Cell division, one-carbon metabolism and methionine synthesis in a metK-deficient Escherichia coli mutant, and a role for MmuM

El-Hajj, Ziad W.; Reyes‐Lamothe, Rodrigo; Newman, E. B.

doi:10.1099/mic.0.069682-0

Cited by 9 publications

(11 citation statements)

References 36 publications

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“…In the context of strain MOB1490, the rickettsial AdoMet transporter had previously been shown to have a K T for AdoMet uptake of 4.7 mM (Tucker et al, 2003). Our results with unmodified AdoMet are consistent with those findings, and with earlier studies on the effects of AdoMet levels on E. coli growth (El-Hajj et al, 2013;Posnick & Samson, 1999). In the rich medium the maximal culture density was reached at the maximal rate at AdoMet concentrations ¢4 mM.…”

Section: Assessment Of Adomet Utilizationsupporting

confidence: 83%

“…Luria-Bertani (LB) medium or MOPS-based glucose minimal medium (Teknova) were used for some experiments. MOPS glucose media also contained 0.2 mM L-Met, as AdoMet can repress methionine biosynthetic genes (El-Hajj et al, 2013). [For comparison, LB medium contains~6 mM L-Met (Sezonov et al, 2007).]…”

Section: Methodsmentioning

confidence: 99%

“…In minimal medium there was a clear toxic effect of higher concentrations of AdoMet, reflected in both lower growth rates and reduced maximum culture densities as [AdoMet] increased. This was not due to starvation for methionine; in minimal media, methionine as well as AdoMet must be provided for MOB1490 growth, to overcome AdoMet co-repression of methionine biosynthesis (El-Hajj et al, 2013), and our minimal medium was supplemented with 0.2 mM L-Met. The apparent toxicity was also not due to components from the MetK reactions used to make AdoMet from L-Met and ATP, as we saw the same phenomenon (but to a lesser extent) with purified commercial AdoMet (Fig.…”

Section: Assessment Of Adomet Utilizationmentioning

confidence: 99%

“…The morphology of cells grown in these cultures also provides useful information, as E. coli cells restricted for AdoMet exhibit a division defect that leads to abnormally long cells (El-Hajj et al, 2013;Wang et al, 2005). Culture samples from the end points of each growth curve experiment were spotted onto slides, stained with crystal violet, and examined under a microscope.…”

Section: Effects Of Adomet Analogues On Cell Morphologymentioning

confidence: 99%

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A surprising range of modified-methionyl S-adenosylmethionine analogues support bacterial growth

et al. 2015

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S-Adenosyl-L-methionine (AdoMet) is an essential metabolite, serving in a very wide variety of metabolic reactions. The enzyme that produces AdoMet from L-methionine and ATP (methionine adenosyltransferase, MAT) is thus an attractive target for antimicrobial agents. We previously showed that a variety of methionine analogues are MAT substrates, yielding AdoMet analogues that function in specific methyltransfer reactions. However, this left open the question of whether the modified AdoMet molecules could support bacterial growth, meaning that they functioned in the full range of essential AdoMet-dependent reactions. The answer matters both for insight into the functional flexibility of key metabolic enzymes, and for drug design strategies for both MAT inhibitors and selectively toxic MAT substrates. In this study, methionine analogues were converted in vitro into AdoMet analogues, and tested with an Escherichia coli strain lacking MAT (DmetK) but that produces a heterologous AdoMet transporter. Growth that yields viable, morphologically normal cells provides exceptionally robust evidence that the analogue functions in every essential reaction in which AdoMet participates. Overall, the S-adenosylated derivatives of all tested L-methionine analogues modified at the carboxyl moiety, and some others as well, showed in vivo functionality sufficient to allow good growth in both rich and minimal media, with high viability and morphological normality. As the analogues were chosen based on incompatibility with the reactions via which AdoMet is used to produce acylhomoserine lactones (AHLs) for quorum sensing, these results support the possibility of using this route to selectively interfere with AHL biosynthesis without inhibiting bacterial growth.

