E. coli Thioredoxin Stability Is Greatly Enhanced by Substitution of Aspartic Acid 26 by Alanine

1990 ◽  
pp. 449-456 ◽  
Author(s):  
Knut Langsetmo ◽  
Young-Chul Sung ◽  
James Fuchs ◽  
Clare Woodward
Keyword(s):  
Aspartic Acid ◽  
E Coli

Some enzymic syntheses of 15N-L-aspartic acid and 15N-L-glutamic acid

1969 ◽  
Vol 47 (3) ◽  
pp. 411-415 ◽  
Author(s):  
J. A. Zintel ◽  
A. J. Williams ◽  
R. S. Stuart
Keyword(s):  
Glutamic Acid ◽  
Aspartic Acid ◽  
Fumaric Acid ◽  
Aspartate Aminotransferase ◽  
Efficient Utilization ◽  
E Coli ◽  
Acid Dehydrogenase ◽  
Acid Catalyzed ◽  
Catalyzed Reactions ◽  
Enzyme Catalyzed Reactions

Some methods for the preparation of 15N-L-aspartic acid and 15N-L-glutamic acid using enzyme catalyzed reactions are described. 15N-L-Aspartic acid is prepared by the addition of ammonia to fumaric acid, catalyzing the reaction with aspartase which was partially purified from E. coli. 15N-L-Glutamic acid with a high 15N/14N ratio is prepared by transamination with 15N-L-aspartic acid catalyzed by aspartate aminotransferase. 15N-L-Glutamic acid with a low 15N/14N ratio is prepared by a glutamic acid dehydrogenase catalyzed exchange of L-glutamic acid with 15N-ammonia. These enzymes are commercially available. Since efficient utilization of 15N is obtained, aspartic acid or glutamic acid may be prepared with any desired 15N/14N ratio.

Stoffwechselregulation durch den Zellwandbaustein Kieselsäure: Polgrößenänderungen von a-Ketoglutarsäure, Aminosäuren und Nucleosidphosphaten

1968 ◽  
Vol 23 (2) ◽  
pp. 268-271 ◽  
Author(s):  
D. Werner
Keyword(s):  
Glutamic Acid ◽  
Aspartic Acid ◽  
Rna Synthesis ◽  
Acid Synthesis ◽  
Centric Diatom ◽  
Free Medium ◽  
Acetyl Coa ◽  
E Coli ◽  
Acid Pool ◽  
Acetyl Coa Pathway

When the centric diatom Cyclotella cryptica is grown in a Si (OH) 4-free medium, the glutamic acid pool decreases within 3 hours to a third of the original value, whereas the aspartic acid pool is reduced by only about 20 per cent. The pools of nucleosid-triphosphates and of glycerol-1-phosphate remain unaffected during this time. The nucleosid-diphosphates pool decreases in the same way as that of aspartic acid. The decrease in the glutamic acid pool precedes the inhibition of total protein synthesis in Si (OH) 4-deficient cells, and a significant decrease in the a-ketoglutarate pool precedes the decrease of the glutamic acid content. Already within 60 minutes ofter incubation in a Si (OH) 4-free medium, the content of a-ketoglutarate is decreased to one third of the normal value. On the other hand, the acetyl CoA pathway (enhanced fatty acid synthesis) is not inhibited. The results suggest, that the Si (OH) 4-metabolism interferes with reactions between the condensing enzyme (acetyl-CoA and oxalacetate) and a-ketoglutarate. The delay between inhibition of protein- and RNA-synthesis and the different changes in the pools of amino acids and nucleosid-triphosphates resemble the regulation of the nucleosid-triphosphate pool and RNA-synthesis in amino acid starved strains of E. coli (EDLIN and NEUHARD) 1, though the primary causes are quite different.

scholarly journals Mutagenesis of the l-Amino Acid Ligase RizA Increased the Production of Bioactive Dipeptides

Catalysts ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1385
Author(s):  
Sven Bordewick ◽  
Ralf G. Berger ◽  
Franziska Ersoy
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Aspartic Acid ◽  
Product Yield ◽  
Binding Pocket ◽  
Site Directed Mutagenesis ◽  
Product Concentration ◽  
Substrate Binding Pocket ◽  
E Coli ◽  
Set Up

The l-amino acid ligase RizA from B. subtilis selectively synthesizes dipeptides containing an N-terminal arginine. Many arginyl dipeptides have salt-taste enhancing properties while Arg-Phe has been found to have an antihypertensive effect. A total of 21 RizA variants were created by site-directed mutagenesis of eight amino acids in the substrate binding pocket. The variants were recombinantly produced in E. coli and purified by affinity chromatography. Biocatalytic reactions were set up with arginine and four amino acids differing in size and polarity (aspartic acid, serine, alanine, and phenylalanine) and were analyzed by RP-HPLC with fluorescence detection. Variant T81F significantly improved the yield in comparison to wild type RizA for aspartic acid (7 to 17%), serine (33 to 47%) and alanine (12 to 17%). S84F increased product yield similarly for aspartic acid (7 to 17%) and serine (33 to 42%). D376E increased the yield with alanine (12 to 19%) and phenylalanine (11 to 26%). The largest change was observed for S156A, which showed a yield for Arg-Phe of 40% corresponding to a 270% increase in product concentration. This study expands the knowledge about positions governing the substrate specificity of RizA and may help to inform future protein engineering endeavors.

