The TolC protein of Escherichia coli serves as a cell-surface receptor for the newly characterized TLS bacteriophage 1 1Edited by B. Holland

German, Greg; Misra, Rajeev

doi:10.1006/jmbi.2001.4578

Cited by 98 publications

(106 citation statements)

References 32 publications

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“…In their discussion of the phage T1 genome, Roberts et al (75) mentioned that the genome of a very close relative of phage T1, phage TLS (38), has been completely sequenced by Gregory German and Rajeev Misra at the University of Arizona, but this genome sequence has not been deposited in a public database. There are clear differences that distinguish phages Rtp and TLS from each other.…”

Section: Resultsmentioning

confidence: 99%

The Genome of the Novel Phage Rtp, with a Rosette-Like Tail Tip, IsHomologous to the Genome of Phage T1

et al. 2006

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A new Escherichia coli phage, named Rtp, was isolated and shown to be closely related to phage T1. Electron microscopy revealed that phage Rtp has a morphologically unique tail tip consisting of four leaf-like structures arranged in a rosette, whereas phage T1 has thinner, flexible leaves that thicken toward the ends. In contrast to T1, Rtp did not require FhuA and TonB for infection. The 46.2-kb genome of phage Rtp encodes 75 open reading frames, 47 of which are homologous to phage T1 genes. Like phage T1, phage Rtp encodes a large number of small genes at the genome termini that exhibit no sequence similarity to known genes. Six predicted genes larger than 300 nucleotides in the highly homologous region of Rtp are not found in T1. Two predicted HNH endonucleases are encoded at positions different from those in phage T1. The sequence similarity of rtp37, -38, -39, -41, -42, and -43 to equally arranged genes of lambdoid phages suggests a common tail assembly initiation complex. Protein Rtp43 is homologous to the J protein, which determines host specificity. Since the two proteins differ most in the C-proximal area, where the binding site to the LamB receptor resides in the J protein, we propose that Rtp43 contributes to Rtp host specificity. Lipoproteins similar to the predicted lipoprotein Rtp45 are found in a number of phages (encoded by cor genes) in which they prevent superinfection by inactivating the receptors. We propose that, similar to the proposed function of the phage T5 lipoprotein, Rtp45 prevents inactivation of Rtp by adsorption to its receptor during cells lysis. Rtp52 is a putative transcriptional regulator, for which 10 conserved inverted repeats were identified upstream of genes in the Rtp genome. In contrast, the much larger E. coli genome has only one such repeat sequence.Phages form the largest group of "organisms" on earth and display a huge genetic diversity. To date, 228 phage genomes have been sequenced and the 252 sequenced bacterial genomes contain many prophages and phage-like elements. Horizontal gene transfer between phages and their hosts largely contributes to the genetic variety of the phages and their hosts. During evolution, phages endowed bacteria with new functions enabling them to occupy new environmental niches. Phage genomics provides data for tracing phage and bacterial evolution. It is therefore desirable to determine the sequences of as many phages as possible.Escherichia coli and a selected group of E. coli phages paved the way into molecular biology. Among the phages was T1 (1, 29), whose genome sequence was, however, not determined until 2004, over 60 years after its discovery (75). The phage T1 genome encodes 77 open reading frames (ORFs), 37 of which are homologous to described phage ORFs. Functions have been assigned to 27 ORFs. The largest functional group consists of tail proteins. Twenty-two ORFs encoding putative proteins of fewer than 100 amino acid (aa) residues lie predominantly close to the termini. These putative proteins display no sequence similarity to...

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Section: Resultsmentioning

confidence: 99%

The Genome of the Novel Phage Rtp, with a Rosette-Like Tail Tip, IsHomologous to the Genome of Phage T1

et al. 2006

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“…Phage specificity of infection is determined by the interaction between receptors present on the host cell outer membrane and phage host recognition proteins [9].…”

Section: Introductionmentioning

confidence: 99%

“…It was suggested that virus loss during this treatment is due to association with wastewater particulates, which subsequently settle and become components of sludge [10]. Other evidence indicates that mixed liquor suspended solids (MLSS) of activated sludge inactivate and remove virucidal agents [9]. Most studies on bacteriophages in wastewater treatment plants are based on the characterization of pure phages seeded to the plant or model environments.…”

