Synthesis of pppGpp by ribosomes from an Escherichia coli spoT mutant and the metabolic relationship between pppGpp and ppGpp

1977 ◽  
Vol 55 (12) ◽  
pp. 1207-1212 ◽  
Author(s):  
Kwok-Luen Leung ◽  
Hiroshi Yamazaki
Keyword(s):  
Escherichia Coli ◽  
Gene Product ◽  
Cell Free Extract ◽  
Direct Role ◽  
Guanosine Tetraphosphate ◽  
A Cell

Both ribosomes and a cell-free extract (S-30) prepared from an Escherichia coli spoT mutant catalyzed the synthesis of guanosine pentaphosphate (pppGpp) and guanosine tetraphosphate (ppGpp) as efficiently as did ribosomes and S-30 from a spoT+ strain. In both cases, the level of pppGpp reached its maximum before ppGpp maximally accumulated. pppGpp added to the ribosome system was rapidly converted to ppGpp. These results indicate that the spoT+ gene product may not have a direct role in the synthesis of pppGpp and that pppGpp is a precursor of ppGpp.

Detection of C-P-lyase activity in a cell-free extract of Escherichia coli

2007 ◽  
Vol 43 (4) ◽  
pp. 394-398 ◽  
Author(s):  
S. V. Kononova ◽  
S. M. Trutko ◽  
K. S. Laurinavichus
Keyword(s):  
Escherichia Coli ◽  
Cell Free Extract ◽  
Lyase Activity ◽  
A Cell

scholarly journals Lack of S-Adenosylmethionine Results in a Cell Division Defect in Escherichia coli

1998 ◽  
Vol 180 (14) ◽  
pp. 3614-3619 ◽  
Author(s):  
E. B. Newman ◽  
L. I. Budman ◽  
E. C. Chan ◽  
R. C. Greene ◽  
R. T. Lin ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Gene Product ◽  
Regulatory Protein ◽  
Normal Growth ◽  
Critical Threshold ◽  
Synthetase Activity ◽  
Methyl Donor ◽  
Sam Synthetase ◽  
A Cell

ABSTRACT The enzyme S-adenosylmethionine (SAM) synthetase, theEscherichia coli metK gene product, produces SAM, the cell’s major methyl donor. We show here that SAM synthetase activity is induced by leucine and repressed by Lrp, the leucine-responsive regulatory protein. When SAM synthetase activity falls below a certain critical threshold, the cells produce long filaments with regularly distributed nucleoids. Expression of a plasmid-carried metKgene prevents filamentation and restores normal growth to themetK mutant. This indicates that lack of SAM results in a division defect.

Uridylylation of the PII protein from Herbaspirillum seropedicae

2001 ◽  
Vol 47 (4) ◽  
pp. 309-314 ◽  
Author(s):  
Elaine M Benelli ◽  
Martin Buck ◽  
Emanuel Maltempi de Souza ◽  
Marshall Geoffrey Yates ◽  
Fabio O Pedrosa
Keyword(s):  
Escherichia Coli ◽  
Signal Transduction ◽  
Nitrogen Level ◽  
Signal Transducer ◽  
Cell Free Extract ◽  
Herbaspirillum Seropedicae ◽  
Pii Protein ◽  
A Cell ◽  
Probable Role

The PII protein is apparently involved in the control of NifA activity in Herbaspirillum seropedicae. To evaluate the probable role of PII in signal transduction, uridylylation assays were conducted with purified H. seropedicae PII and Escherichia coli GlnD, or a cell-free extract of H. seropedicae as sources of uridylylating activity. The results showed that α-ketoglutarate and ATP stimulate uridylylation whereas glutamine inhibits uridylylation. Deuridylylation of PII-UMP was dependent on glutamine and inhibited by ATP and α-ketoglutarate. PII uridylylation and (or) deuridylylation in response to these effectors suggests that PII is a nitrogen level signal transducer in H. seropedicae.Key words: nitrogen regulation, uridylylation, PII protein, Herbaspirillum seropedicae.

