Idioma:

Molecular mechanism of ferricsiderophore passage through the outer membrane receptor proteins of Escherichia coli

Chakraborty, Ranjan ; Storey, Erin ; van der Helm, Dick

Biometals, 2007-06, Vol.20 (3-4), p.263-274 [Periódico revisado por pares]

Netherlands: New York : Kluwer Academic Publishers-Plenum Publishers

Texto completo disponível

Citações Citado por

Enviar para

Título:
Molecular mechanism of ferricsiderophore passage through the outer membrane receptor proteins of Escherichia coli
Autor: Chakraborty, Ranjan ; Storey, Erin ; van der Helm, Dick
Assuntos: Bacterial Outer Membrane Proteins - chemistry ; Bacterial Outer Membrane Proteins - genetics ; Bacterial Outer Membrane Proteins - metabolism ; Biological Transport ; Carrier Proteins - chemistry ; Carrier Proteins - genetics ; Carrier Proteins - metabolism ; Cysteine - metabolism ; E coli ; Escherichia coli ; Escherichia coli - metabolism ; Escherichia coli Proteins - chemistry ; Escherichia coli Proteins - genetics ; Escherichia coli Proteins - metabolism ; ferrichrome ; FhuA ; Iron ; Iron - chemistry ; Iron - metabolism ; Membranes ; Molecular biology ; Molecular Structure ; Mutagenesis, Site-Directed ; Protein Binding ; Protein Conformation ; Proteins ; Pseudomonas aeruginosa ; Receptors, Cell Surface - chemistry ; Receptors, Cell Surface - genetics ; Receptors, Cell Surface - metabolism ; Siderophore ; Siderophores - chemistry ; Siderophores - genetics ; Siderophores - metabolism
É parte de: Biometals, 2007-06, Vol.20 (3-4), p.263-274
Notas: http://dx.doi.org/10.1007/s10534-006-9060-9
ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
content type line 23
ObjectType-Article-2
ObjectType-Feature-1
Descrição: Iron is an essential nutrient for all microorganisms with a few exceptions. Microorganisms use a variety of systems to acquire iron from the surrounding environment. One such system includes production of an organic molecule known as a siderophore by many bacteria and fungi. Siderophores have the capacity to specifically chelate ferric ions. The ferricsiderophore complex is then transported into the cell via a specific receptor protein located in the outer membrane. This is an energy dependent process and is the subject of investigation in many research laboratories. The crystal structures of three outer membrane ferricsiderophore receptor proteins FepA, FhuA and FecA from Escherichia coli and two FpvA and FptA from Pseudomonas aeruginosa have recently been solved. Four of them, FhuA, FecA, FpvA and FptA have been solved in ligand-bound forms, which gave insight into the residues involved in ligand binding. The structures are similar and show the presence of similar domains; for example, all of them consist of a 22 strand-β-barrel formed by approximately 600 C-terminal residues while approximately 150 N-terminal residues fold inside the barrel to form a plug domain. The plug domain obstructs the passage through the barrel; therefore our research focuses on the mechanism through which the ferricsiderophore complex is transported across the receptor into the periplasm. There are two possibilities, one in which the plug domain is expelled into the periplasm making way for the ferricsiderophore complex and the second in which the plug domain undergoes structural rearrangement to form a channel through which the complex slides into the periplasm. Multiple alignment studies involving protein sequences of a large number of outer membrane receptor proteins that transport ferricsiderophores have identified several conserved residues. All of the conserved residues are located within the plug and barrel domain below the ligand binding site. We have substituted a number of these residues in FepA and FhuA with either alanine or glutamine resulting in substantial changes in the chemical properties of the residues. This was done to study the effect of the substitutions on the transport of ferricsiderophores. Another strategy used was to create a disulfide bond between the residues located on two adjacent β-strands of the plug domain or between the residues of the plug domain and the β-barrel in FhuA by substituting appropriate residues with cysteine. We have looked for the variants where the transport is affected without altering the binding. The data suggest a distinct role of these residues in the mechanism of transport. Our data also indicate that these transporters share a common mechanism of transport and that the plug remains within the barrel and possibly undergoes rearrangement to form a channel to transport the ferricsiderophore from the binding site to the periplasm.
Editor: Netherlands: New York : Kluwer Academic Publishers-Plenum Publishers
Idioma: Inglês;Holandês

Links

View this record in MEDLINE/PubMed

Voltar para lista de resultados

Realização: Logos de Redes Sociais:

Molecular mechanism of ferricsiderophore passage through the outer membrane receptor proteins of Escherichia coli

Chakraborty, Ranjan ; Storey, Erin ; van der Helm, Dick

Netherlands: New York : Kluwer Academic Publishers-Plenum Publishers

Buscando em bases de dados remotas. Favor aguardar.