TorC apocytochrome negatively autoregulates the trimethylamine N-oxide (TMAO) reductase operon in Escherichia coli

1999 ◽  
Vol 33 (2) ◽  
pp. 284-295 ◽  
Author(s):  
Mireille Ansaldi ◽  
Christophe Bordi ◽  
Michele Lepelletier ◽  
Vincent Mejean
Keyword(s):  
Escherichia Coli ◽  
Tmao Reductase

scholarly journals Enzymatic and physiological properties of the tungsten-substituted molybdenum TMAO reductase from Escherichia coli

1999 ◽  
Vol 32 (1) ◽  
pp. 159-168 ◽  
Author(s):  
Jean Buc ◽  
Claire-Lise Santini ◽  
Roger Giordani ◽  
Mirjam Czjzek ◽  
Long-Fei Wu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Physiological Properties ◽  
Tmao Reductase

Functional and structural analysis of members of the TorD family, a large chaperone family dedicated to molybdoproteins

Microbiology ◽  
2004 ◽  
Vol 150 (4) ◽  
pp. 935-943 ◽  
Author(s):  
Marianne Ilbert ◽  
Vincent Méjean ◽  
Chantal Iobbi-Nivol
Keyword(s):  
Escherichia Coli ◽  
Structural Analysis ◽  
Family Member ◽  
Signal Sequence ◽  
Large Family ◽  
Inhibitory Effect ◽  
Cytoplasmic Protein ◽  
Dmso Reductase ◽  
Tmao Reductase ◽  
Positive Effect

The trimethylamine N-oxide (TMAO) reductase TorA, a DMSO reductase family member, is a periplasmic molybdoenzyme of Escherichia coli. The cytoplasmic protein TorD acts as a chaperone for TorA, allowing the efficient insertion of the molybdenum cofactor into the apoform of the enzyme prior to its secretion. This paper demonstrates that TorD is a member of a large family of prokaryotic proteins that are structurally related. Moreover, their genes generally belong to operons also encoding molybdoenzymes of the DMSO reductase family. Both the TorD and the DMSO reductase families present a similar phylogenetic organization, suggesting a co-evolution of these two families of proteins. This hypothesis is also supported by the fact that the TorD and DmsD chaperones cannot replace each other and thus appear dedicated to specific molybdopartners. Interestingly, it was found that the positive effect of TorD on TorA maturation, and the partial inhibitory effect of DmsD and homologues, are independent of the TorA signal sequence.

scholarly journals Reconstitution of the Trimethylamine Oxide Reductase Regulatory Elements of Shewanella oneidensis in Escherichia coli

2002 ◽  
Vol 184 (5) ◽  
pp. 1262-1269 ◽  
Author(s):  
Stéphanie Gon ◽  
Jean-Claude Patte ◽  
Jean-Philippe Dos Santos ◽  
Vincent Méjean
Keyword(s):  
Escherichia Coli ◽  
Gene Cluster ◽  
Response Regulator ◽  
Regulatory Gene ◽  
Regulatory System ◽  
Regulatory Elements ◽  
Oxygen Control ◽  
E Coli ◽  
Trimethylamine Oxide ◽  
Tmao Reductase

ABSTRACT Several bacteria can grow by using small organic compounds such as trimethylamine oxide (TMAO) as electron acceptors. In Shewanella species, the TMAO reductase respiratory system is encoded by the torECAD operon. We showed that production of the TMAO reductase of S. oneidensis was induced by TMAO and repressed by oxygen, and we noticed that a three-gene cluster (torSTR) encoding a complex two-component regulatory system was present downstream of the torECAD operon. We introduced the torSTR gene cluster into Escherichia coli and showed that this regulatory gene cluster is involved in TMAO induction of the torE promoter but plays no role in the oxygen control. The TorR response regulator was purified, and gel shift and footprinting experiments revealed that TorR binds to a single region located about 70 bases upstream of the transcription start site of the tor structural operon. By deletion analysis, we confirmed that the TorR operator site is required for induction of the tor structural promoter. As the TMAO regulatory system of S. oneidensis is homologous to that of E. coli, we investigated a possible complementation between the TMAO regulatory components of the two bacteria. Interestingly, TorSec, the TMAO sensor of E. coli, was able to transphosphorylate TorRso, the TMAO response regulator of S. oneidensis.