Phosphorylation of adenosine 5′-monophosphate by a dialyzed cell-free extract from Escherichia coli

1978 ◽  
Vol 56 (8) ◽  
pp. 839-841
Author(s):  
Penu Chalykoff ◽  
Hiroshi Yamazaki
Keyword(s):  
Escherichia Coli ◽  
Cell Free Extract ◽  
Inorganic Polyphosphates ◽  
Inorganic Polyphosphate ◽  
A Cell

A cell-free extract of Escherichia coli, even after exhaustive dialysis, was found capable of phosphorylating adenosine 5′-monophosphate (AMP) to adenosine 5′-diphosphate (ADP) and adenosine 5′-triphosphate (ATP). Centrifugation at 100 000 g for 3 h sedimented most of the capacity to phosphorylate AMP to ATP, while the supernatant retained a significant capacity to phosphorylate AMP to ADP. The pellet contained a greater amount of phosphate polymers (which were neither DNA, RNA, nor proteins) than did the supernatant. The addition of authentic inorganic polyphosphates to the supernatant restored the phosphorylating capacity of the original extracts. It is concluded that the observed phosphorylation is partly due to inorganic polyphosphate.

Characterization of Escherichia coli men Mutants Defective in Conversion of o -Succinylbenzoate to 1,4-Dihydroxy-2-Naphthoate

1982 ◽  
Vol 152 (3) ◽  
pp. 1132-1137
Author(s):  
Duncan J. Shaw ◽  
John R. Guest ◽  
Rangaswamy Meganathan ◽  
Ronald Bentley
Keyword(s):  
Escherichia Coli ◽  
Vitamin K ◽  
Gene Order ◽  
Cell Free Extract ◽  
E Coli ◽  
Mycobacterium Phlei ◽  
Form Part ◽  
A Cell

Four independent menaquinone (vitamin K 2 )-deficient mutants of Escherichia coli , blocked in the conversion of o -succinylbenzoate (OSB) to 1,4-dihydroxy-2-naphthoate (DHNA), were found to represent two distinct classes. Enzymatic complementation was observed when a cell-free extract of one mutant was mixed with extracts of any of the remaining three mutants. The missing enzymes in the two classes were identified by in vitro complementation with preparations of OSB-coenzyme A (CoA) synthetase or DHNA synthase isolated from Mycobacterium phlei . Mutants lacking DHNA synthase (and therefore complementing with M. phlei DHNA synthase) were designated menB , and the mutant lacking OSB-CoA synthetase (and therefore complementing with M. phlei OSB-CoA synthetase) was designated menE . The menB mutants produced only the spirodilactone form of OSB when extracts were incubated with [2,3- 14 C 2 ]OSB, ATP, and CoA; the OSB was unchanged on incubation with an extract from the menE mutant under these conditions. Experiments with strains lysogenized by a λ men transducing phage (λG68) and transduction studies with phage P1 indicated that the menB and menE genes form part of a cluster of four genes, controlling the early steps in menaquinone biosynthesis, located at 48.5 min in the E. coli linkage map. Evidence was obtained for the clockwise gene order gyrA ....-B-D, where the asterisk denotes the uncertain position of menE relative to menC and menB . The transducing phage (λG68) contained functional menB, menC , and menE genes, but only part of the menD gene, and it was designated λ menC B(D) .

Immunodepressive activity of fractions isolated from a cell-free extract of Escherichia coli by gel filtration

1972 ◽  
Vol 74 (5) ◽  
pp. 1414-1416
Author(s):  
I. D. Kirpatovskii ◽  
E. S. Stanislavskii ◽  
G. A. Eltonskaya ◽  
V. V. Bogdanova
Keyword(s):  
Escherichia Coli ◽  
Gel Filtration ◽  
Cell Free Extract ◽  
A Cell
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