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2 edition of Membrane topology of Escherichia coli TonB protein found in the catalog.

Membrane topology of Escherichia coli TonB protein

Steven K. Roof

Membrane topology of Escherichia coli TonB protein

by Steven K. Roof.

by Steven K. Roof

  • 280 Want to read
  • 2 Currently reading

Published .
Written in English

    Subjects:
  • Escherichia coli -- Immunology.,
  • Carrier proteins.,
  • Cell membranes.

  • The Physical Object
    Paginationvii, 112 p. :
    Number of Pages112
    ID Numbers
    Open LibraryOL16909909M

    Energy-coupled transporters in the outer membrane of Escherichia coli and other Gram-negative bacteria allow the entry of scarce substrates, toxic proteins, and bacterial viruses (phages) into the cells. The required energy is derived from the proton-motive force of the cytoplasmic membrane, which is coupled to the outer membrane via the ExbB-ExbD-TonB protein complex. Knowledge of the.   Involved in the active translocation of vitamin B12 (cyanocobalamin) across the outer membrane to the periplasmic space. It derives its energy for transport by interacting with the trans-periplasmic membrane protein TonB. Is also a receptor for bacteriophages BF23 and C1, and for A .


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Membrane topology of Escherichia coli TonB protein by Steven K. Roof Download PDF EPUB FB2

Interacts with outer membrane receptor proteins that carry out high-affinity binding and energy dependent uptake into the periplasmic space of specific substrates such as cobalamin, and various iron compounds (such as iron dicitrate, enterochelin, aerobactin, etc.). In the absence of TonB these receptors bind their substrates but do not carry out active transport.

at the carboxy terminus of TonB could be a membrane anchor. Tofurther investigate the membrane topology of TonB, weconstructed tonB-phoA genefusions byoligonucleotide-directeddeletionmutagenesis (1, 2).

Toavoidproblemswith potentially toxic TonB-PhoAfusion proteins (1, 3, 21), the expression of the tonB gene was first placed under the Cited by: The ExbD protein is involved in the energy-coupled transport of ferric siderophores, vitamin B12, and B-group colicins across the outer membrane of Escherichia coli.

In order to study ExbD membrane topology, ExbD-beta-lactamase fusion proteins were by:   Analysis of Escherichia coli TonB membrane topology by use of PhoA fusions. S K Roof, J D Allard, K P Bertrand, K Postle Journal of Bacteriology Sep(17) ; DOI: /jbCited by: Abstract The ExbB protein together with the ExbD and TonB proteins is involved in energy-coupled transport across the outer membrane of Escherichia coli.

To understand this unusual process it is required to determine the subcellular location of ExbB and its transmembrane by: Abstract In Gram-negative bacteria like Escherichia coli the ExbB−ExbD−TonB protein complex is anchored to the cytoplasmic membrane and is involved in energization of outer membrane transport.

Outer membrane proteins catalyze energy-coupled transport of scarce nutrients. Export systems in Escherichia coli contain membrane fusion proteins which seem to bring a cytoplasmic membrane transporter (belonging to either the ATP-binding cassette family, the major facilitator family, or the multidrug resistance family) into contact with outer membrane proteins such as TolC (16, 38).

Overexpression of the Escherichia coli TolQ protein leads to a null‐FtsN‐like and identified by protein and topology relative to the cytoplasmic membrane.

This did not appear to result from an arabinose dilution effect as the control pairing of TolQ with TonB, a CM protein with a topology similar to that of FtsN still. The TolQ and TolR proteins of Escherichia coli are required for the uptake of group A colicins and for infection by filamentous phages.

Their topology in the cytoplasmic membrane was determined by cleavage with aminopeptidase K, proteinase K, and trypsin in spheroplasts and cell lysates. Contains an N-terminal domain that anchors the protein to the inner membrane, a central domain (domain II), and a C-terminal domain (domain III), which is the functional portion of the protein (PubMed).

The C-terminal domain is involved in interaction with TolB and Pal, and is also involved in direct interaction with colicins and phages.

To cross the outer membrane of Gram-negative bacteria such as Escherichia coli, large, scarce, and important nutrients such as iron or vitamin B12 first bind to specific outer membrane transporters.

A complex of the cytoplasmic membrane proteins ExbB, ExbD, and TonB transduces energy derived from the cytoplasmic membrane. However, outer membrane proteins together with the Tol-Pal and TonB systems have been exploited for the entry of macromolecules such as bacteriocins and phage DNA through the Escherichia coli cell envelope.