Section: Introductionmentioning

confidence: 99%

Seasonal change and fate of coliphages infected to Escherichia coli O157:H7 in a wastewater treatment plant

et al. 2003

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Seasonal change of virulent phage infected to two E. coli O157:H7 strains (O:157-phage) in the influent of a domestic wastewater treatment plant in the central part of Japan and fate of O:157-phage in the plant were monitored almost monthly from March 2001 to February 2002. Coliphage infected to nonpathogenic E. coli O157:H7 ATCC43888 (43888-phage) was detected for 1 year. On the other hand, phage infected to pathogenic E. coli O157:H7 EDL933 (EDL-phage) was detected intermittently. Concentration of EDL-phage was almost one-tenth of that of 43888-phage. The progressive decrease in phage concentration with the treatment steps was observed. No phage was detected in the supernatant from the secondary settling tank and effluent. PCR amplification of the Stx 2 gene that encodes Shiga toxin (Stx) was observed when O:157-phage concentration in the influent was high Â 10 3 PFU/ml order. Concentration and percentage of suspended O:157-phage decreased with the progress of the wastewater treatment. 933W phage, which encodes Stx 2 gene, was more fragile and sensitive to chlorination than T4 phage. However, addition of 0.02 mg/l chlorine, in conformance with the required concentration of the plant, did not affect the viability of T4 and 933W phages. On the other hand, 1 mg/l chlorine inactivated the 933W phage significantly. r

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“…These studies include the isolation of tolC missense mutations affecting ␣-hemolysin secretion (35) and TolC's cell surface interactions with bacteriophage TLS and colicin E1 (13). Recently, two systematic studies conducted by V. Koronakis's group determined the mechanism of aperture opening during substrate translocation (1,9).…”

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Antibiotic-Sensitive TolC Mutants and Their Suppressors

Augustus¹,

Celaya

Husain

et al. 2004

J Bacteriol

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The TolC protein of Escherichia coli, through its interaction with AcrA and AcrB, is thought to form a continuous protein channel that expels inhibitors from the cell. Consequently, tolC null mutations display a hypersensitive phenotype. Here we report the isolation and characterization of tolC missense mutations that direct the synthesis of mutant TolC proteins partially disabled in their efflux role. All alterations, consisting of single amino acid substitutions, were localized within the periplasmic ␣-helical domain. In two mutants carrying an I106N or S350F substitution, the hypersensitivity phenotype may be in part due to aberrant TolC assembly. However, two other alterations, R367H and R390C, disrupted efflux function by affecting interactions among the helices surrounding TolC's periplasmic tunnel. Curiously, these two TolC mutants were sensitive to a large antibiotic, vancomycin, and exhibited a Dex ؉ phenotype. These novel phenotypes of TolC R367H and TolC R390C were likely the result of a general influx of molecules through a constitutively open tunnel aperture, which normally widens only when TolC interacts with other proteins during substrate translocation. An intragenic suppressor alteration (T140A) was isolated from antibiotic-resistant revertants of the hypersensitive TolC R367H mutant. T140A also reversed, either fully (R390C) or partially (I106N and S350F), the hypersensitivity phenotype of other TolC mutants. Our data suggest that this global suppressor phenotype of T140A is the result of impeded antibiotic influx caused by tapering of the tunnel passage rather than by correcting individual mutational defects. Two extragenic suppressors of TolC R367H , mapping in the regulatory region of acrAB, uncoupled the AcrR-mediated repression of the acrAB genes. The resulting overexpression of AcrAB reduced the hypersensitivity phenotype of all the TolC mutants. Similar results were obtained when the chromosomal acrR gene was deleted or the acrAB genes were expressed from a plasmid. Unlike the case for the intragenic suppressor T140A, the overexpression of AcrAB diminished hypersensitivity towards only erythromycin and novobiocin, which are substrates of the TolC-AcrAB efflux pump, but not towards vancomycin, which is not a substrate of this pump. This showed that the two types of suppressors produced their effects by fundamentally different means, as the intragenic suppressor decreased the general influx while extragenic suppressors increased the efflux of TolC-AcrAB pump-specific antibiotics.Escherichia coli cells lacking the outer membrane protein (OMP) TolC display hypersensitivity to a variety of inhibitors, including bile salts, detergents, and hydrophobic antibiotics (38). This was initially thought to be due to a defect in the outer membrane permeability barrier as a result of a defective lipopolysaccharide (LPS) (32). However, it was shown that tolC and rfa (LPS core) mutations produce an additive effect on hypersensitivity, thus suggesting that tolC mutations may confer hypersensitivity indepen...

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The TolC protein of Escherichia coli serves as a cell-surface receptor for the newly characterized TLS bacteriophage 1 1Edited by B. Holland

Cited by 98 publications

References 32 publications

The Genome of the Novel Phage Rtp, with a Rosette-Like Tail Tip, IsHomologous to the Genome of Phage T1

The Genome of the Novel Phage Rtp, with a Rosette-Like Tail Tip, IsHomologous to the Genome of Phage T1

Seasonal change and fate of coliphages infected to Escherichia coli O157:H7 in a wastewater treatment plant

Antibiotic-Sensitive TolC Mutants and Their Suppressors

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