scholarly journals Characterization of an Escherichia coli K12 mutant that is sensitive to chlorate when grown aerobically

1978 ◽  
Vol 176 (2) ◽  
pp. 553-561 ◽  
Author(s):  
G Giordano ◽  
L Grillet ◽  
R Rosset ◽  
J H Dou ◽  
E Azoulay ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Biosynthetic Pathway ◽  
Formate Dehydrogenase ◽  
Biochemical Characterization ◽  
Reductase Activity ◽  
Growth Conditions ◽  
Aerobic Growth ◽  
Benzyl Viologen ◽  
Genetic Lesion

Escherichia coli can normally grow aerobically in the presence of chlorate; however, mutants can be isolated that can no longer grow under these conditions. We present here the biochemical characterization of one such mutant and show that the primary genetic lesion occurs in the ubiquinone-8-biosynthetic pathway. As a consequence of this, under aerobic growth conditions the mutant is apparently unable to synthesize formate dehydrogenase, but can synthesize a Benzyl Viologen-dependent nitrate reductase activity. The nature of this activity is discussed.

scholarly journals IscA/SufA paralogues are required for the [4Fe-4S] cluster assembly in enzymes of multiple physiological pathways in Escherichia coli under aerobic growth conditions

2009 ◽  
Vol 420 (3) ◽  
pp. 463-472 ◽  
Author(s):  
Guoqiang Tan ◽  
Jianxin Lu ◽  
Jacob P. Bitoun ◽  
Hao Huang ◽  
Huangen Ding
Keyword(s):  
Escherichia Coli ◽  
Cell Growth ◽  
Biosynthetic Pathway ◽  
Excision Repair ◽  
Growth Conditions ◽  
Cluster Assembly ◽  
Aerobic Growth ◽  
Aerobic Conditions ◽  
E Coli

IscA/SufA paralogues are the members of the iron-sulfur cluster assembly machinery in Escherichia coli. Whereas deletion of either IscA or SufA has only a mild effect on cell growth, deletion of both IscA and SufA results in a null-growth phenotype in minimal medium under aerobic growth conditions. Here we report that cell growth of the iscA/sufA double mutant (E. coli strain in which both iscA and sufA had been in-frame-deleted) can be partially restored by supplementing with BCAAs (branched-chain amino acids) and thiamin. We further demonstrate that deletion of IscA/SufA paralogues blocks the [4Fe-4S] cluster assembly in IlvD (dihydroxyacid dehydratase) of the BCAA biosynthetic pathway in E. coli cells under aerobic conditions and that addition of the iron-bound IscA/SufA efficiently promotes the [4Fe-4S] cluster assembly in IlvD and restores the enzyme activity in vitro, suggesting that IscA/SufA may act as an iron donor for the [4Fe-4S] cluster assembly under aerobic conditions. Additional studies reveal that IscA/SufA are also required for the [4Fe-4S] cluster assembly in enzyme ThiC of the thiamin-biosynthetic pathway, aconitase B of the citrate acid cycle and endonuclease III of the DNA-base-excision-repair pathway in E. coli under aerobic conditions. Nevertheless, deletion of IscA/SufA does not significantly affect the [2Fe-2S] cluster assembly in the redox transcription factor SoxR, ferredoxin and the siderophore-iron reductase FhuF. The results suggest that the biogenesis of the [4Fe-4S] clusters and the [2Fe-2S] clusters may have distinct pathways and that IscA/SufA paralogues are essential for the [4Fe-4S] cluster assembly, but are dispensable for the [2Fe-2S] cluster assembly in E. coli under aerobic conditions.

scholarly journals Structural and Biochemical Characterization of the Salicylyl-acyltranferase SsfX3 from a Tetracycline Biosynthetic Pathway

2011 ◽  
Vol 286 (48) ◽  
pp. 41539-41551 ◽  
Author(s):  
Lauren B. Pickens ◽  
Michael R. Sawaya ◽  
Huma Rasool ◽  
Inna Pashkov ◽  
Todd O. Yeates ◽  
...  
Keyword(s):  
Biosynthetic Pathway ◽  
Biochemical Characterization

Purification and biochemical characterization of a recombinant Anopheles gambiae tryptophan 2,3-dioxygenase expressed in Escherichia coli