The TonB system is involved in the Membrane topology of Escherichia coli TonB protein book transport of iron siderophores and vitamin B12, while no more precise physiological role of the. Evidence is presented for a tonB-dependent illicit transport of the compounds across the outer membrane of E.

coli K, the process involving jointly and specifically the Fiu and Cir iron-regulated outer membrane proteins. The protein complement of cellular membranes is notoriously resistant to standard proteomic analysis and structural studies.

As a result, membrane proteomes remain ill-defined. Here, we report a global topology analysis of the Escherichia coli inner membrane proteome. Using C-terminal tagging with the alkaline phosphatase and green fluorescent protein, we established the periplasmic.

The cytoplasmic membrane protein TonB spans the periplasm of the Gram-negative bacterial cell envelope, contacts cognate outer membrane receptors, and facilitates siderophore transport.

The outer. The Tol proteins of Escherichia coli are involved in outer membrane stability. They are also required for the uptake of the group A colicins and the translocation of filamentous phage DNA into the cytoplasm.

The tol-pal genes constitute two operons in the E. coli genome, orf1tolQRA and tolBpalorf2. ABSTRACT TolQ, TolR, and TolA inner membrane proteins of Escherichia coli are involved in maintaining the stability of the outer membrane. They share homology with the ExbB, ExbD, and TonB proteins, respectively.

The Tol-Pal proteins of Escherichia coli are involved in maintaining outer membrane integrity. They form two complexes in the cell envelope. Transmembrane domains of TolQ, TolR, and TolA interact in the cytoplasmic membrane, while TolB and Pal form a complex near the outer membrane.

The N-terminal transmembrane domain of TolA anchors the protein to the cytoplasmic membrane and interacts with. Involved in the uptake of iron in complex with ferrichrome, a hydroxamate-type siderophore. Binds and transports ferrichrome-iron across the outer membrane (PubMed, PubMed).

In addition to its role in ferrichrome-iron transport, transports the antibiotic albomycin, which is a structural analog of ferrichrome, and acts as a receptor for colicin M, microcin J25 and. For membrane protein annotation categories, we had an overall 56% coverage ( out of the total 1, membrane proteins annotated in the STEPdb database for E.

coli) with several categories reaching 70% coverage, whereas nonmembrane protein categories did not exceed 25% coverage (Fig. 1C). Undetected membrane proteins may be due to lack of. "Point mutations in a conserved region (TonB box) of Escherichia coli outer membrane protein BtuB affect vitamin B12 transport." J Bacteriol (12); PMID: Gunter Gunter K, Braun V ().

"In vivo evidence for FhuA outer membrane receptor interaction with the TonB inner membrane protein of Escherichia coli." FEBS Lett (1.

Energy-coupled transport across the outer membrane of Escherichia coli: ExbB binds ExbD and TonB in vitro, and leucine in the periplasmic region and aspartate 25 in the transmembrane region are important for ExbD activity.

Bacteriol. – Escherichia coli TonB protein is exported from the cytoplasm without proteolytic cleavage of its amino terminus. Membrane topology of the Escherichia coli ExbD protein.

In vivo evidence for FhuA outer membrane receptor interaction with the TonB inner membrane protein of Escherichia coli. The ExbB protein together with the ExbD and TonB proteins is involved in energy-coupled transport across the outer membrane of Escherichia coli.

To understand this unusual process it is required to determine the subcellular location of ExbB and its transmembrane arrangement. Despite decades of research, the stoichiometry, subunit organization, and mechanism of action of the membrane proteins of the Ton system remain unclear. We copurified ExbB with ExbD as an ∼ kDa protein-detergent complex, measured by light scattering and by native gels.

Quantitative Coomassie staining revealed a stoichiometry of ExbB4 -ExbD 2. The activity of the FhuA receptor in the outer membrane of Escherichia coli is dependent on the TonB, ExbB and ExbD proteins which are anchored to the cytoplasmic membrane.

Only infection by phage T5 occurs independently of TonB, ExbB and ExbD. In this paper we describe mutated FhuA proteins which displayed either an increased or decreased FhuA activity to phage T5. Escherichia coli (strain K12). Gene Name(s) tonB (synonyms: exbA) Protein Name(s) Protein TonB External Links: UniProt P EMBL K U U U U U U U U U U U U U AP PIR G RefSeq NP_ WP_ PDB 1IHR 1QXX 1U07 1XX3 2GRX 2GSK: PDBsum 1IHR 1QXX.

