Disease relevance of tonB

• Molecular characterization of eutF mutants of Salmonella typhimurium LT2 identifies eutF lesions as partial-loss-of-function tonB alleles [1].
• In this respect the mechanism is distinct from a previously described Serratia marcescens system (sfuABC); the presence of the cloned sfuABC genes mediated tonB-independent uptake by S. typhimurium of iron complexed with alpha-ketoacids [2].
• The SapABCDF system constitutes a novel transporter for enteric bacteria and the first one harboring a periplasmic component with a role in virulence [3].
• Phage Gifsy-2 carries the sodC gene for a periplasmic [Cu,Zn]-superoxide dismutase previously implicated in the bacterial defences against killing by macrophages [4].
• In order to examine the structure on the periplasmic side of the membrane, we analyzed the MS ring complexes of Salmonella typhimurium overproduced in the cytoplasmic membrane of Escherichia coli [5].

High impact information on tonB

• These observations suggest that SOD protects periplasmic or inner membrane targets by diverting superoxide and limiting peroxynitrite formation, and they demonstrate the ability of the respiratory burst and nitric oxide synthase to synergistically kill microbial pathogens in vivo [6].
• All six mutations changed one or the other of the two cysteine residues in the mature protein to tyrosine, suggesting that these residues are involved in the release of protein into the periplasmic space, most likely by affecting protein folding [7].
• ATP-binding sites in the membrane components of histidine permease, a periplasmic transport system [8].
• In addition, undecaprenol-linked O antigen was detectable at the periplasmic face of the inner membrane within 30 sec after addition of galactose to a galE deep rough double mutant, and it accumulated stably in that location [9].
• O-reactive lipopolysaccharide appeared rapidly at the exposed periplasmic face of the inner membrane after addition of galactose and was rapidly depleted upon termination of the pulse [9].

Chemical compound and disease context of tonB

• A component of the high-affinity histidine transport system in Salmonella typhimurium, the periplasmic histidine-binding protein J, interacts with another transport component, the P protein [10].
• The 1.9 A x-ray structure of a closed unliganded form of the periplasmic glucose/galactose receptor from Salmonella typhimurium [11].
• Purification and characterization of the periplasmic lysine-, arginine-, ornithine-binding protein (LAO) from Salmonella typhimurium [12].
• Citrate transport in Salmonella typhimurium involves inducible periplasmic components [13].
• Formaldehyde and photoactivatable cross-linking of the periplasmic binding protein to a membrane component of the histidine transport system of Salmonella typhimurium [14].

Biological context of tonB

• Deletion mapping and three-factor cross analysis results are consistent with the gene order cobA trp eutF tonB at 34 min on the linkage map [15].
• The molecular characterization of the mutation that corrected the Eut- phenotype caused by allele Delta903 showed that the new mutation was a deletion of two nucleotides at the tonB-trpA fusion site [1].
• We cloned and characterized this operon from Salmonella typhimurium, as well as the flanking genes, tonB, ana and a new gene, cwd, which affects cell wall synthesis [16].
• Two periplasmic transport proteins which interact with a common membrane receptor show extensive homology: complete nucleotide sequences [17].
• S. typhimurium also appears to lack a periplasmic binding protein for vitamin B6 [18].

Anatomical context of tonB

• Periplasmic permeases consist of a substrate-binding receptor, located in the periplasm, and a membrane-bound complex composed of two integral membrane proteins and two nucleotide-binding proteins [19].
• TtrA and TtrB are predicted to be anchored by TtrC to the periplasmic face of the cytoplasmic membrane implying a periplasmic site for tetrathionate reduction [20].
• Novel periplasmic and cytoplasmic structural modules of the bases of bacterial flagella have been observed in situ and isolated using new biochemical protocols [21].
• Murine peritoneal macrophages mediated phagocytic processing of viable S. typhimurium expressing fusion proteins of the HEL epitope for presentation via I-Ak regardless of the bacterial compartment in which the epitope was contained (i.e., surface exposed, facing the periplasmic space, or in the cytoplasm) [22].
• Salmonella enterica serovar Typhimurium periplasmic superoxide dismutases SodCI and SodCII are required for protection against the phagocyte oxidative burst [23].

Associations of tonB with chemical compounds

• However, prolonged incubation of the siderophore-deficient S. typhimurium strain enb-7 under conditions of high iron stress resulted in significant delayed bacterial growth, promoted by tonB-dependent uptake of iron complexed with the high accumulated levels of pyruvic acid and other alpha-keto acids [24].
• Evidence for transient localization of newly synthesized lipopolysaccharide at the periplasmic face of the inner membrane has been obtained by immunoelectron microscopic techniques [9].
• The transmembrane signal, which is transmitted from the periplasmic aspartate-binding domain to the cytoplasmic regulatory domain, is carried by an intramolecular conformational change within the homodimeric receptor structure [25].
• Three-dimensional structures of the periplasmic lysine/arginine/ornithine-binding protein with and without a ligand [26].
• Two periplasmic binding proteins, HisJ and LAO, which are involved in histidine and arginine transport, respectively, have been crystallized [27].

Physical interactions of tonB

• The Salmonella typhimurium periplasmic histidine-binding J-protein is one of four proteins encoded by the histidine transport operon [28].

Other interactions of tonB

• All opp mutants, independently isolated by a variety of means, mapped at this one locus, between tonB and galU [29].
• A new class of cobalamin transport mutants (btuF) provides genetic evidence for a periplasmic binding protein in Salmonella typhimurium [30].
• Thus tctI encodes four proteins, one periplasmic, two integral, and one peripheral to the cytoplasmic membrane, with the genes arranged as tctA tctB tctC tctD [31].
• Here we show that the hilA regulators RtsA, HilD, and HilC can each induce transcription of dsbA, which encodes a periplasmic disulfide bond isomerase [32].
• The structural gene for the periplasmic glutamine-binding protein, glnH, was identified, as was a gene argT that probably encodes the structure of the lysine-arginine-ornithine-binding protein [33].

Analytical, diagnostic and therapeutic context of tonB

• Iron-responsive genes included iron transporters, iron storage and mobility proteins, iron-containing proteins (redox proteins, oxidoreductases, and cytochromes), transcriptional regulators, and the energy transducer tonB [34].
• Periplasmic nonspecific acid phosphatase II from Salmonella typhimurium LT2. Crystallization, detergent reactivation, and phosphotransferase activity [35].
• Variation of Brucella abortus 2308 infection in BALB/c mice induced by prior vaccination with salt-extractable periplasmic proteins from Brucella abortus 19 [36].
• Therefore, certain alterations that map to the ToxR cytoplasmic DNA binding domain, to the periplasmic domain, or to ToxS separate DNA binding activity from activator function [37].
• Amplification of bacterial genomic DNA by the polymerase chain reaction and direct sequencing after asymmetric amplification: application to the study of periplasmic permeases [38].

References