2008 ◽  
Vol 38 (9) ◽  
pp. 871-876 ◽  
Author(s):  
Alessandra Paglino ◽  
Fabrizio Lombardo ◽  
Bruno Arcà ◽  
Menico Rizzi ◽  
Franca Rossi
Keyword(s):  
Escherichia Coli ◽  
Anopheles Gambiae ◽  
Biochemical Characterization

scholarly journals Aerobic Fermentation of d-Glucose by an Evolved Cytochrome Oxidase-Deficient Escherichia coli Strain

2008 ◽  
Vol 74 (24) ◽  
pp. 7561-7569 ◽  
Author(s):  
Vasiliy A. Portnoy ◽  
Markus J. Herrgård ◽  
Bernhard Ø. Palsson
Keyword(s):  
Escherichia Coli ◽  
Oxygen Uptake ◽  
Growth Conditions ◽  
Aerobic Growth ◽  
Acid Fermentation ◽  
Mixed Acid Fermentation ◽  
E Coli ◽  
Knockout Strain ◽  
Mixed Acid ◽  
Cytochrome Oxidases

ABSTRACT Fermentation of glucose to d-lactic acid under aerobic growth conditions by an evolved Escherichia coli mutant deficient in three terminal oxidases is reported in this work. Cytochrome oxidases (cydAB, cyoABCD, and cbdAB) were removed from the E. coli K12 MG1655 genome, resulting in the ECOM3 (E. coli cytochrome oxidase mutant) strain. Removal of cytochrome oxidases reduced the oxygen uptake rate of the knockout strain by nearly 85%. Moreover, the knockout strain was initially incapable of growing on M9 minimal medium. After the ECOM3 strain was subjected to adaptive evolution on glucose M9 medium for 60 days, a growth rate equivalent to that of anaerobic wild-type E. coli was achieved. Our findings demonstrate that three independently adaptively evolved ECOM3 populations acquired different phenotypes: one produced lactate as a sole fermentation product, while the other two strains exhibited a mixed-acid fermentation under oxic growth conditions with lactate remaining as the major product. The homofermenting strain showed a d-lactate yield of 0.8 g/g from glucose. Gene expression and in silico model-based analyses were employed to identify perturbed pathways and explain phenotypic behavior. Significant upregulation of ygiN and sodAB explains the remaining oxygen uptake that was observed in evolved ECOM3 strains. E. coli strains produced in this study showed the ability to produce lactate as a fermentation product from glucose and to undergo mixed-acid fermentation during aerobic growth.

scholarly journals Molecular and Biochemical Characterization of the xlnD-Encoded 3-Hydroxybenzoate 6-Hydroxylase Involved in the Degradation of 2,5-Xylenol via the Gentisate Pathway in Pseudomonas alcaligenes NCIMB 9867

2005 ◽  
Vol 187 (22) ◽  
pp. 7696-7702 ◽  
Author(s):  
Xiaoli Gao ◽  
Chew Ling Tan ◽  
Chew Chieng Yeo ◽  
Chit Laa Poh
Keyword(s):  
Escherichia Coli ◽  
Fusion Protein ◽  
Molecular Mass ◽  
Electron Donor ◽  
Biochemical Characterization ◽  
Aromatic Substrates ◽  
Gentisate Pathway ◽  
A Subunit ◽  
Pseudomonas Alcaligenes

ABSTRACT The xlnD gene from Pseudomonas alcaligenes NCIMB 9867 (strain P25X) was shown to encode 3-hydroxybenzoate 6-hydroxylase I, the enzyme that catalyzes the NADH-dependent conversion of 3-hydroxybenzoate to gentisate. Active recombinant XlnD was purified as a hexahistidine fusion protein from Escherichia coli, had an estimated molecular mass of 130 kDa, and is probably a trimeric protein with a subunit mass of 43 kDa. This is in contrast to the monomeric nature of the few 3-hydroxybenzoate 6-hydroxylases that have been characterized thus far. Like other 3-hydroxybenzoate 6-hydroxylases, XlnD could utilize either NADH or NADPH as the electron donor. P25X harbors a second 3-hydroxybenzoate 6-hydroxylase II that was strictly inducible by specific aromatic substrates. However, the degradation of 2,5-xylenol and 3,5-xylenol in strain P25X was found to be dependent on the xlnD-encoded 6-hydroxylase I and not the second, strictly inducible 6-hydroxylase II.

Sign in / Sign up

Export Citation Format

Share Document