Disease relevance of lpxL

• Sequencing, mutational analysis, and transcriptional regulation of the Escherichia coli htrB gene [1].
• Mutation of the htrB locus of Haemophilus influenzae nontypable strain 2019 is associated with modifications of lipid A and phosphorylation of the lipo-oligosaccharide [2].
• The htrB mutants initially showed temperature sensitivity, but they lost the sensitivity after a few passages at 30 degrees C and were able to grow at 37 degrees C. They also showed hypersensitivity to deoxycholate and kanamycin, which persisted on passage [2].
• Mutation of the htrB gene in a virulent Salmonella typhimurium strain by intergeneric transduction: strain construction and phenotypic characterization [3].
• The htrB gene product of Haemophilus influenzae contributes to the toxicity of the lipooligosaccharide [3].

High impact information on lpxL

• Membranes from the lpxP mutant MKV11 grown at 12 degrees C lacked the cold-induced palmitoleoyltransferase present in membranes of cold-shocked wild type cells but retained normal levels of the constitutive lauroyltransferase encoded by lpxL [4].
• Recently, a gene displaying 54% identity and 73% similarity at the protein level to lpxL was found in the genome of E. coli [5].
• Mass spectrometric analysis of the lipid A of the htrB mutant indicated a loss of one or both myristic acid substitutions [2].
• In order to study the function of the HtrB protein in Haemophilus, we generated two isogenic htrB mutants by shuttle mutagenesis using a mini-Tn3 [2].
• The Escherichia coli htrB gene was originally discovered because its insertional inactivation led to an exquisitely temperature-sensitive phenotype in rich media, i.e. the ability to form colonies at temperatures below 32 degrees C, but not above 33 degrees C. The htrB gene has been sequenced [1].

Biological context of lpxL

• Isolation and characterization of the Escherichia coli htrB gene, whose product is essential for bacterial viability above 33 degrees C in rich media [6].

Associations of lpxL with chemical compounds

• Mass spectroscopic analysis has demonstrated that lipid A from an H. influenzae htrB mutant is predominantly tetraacyl and similar in structure to lipid IV(A), which has been shown to be nontoxic in animal models [3].
• The htrB gene encodes a 2-keto-3-deoxyoctulosonic acid-dependent acyltransferase which is responsible for myristic acid substitutions at the hydroxy moiety of lipid A beta-hydroxymyristic acid [3].

Other interactions of lpxL

• The htrB+ gene has been cloned by complementation and shown to reside at 23.4 min on the E. coli genetic map, the relative order of the neighboring loci being mboA-htrB-pyrC [6].
• Two genes homologous to lpxL and lpxM from Escherichia coli and other gram-negative bacteria, which are involved in lipid A acyloxyacylation, were identified in Neisseria meningitidis strain H44/76 and insertionally inactivated [7].

Analytical, diagnostic and therapeutic context of lpxL

• Northern blot analysis clearly shows that the monocistronic htrB message is not under heat-shock regulation [1].
• Immunoblotting analysis also showed that the LOS from the htrB mutants lost reactivity to a monoclonal antibody, 6E4, which binds to the wild type NTHi 2019 LOS [2].

References