Identification and analysis of three virulence-associated TonB-dependent outer membrane receptors of Pseudomonas fluorescens

2014 ◽  
Vol 110 (3) ◽  
pp. 181-191 ◽  
Author(s):  
Sr Zhang ◽  
L Zhang ◽  
L Sun
Keyword(s):  
Pseudomonas Fluorescens ◽  
Outer Membrane ◽  
Membrane Receptors

scholarly journals Stereospecific recognition of pyochelin and enantio-pyochelin by the PchR proteins in fluorescent pseudomonads

Microbiology ◽  
2010 ◽  
Vol 156 (6) ◽  
pp. 1772-1782 ◽  
Author(s):  
Zeb A. Youard ◽  
Cornelia Reimmann
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Transcriptional Regulation ◽  
Pseudomonas Fluorescens ◽  
Outer Membrane ◽  
Growth Promotion ◽  
Membrane Receptors ◽  
Iron Limitation ◽  
Fluorescent Pseudomonads ◽  
Terminal Domain ◽  
Native Ligand

The siderophore pyochelin of Pseudomonas aeruginosa promotes growth under iron limitation and induces the expression of its biosynthesis genes via the transcriptional AraC/XylS-type regulator PchR. Pseudomonas fluorescens strain CHA0 makes the optical antipode of pyochelin termed enantio-pyochelin, which also promotes growth and induces the expression of its biosynthesis genes when iron is scarce. Growth promotion and signalling by pyochelin and enantio-pyochelin are highly stereospecific and are known to involve the pyochelin and enantio-pyochelin outer-membrane receptors FptA and FetA, respectively. Here we show that stereospecificity in signalling is also based on the stereospecificity of the homologous PchR proteins of P. aeruginosa and P. fluorescens towards their respective siderophore effectors. We found that PchR functioned in the heterologous species only if supplied with its native ligand and that the FptA and FetA receptors enhanced the efficiency of signalling. By constructing and expressing hybrid and truncated PchR regulators we showed that the weakly conserved N-terminal domain of PchR is responsible for siderophore specificity. Thus, both uptake and transcriptional regulation confer stereospecificity to pyochelin and enantio-pyochelin biosynthesis.

TonB or not TonB: is that the question?This paper is one of a selection of papers published in a Special Issue entitled CSBMCB 53rd Annual Meeting — Membrane Proteins in Health and Disease, and has undergone the Journal’s usual peer review process.

2011 ◽  
Vol 89 (2) ◽  
pp. 87-97 ◽  
Author(s):  
Karla D. Krewulak ◽  
Hans J. Vogel
Keyword(s):  
Outer Membrane ◽  
Metal Ion ◽  
Peer Review Process ◽  
Three Dimensional ◽  
Membrane Receptor ◽  
Membrane Receptors ◽  
Dimensional Structure ◽  
Outer Membrane Receptor ◽  
Different Strains ◽  
Low Molecular Weight Iron

Bacteria are able to survive in low-iron environments by sequestering this metal ion from iron-containing proteins and other biomolecules such as transferrin, lactoferrin, heme, hemoglobin, or other heme-containing proteins. In addition, many bacteria secrete specific low molecular weight iron chelators termed siderophores. These iron sources are transported into the Gram-negative bacterial cell through an outer membrane receptor, a periplasmic binding protein (PBP), and an inner membrane ATP-binding cassette (ABC) transporter. In different strains the outer membrane receptors can bind and transport ferric siderophores, heme, or Fe3+ as well as vitamin B12, nickel complexes, and carbohydrates. The energy that is required for the active transport of these substrates through the outer membrane receptor is provided by the TonB/ExbB/ExbD complex, which is located in the cytoplasmic membrane. In this minireview, we will briefly examine the three-dimensional structure of TonB and the current models for the mechanism of TonB-dependent energy transduction. Additionally, the role of TonB in colicin transport will be discussed.

scholarly journals Iron-Utilization System in Vibrio vulnificus M2799

Marine Drugs ◽  
2021 ◽  
Vol 19 (12) ◽  
pp. 710
Author(s):  
Katsushiro Miyamoto ◽  
Hiroaki Kawano ◽  
Naoko Okai ◽  
Takeshi Hiromoto ◽  
Nao Miyano ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Vibrio Vulnificus ◽  
Binding Protein ◽  
Membrane Receptors ◽  
Outer Membrane Receptor ◽  
Ferric Ions ◽  
Periplasmic Binding Protein ◽  
Serious Infections ◽  
Periplasmic Binding Proteins ◽  
Export System

Vibrio vulnificus is a Gram-negative pathogenic bacterium that causes serious infections in humans and requires iron for growth. A clinical isolate, V. vulnificus M2799, secretes a catecholate siderophore, vulnibactin, that captures ferric ions from the environment. In the ferric-utilization system in V. vulnificus M2799, an isochorismate synthase (ICS) and an outer membrane receptor, VuuA, are required under low-iron conditions, but alternative proteins FatB and VuuB can function as a periplasmic-binding protein and a ferric-chelate reductase, respectively. The vulnibactin-export system is assembled from TolCV1 and several RND proteins, including VV1_1681. In heme acquisition, HupA and HvtA serve as specific outer membrane receptors and HupB is a sole periplasmic-binding protein, unlike FatB in the ferric-vulnibactin utilization system. We propose that ferric-siderophore periplasmic-binding proteins and ferric-chelate reductases are potential targets for drug discovery in infectious diseases.

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