scholarly journals The torYZ (yecK bisZ) Operon Encodes a Third Respiratory Trimethylamine N-Oxide Reductase inEscherichia coli

2000 ◽  
Vol 182 (20) ◽  
pp. 5779-5786 ◽  
Author(s):  
Stéphanie Gon ◽  
Jean-Claude Patte ◽  
Vincent Méjean ◽  
Chantal Iobbi-Nivol
Keyword(s):  
Escherichia Coli ◽  
Dimethyl Sulfoxide ◽  
Gene Product ◽  
Respiratory System ◽  
Common Ancestor ◽  
Catalytic Properties ◽  
Inescherichia Coli ◽  
Low Levels ◽  
A Minor ◽  
Tmao Reductase

ABSTRACT The bisZ gene of Escherichia coli was previously described as encoding a minor biotin sulfoxide (BSO) reductase in addition to the main cytoplasmic BSO reductase, BisC. In this study, bisZ has been renamed torZ based on the findings that (i) the torZ gene product, TorZ, is able to reduce trimethylamine N-oxide (TMAO) more efficiently than BSO; (ii) although TorZ is more homologous to BisC than to the TMAO reductase TorA (63 and 42% identity, respectively), it is located mainly in the periplasm as is TorA; (iii)torZ belongs to the torYZ operon, and the first gene, torY (formerly yecK), encodes a pentahemic c-type cytochrome homologous to the TorC cytochrome of the TorCAD respiratory system. Furthermore, the torYZ operon encodes a third TMAO respiratory system, with catalytic properties that are clearly different from those of the TorCAD and the DmsABC systems. ThetorYZ and the torCAD operons may have diverged from a common ancestor, but, surprisingly, notorD homologue is found in the sequences aroundtorYZ. Moreover, the torYZ operon is expressed at very low levels under the conditions tested, and, in contrast to torCAD, it is not induced by TMAO or dimethyl sulfoxide.

Regulation of the trimethylamine N-oxide (TMAO) reductase in Escherichia coli: Analysis of tor::Mud1 operon fusion

1984 ◽  
Vol 195 (1-2) ◽  
pp. 351-355 ◽  
Author(s):  
Marie-Claire Pascal ◽  
Jean-François Burini ◽  
Marc Chippaux
Keyword(s):  
Escherichia Coli ◽  
Tmao Reductase

Structural organization of escherichia coli ribosomes as determined by immuno electron microscopy

1978 ◽  
Vol 36 (2) ◽  
pp. 166-167 ◽  
Author(s):  
G. Stöffler ◽  
R.W. Bald ◽  
J. Dieckhoff ◽  
H. Eckhard ◽  
R. Lührmann ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Ribosomal Proteins ◽  
Structural Organization ◽  
Three Dimensional ◽  
Ribosomal Subunit ◽  
Spatial Arrangement ◽  
Small Subunit ◽  
Antibody Binding ◽  
Immuno Electron Microscopy

A central step towards an understanding of the structure and function of the Escherichia coli ribosome, a large multicomponent assembly, is the elucidation of the spatial arrangement of its 54 proteins and its three rRNA molecules. The structural organization of ribosomal components has been investigated by a number of experimental approaches. Specific antibodies directed against each of the 54 ribosomal proteins of Escherichia coli have been performed to examine antibody-subunit complexes by electron microscopy. The position of the bound antibody, specific for a particular protein, can be determined; it indicates the location of the corresponding protein on the ribosomal surface.The three-dimensional distribution of each of the 21 small subunit proteins on the ribosomal surface has been determined by immuno electron microscopy: the 21 proteins have been found exposed with altogether 43 antibody binding sites. Each one of 12 proteins showed antibody binding at remote positions on the subunit surface, indicating highly extended conformations of the proteins concerned within the 30S ribosomal subunit; the remaining proteins are, however, not necessarily globular in shape (Fig. 1).