Colicins are bacterial protein toxins, which are active against Escherichia coli and other related species. They use different ways to kill susceptible cells, ranging from the ability to depolarize the cytoplasmic membrane, to cytotoxic activity against cytoplasmic nucleic acids, or interference with cytoplasmic membrane transporters like bactoprenyl phosphate 〚1〛, 〚2〛, 〚3〛, 〚4.

Here we characterize the inner membrane protein PbgA and report that its depletion attenuates the virulence of Escherichia coli by reducing levels of LPS and outer membrane integrity. J BacterialMuller MM, Vianney A, Lazzaroni JC, Webster RE and Portalier B () Membrane topology of the Escherichia coli ToIR protein required for cell envelope integrity.

J BacterialNagel de Zwaig R and Luria SE () Genetics and physiol ogy of colicin-tolerant mutants of Escherichia coli. Bell PE, Nau CD, Brown JT, Konisky J, Kadner RJ () Genetic suppression demonstrates interaction of TonB protein with outer membrane transport proteins in Escherichia coli.

The important process of nutrient uptake in Escherichia coli, in many cases, involves transit of the nutrient through a class of beta-barrel proteins in the outer membrane known as TonB-dependent. The nucleotide sequence of a cloned section of the Escherichia coli chromosome containing the tonB gene has been determined.

Transcription initiation and termination sites for tonB RNA have been determined by S1 nuclease mapping. The tonB promoter and terminator resemble other E. coli promoters and terminators; the sequence of the tonB terminator region suggests that it may function.

Interacts with outer membrane receptor proteins that carry out high-affinity binding and energy dependent uptake into the periplasmic space of specific substrates.

It could act to transduce energy from the cytoplasmic membrane to specific energy-requiring processes in the outer membrane, resulting in the release into the periplasm of ligands bound by these outer membrane proteins.

ligands at the outer membrane (OM) through TonB-gated transporters. In Escherichia coli, CM proteins TonB, ExbB, and ExbD form a complex which links pmf energy to transport of important nutrients vitamin B12 and iron-siderophore complexes into the cell.

TonB and ExbD have a similar topology with a short N-terminal cytoplasmic. The cell envelope of Escherichia coli is an essential structure that modulates exchanges between the cell and the extra-cellular milieu. Previous proteomic analyses have suggested that it contains a significant number of proteins with no annotated function.

To gain insight into these proteins and the general organization of the cell envelope proteome, we have carried out a systematic analysis. Formation of a gated channel by a ligand-specific transport protein in the bacterial outer membrane. Science. Oct 16; ()– Schöffler H, Braun V.

Transport across the outer membrane of Escherichia coli K12 via the FhuA receptor is regulated by the TonB protein of the cytoplasmic membrane. Mol Gen Genet.

Escherichia coli cells are surrounded by a complex cell wall composed of two concentric lipid bilayers, the outer membrane and the cytoplasmic membrane with a periplasmic space in between. This cell wall plays many functional roles in protection, transport, locomotion, sensing, detoxification, and energy production.

TolQ, TolR, and TolA inner membrane proteins of Escherichia coli are involved in maintaining the stability of the outer membrane. They share homology with the ExbB, ExbD, and TonB proteins. Schöffler H, Braun V.

Transport across the outer membrane of Escherichia coli K12 via the FhuA receptor is regulated by the TonB protein of the cytoplasmic membrane. Mol. Gen. Genet. (2–3): Crossref, Medline, Google Scholar. Structural Biochemistry/Membrane Proteins/Topology. From Wikibooks, open books for an open world Introduction.

It has been well established that membrane proteins must be inserted in a specific topology, an orientation in the lipid bilayer, in order to properly function. a small homodimeric multidrug transporter from Escherichia coli.In Escherichia coli K12, the TonB system serves to couple the electrochemical gradient of the cytoplasmic membrane, protonmotive force (pmf), to high affinity TonB-gated outer membrane transporters, promoting active transport of iron-siderophore complexes and vitamin B 12 across the outer membrane.

Iron is essential for E.Purchase Transport Processes in Eukaryotic and Prokaryotic Organisms, Volume 2 - 1st Edition. Print Book & E-Book. ISBN