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Section: Assessment Of Adomet Utilizationsupporting

confidence: 83%

Section: Methodsmentioning

confidence: 99%

Section: Assessment Of Adomet Utilizationmentioning

confidence: 99%

Section: Effects Of Adomet Analogues On Cell Morphologymentioning

confidence: 99%

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A surprising range of modified-methionyl S-adenosylmethionine analogues support bacterial growth

et al. 2015

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“…This strain was derived from our earlier mutant carrying a deletion in metK, which codes for S-adenosylmethionine (SAM) synthetase; SAM is the major donor of methyl groups (8,9). Our metK deletion mutant, MEW649, had to be exogenously provided with both SAM and methionine in order to grow, as well as with a SAM transporter, since E. coli does not natively express one (10).…”

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confidence: 99%

An Escherichia coli Mutant That Makes Exceptionally Long Cells

El-Hajj

Newman

2015

J Bacteriol

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Although Escherichia coli is a very small (1-to 2-m) rod-shaped cell, here we describe an E. coli mutant that forms enormously long cells in rich media such as Luria broth, as long indeed as 750 m. These extremely elongated (eel) cells are as long as the longest bacteria known and have no internal subdivisions. They are metabolically competent, elongate rapidly, synthesize DNA, and distribute cell contents along this length. They lack only the ability to divide. The concentration of the essential cell division protein FtsZ is reduced in these eel cells, and increasing this concentration restores division. IMPORTANCEEscherichia coli is usually a very small bacterium, 1 to 2 m long. We have isolated a mutant that forms enormously long cells, 700 times longer than the usual E. coli cell. E. coli filaments that form under other conditions usually die within a few hours, whereas our mutant is fully viable even when it reaches such lengths. This mutant provides a useful tool for the study of aspects of E. coli physiology that are difficult to investigate with small cells. We think of bacterial cells as small organisms. Cells in a growing Escherichia coli culture look like rigid rods 0.5 m wide by 2 m long. Each rod elongates to twice its original length by making new peptidoglycan in many disperse areas by using an enzyme complex including penicillin-binding protein 2 (PBP2). The organism then localizes peptidoglycan synthesis to midcell by using a different enzyme complex, based on PBP3. This changes the direction of cell wall synthesis; the cell wall invaginates from both sides, thus forming two identical daughter cells (1, 2, 3).E. coli cells are small because their division controls are set accordingly (4). However, they can be much longer if a shift to PBP3 cannot be made but conditions still permit PBP2 function. This occurs under many circumstances. Mutants with conditional temperature-sensitive mutations in the gene coding for the essential cell division protein FtsZ have been isolated. These mutations result in the inhibition of division, accompanied by elongation into short-lived filaments, when cells are shifted from 37°C to 42°C (5).Filaments also form when the SOS response is triggered under conditions of DNA damage (6) or when the cells are treated with the antibiotic aztreonam, which blocks division irreversibly by inhibiting the FtsI protein, involved in the formation of the septal ring (7). The filaments formed under these conditions, and others, are not viable and lyse within a few hours. As a result, it was largely believed that E. coli could not sustain a large cell size.However, in this paper, we describe a mutant that forms very long viable (i.e., colony-forming) cells. This strain was derived from our earlier mutant carrying a deletion in metK, which codes for S-adenosylmethionine (SAM) synthetase; SAM is the major donor of methyl groups (8, 9). Our metK deletion mutant, MEW649, had to be exogenously provided with both SAM and methionine in order to grow, as well as with a SAM transporte...

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S-Adenosylmethionine Metabolism and Aging

Loenen

2018

Epigenetics of Aging and Longevity

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Cell division, one-carbon metabolism and methionine synthesis in a metK-deficient Escherichia coli mutant, and a role for MmuM

Cited by 9 publications

References 36 publications

A surprising range of modified-methionyl S-adenosylmethionine analogues support bacterial growth

A surprising range of modified-methionyl S-adenosylmethionine analogues support bacterial growth

An Escherichia coli Mutant That Makes Exceptionally Long Cells

S-Adenosylmethionine Metabolism and Aging

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