyxin. / Tran, An X.; Whittimore, Judy D.; Wyrick, Priscilla B.; McGrath, Sara C.; Cotter, Robert J.; Trent, M. Stephen.

In: Journal of Bacteriology, Vol. 188, No. 12, 06.2006, p. 4531-4541.

Research output: Contribution to journalArticle

Tran, An X. ; Whittimore, Judy D. ; Wyrick, Priscilla B. ; McGrath, Sara C. ; Cotter, Robert J. ; Trent, M. Stephen. / The lipid A 1-phosphatase of Helicobacter pylori is required for resistance to the antimicrobial peptide polymyxin. In: Journal of Bacteriology. 2006 ; Vol. 188, No. 12. pp. 4531-4541.
@article{8178e4934b184c279296d31a46857094,
title = "The lipid A 1-phosphatase of Helicobacter pylori is required for resistance to the antimicrobial peptide polymyxin",
abstract = "Modification of the phosphate groups of lipid A with amine-containing substituents, such as phosphoethanolamine, reduces the overall net negative charge of gram-negative bacterial lipopolysaccharide, thereby lowering its affinity to cationic antimicrobial peptides. Modification of the 1 position of Helicobacter pylori lipid A is a two-step process involving the removal of the 1-phosphate group by a lipid A phosphatase, LpxEHP (Hp0021), followed by the addition of a phosphoethanolamine residue catalyzed by EptAHP (Hp0022). To demonstrate the importance of modifying the 1 position of H. pylori lipid A, we generated LpxEHP-deficient mutants in various H. pylori strains by insertion of a chloramphenicol resistance cassette into IpxEHP and examined the significance of LpxE with respect to cationic antimicrobial peptide resistance. Using both mass spectrometry analysis and an in vitro assay system, we showed that the loss of LpxEHP activity in various H. pylori strains resulted in the loss of modification of the 1 position of H. pylori lipid A, thus confirming the function of LpxEHP. Due to its unique lipid A structure, H. pylori is highly resistant to the antimicrobial peptide polymyxin (MIC > 250 μg/ml). However, disruption of lpxEHP in H. pylori results in a dramatic decrease in polymyxin resistance (MIC, 10 μg/ml). In conclusion, we have characterized the first gram-negative LpxE-deficient mutant and have shown the importance of modifying the 1 position of H. pylori lipid A for resistance to polymyxin.",
author = "Tran, {An X.} and Whittimore, {Judy D.} and Wyrick, {Priscilla B.} and McGrath, {Sara C.} and Cotter, {Robert J.} and Trent, {M. Stephen}",
year = "2006",
month = "6",
doi = "10.1128/JB.00146-06",
language = "English (US)",
volume = "188",
pages = "4531--4541",
journal = "Journal of Bacteriology",
issn = "0021-9193",
publisher = "American Society for Microbiology",
number = "12",

}

TY - JOUR

T1 - The lipid A 1-phosphatase of Helicobacter pylori is required for resistance to the antimicrobial peptide polymyxin

AU - Tran, An X.

AU - Whittimore, Judy D.

AU - Wyrick, Priscilla B.

AU - McGrath, Sara C.

AU - Cotter, Robert J.

AU - Trent, M. Stephen

PY - 2006/6

Y1 - 2006/6

N2 - Modification of the phosphate groups of lipid A with amine-containing substituents, such as phosphoethanolamine, reduces the overall net negative charge of gram-negative bacterial lipopolysaccharide, thereby lowering its affinity to cationic antimicrobial peptides. Modification of the 1 position of Helicobacter pylori lipid A is a two-step process involving the removal of the 1-phosphate group by a lipid A phosphatase, LpxEHP (Hp0021), followed by the addition of a phosphoethanolamine residue catalyzed by EptAHP (Hp0022). To demonstrate the importance of modifying the 1 position of H. pylori lipid A, we generated LpxEHP-deficient mutants in various H. pylori strains by insertion of a chloramphenicol resistance cassette into IpxEHP and examined the significance of LpxE with respect to cationic antimicrobial peptide resistance. Using both mass spectrometry analysis and an in vitro assay system, we showed that the loss of LpxEHP activity in various H. pylori strains resulted in the loss of modification of the 1 position of H. pylori lipid A, thus confirming the function of LpxEHP. Due to its unique lipid A structure, H. pylori is highly resistant to the antimicrobial peptide polymyxin (MIC > 250 μg/ml). However, disruption of lpxEHP in H. pylori results in a dramatic decrease in polymyxin resistance (MIC, 10 μg/ml). In conclusion, we have characterized the first gram-negative LpxE-deficient mutant and have shown the importance of modifying the 1 position of H. pylori lipid A for resistance to polymyxin.

AB - Modification of the phosphate groups of lipid A with amine-containing substituents, such as phosphoethanolamine, reduces the overall net negative charge of gram-negative bacterial lipopolysaccharide, thereby lowering its affinity to cationic antimicrobial peptides. Modification of the 1 position of Helicobacter pylori lipid A is a two-step process involving the removal of the 1-phosphate group by a lipid A phosphatase, LpxEHP (Hp0021), followed by the addition of a phosphoethanolamine residue catalyzed by EptAHP (Hp0022). To demonstrate the importance of modifying the 1 position of H. pylori lipid A, we generated LpxEHP-deficient mutants in various H. pylori strains by insertion of a chloramphenicol resistance cassette into IpxEHP and examined the significance of LpxE with respect to cationic antimicrobial peptide resistance. Using both mass spectrometry analysis and an in vitro assay system, we showed that the loss of LpxEHP activity in various H. pylori strains resulted in the loss of modification of the 1 position of H. pylori lipid A, thus confirming the function of LpxEHP. Due to its unique lipid A structure, H. pylori is highly resistant to the antimicrobial peptide polymyxin (MIC > 250 μg/ml). However, disruption of lpxEHP in H. pylori results in a dramatic decrease in polymyxin resistance (MIC, 10 μg/ml). In conclusion, we have characterized the first gram-negative LpxE-deficient mutant and have shown the importance of modifying the 1 position of H. pylori lipid A for resistance to polymyxin.

UR - http://www.scopus.com/inward/record.url?scp=33744975276&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=33744975276&partnerID=8YFLogxK

U2 - 10.1128/JB.00146-06

DO - 10.1128/JB.00146-06

M3 - Article

C2 - 16740959

AN - SCOPUS:33744975276

VL - 188

SP - 4531

EP - 4541

JO - Journal of Bacteriology

JF - Journal of Bacteriology

SN - 0021-9193

IS - 12

ER -