Sites of Adsorption of the Bacteriophages T3 and T5 on the Wall of Escherichia Coli B.

1967 ◽  
Vol 25 ◽  
pp. 96-97
Author(s):  
Manfred E. Bayer
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Electron Microscope ◽  
Uranyl Acetate ◽  
E Coli ◽  
Receptor Sites ◽  
Rigid Cell Wall ◽  
Host Cell Surface ◽  
Bacterial Viruses ◽  
Escherichia Coli B

Bacterial viruses adsorb specifically to receptors on the host cell surface. Although the chemical composition of some of the cell wall receptors for bacteriophages of the T-series has been described and the number of receptor sites has been estimated to be 150 to 300 per E. coli cell, the localization of the sites on the bacterial wall has been unknown.When logarithmically growing cells of E. coli are transferred into a medium containing 20% sucrose, the cells plasmolize: the protoplast shrinks and becomes separated from the somewhat rigid cell wall. When these cells are fixed in 8% Formaldehyde, post-fixed in OsO4/uranyl acetate, embedded in Vestopal W, then cut in an ultramicrotome and observed with the electron microscope, the separation of protoplast and wall becomes clearly visible, (Fig. 1, 2). At a number of locations however, the protoplasmic membrane adheres to the wall even under the considerable pull of the shrinking protoplast. Thus numerous connecting bridges are maintained between protoplast and cell wall. Estimations of the total number of such wall/membrane associations yield a number of about 300 per cell.

Infection of Escherichia coli with bacteriophages

1969 ◽  
Vol 27 ◽  
pp. 370-371
Author(s):  
Manfred E. Bayer
Keyword(s):  
Escherichia Coli ◽  
Nucleic Acid ◽  
Cell Surface ◽  
Virus Type ◽  
Infection Process ◽  
Adsorption Site ◽  
The Other ◽  
Specific Receptors ◽  
Bacterial Receptors

The first step in the infection of a bacterium by a virus consists of a collision between cell and bacteriophage. The presence of virus-specific receptors on the cell surface will trigger a number of events leading eventually to release of the phage nucleic acid. The execution of the various "steps" in the infection process varies from one virus-type to the other, depending on the anatomy of the virus. Small viruses like ØX 174 and MS2 adsorb directly with their capsid to the bacterial receptors, while other phages possess attachment organelles of varying complexity. In bacteriophages T3 (Fig. 1) and T7 the small conical processes of their heads point toward the adsorption site; a welldefined baseplate is attached to the head of P22; heads without baseplates are not infective.

The Nature of the Intramembrane Particle

1980 ◽  
Vol 38 ◽  
pp. 688-691
Author(s):  
A.J. Verkleij
Keyword(s):  
Escherichia Coli ◽  
Tight Junction ◽  
Gap Junction ◽  
The Other ◽  
Fracture Face ◽  
Band 3 Protein ◽  
Satisfactory Explanation ◽  
Freeze Fracturing ◽  
Intramembrane Particle ◽  
Luminal Membrane

Freeze-fracturing splits membranes into two helves, thus allowing an examination of the membrane interior. The 5-10 rm particles visible on both monolayers are widely assumed to be proteinaceous in nature. Most membranes do not reveal impressions complementary to particles on the opposite fracture face, if the membranes are fractured under conditions without etching. Even if it is considered that shadowing, contamination or fracturing itself might obscure complementary pits', there is no satisfactory explanation why under similar physical circimstances matching halves of other membranes can be visualized. A prominent example of uncomplementarity is found in the erythrocyte manbrane. It is wall established that band 3 protein and possibly glycophorin represents these nonccmplanentary particles. On the other hand a number of membrane types show pits opposite the particles. Scme well known examples are the ";gap junction',"; tight junction, the luminal membrane of the bladder epithelial cells and the outer membrane of Escherichia coli.

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