scholarly journals Characterization of PitA and PitB fromEscherichia coli

2001 ◽  
Vol 183 (17) ◽  
pp. 5008-5014 ◽  
Author(s):  
Robyn M. Harris ◽  
Dianne C. Webb ◽  
Susan M. Howitt ◽  
Graeme B. Cox
Keyword(s):  
Aspartic Acid ◽  
Base Change ◽  
Triple Mutant ◽  
E Coli ◽  
Uptake Rates ◽  
Single Base Change ◽  
K 12 ◽  
Pst System ◽  
Protein Strain

ABSTRACT Escherichia coli contains two major systems for transporting inorganic phosphate (Pi). The low-affinity Pi transporter (pitA) is expressed constitutively and is dependent on the proton motive force, while the high-affinity Pst system (pstSCAB) is induced at low external Pi concentrations by the phoregulon and is an ABC transporter. We isolated a third putative Pi transport gene, pitB, from E. coli K-12 and present evidence that pitB encodes a functional Pi transporter that may be repressed at low Pi levels by the pho regulon. While apitB + cosmid clone allowed growth on medium containing 500 μM Pi, E. coli with wild-type genomic pitB (pitAΔpstC345 double mutant) was unable to grow under these conditions, making it indistinguishable from a pitA pitBΔpstC345 triple mutant. The mutation ΔpstC345 constitutively activates thepho regulon, which is normally induced by phosphate starvation. Removal of pho regulation by deleting thephoB-phoR operon allowed thepitB + pitAΔpstC345 strain to utilize Pi, with Pi uptake rates significantly higher than background levels. In addition, the apparent K m of PitB decreased with increased levels of protein expression, suggesting that there is also regulation of the PitB protein. Strain K-10 contains a nonfunctional pitA gene and lacks Pit activity when the Pst system is mutated. The pitAmutation was identified as a single base change, causing an aspartic acid to replace glycine 220. This mutation greatly decreased the amount of PitA protein present in cell membranes, indicating that the aspartic acid substitution disrupts protein structure.

scholarly journals The Role of Aspartic Acid 143 in E. coli tRNA-Guanine Transglycosylase: Insights from Mutagenesis Studies and Computational Modeling

2005 ◽  
Vol 89 (3) ◽  
pp. 1965-1977 ◽  
Author(s):  
Katherine Abold Todorov ◽  
Xiao-Jian Tan ◽  
Susanne T. Nonekowski ◽  
George A. Garcia ◽  
Heather A. Carlson
Keyword(s):  
Computational Modeling ◽  
Aspartic Acid ◽  
E Coli

scholarly journals Über Aminosäure-Antagonisten, III Synthese von 4-Alkoxy-2-oxo-trans-3-butensäurealkylestern / On Amino Acid Antagonists, III Syntheses of 4-Alkoxy-2-oxo-trans-3-butenoic Acid Esters

1977 ◽  
Vol 32 (9) ◽  
pp. 1068-1071 ◽  
Author(s):  
Wolfram Trowitzsch
Keyword(s):  
Amino Acid ◽  
Nmr Spectroscopy ◽  
Aspartic Acid ◽  
Biologically Active ◽  
Oxalacetic Acid ◽  
E Coli ◽  
Active Esters ◽  
Butenoic Acid ◽  
Amino Acid Antagonists ◽  
Acid Esters

The syntheses of the above biologically active esters are described. By NMR spectroscopy it is shown that the corresponding ethyl compound 4 may exist in both the trans and the cis conformers. Starting with 4, addition of an appropriate alcohol results in the corresponding 4-alkoxy compound of 4. The described esters are antagonists of aspartic acid as well as of oxalacetic acid and inhibited the growth of E. coli MRE 600.

L-Aspartic Acid Production Using Immobilized E. coli Cells in a Packed-Bed Reactor.

1990 ◽  
Vol 589 (1 Biochemical E) ◽  
pp. 540-552 ◽  
Author(s):  
HIROYASU SEKO ◽  
SHINOBU TAKEUCHI ◽  
KAZUYOSHI YAJIMA ◽  
MASARU SENUMA ◽  
TETSUYA TOSA
Keyword(s):  
Aspartic Acid ◽  
Acid Production ◽  
Packed Bed ◽  
Packed Bed Reactor ◽  
E Coli

Endotoxin Alteration of the Mucopolysaccharide Blood Vessel Coating in Rats

1974 ◽  
Vol 32 ◽  
pp. 148-149
Author(s):  
D. E. Philpott ◽  
A. Takahashi
Keyword(s):  
Skeletal Muscle ◽  
Endothelial Cells ◽  
Salivary Gland ◽  
Carotid Artery ◽  
Basement Membrane ◽  
Coronary Vessels ◽  
Ruthenium Red ◽  
E Coli ◽  
Old Rats ◽  
The Brain

Two month, eight month and two year old rats were treated with 10 or 20 mg/kg of E. Coli endotoxin I. P. The eight month old rats proved most resistant to the endotoxin. During fixation the aorta, carotid artery, basil arartery of the brain, coronary vessels of the heart, inner surfaces of the heart chambers, heart and skeletal muscle, lung, liver, kidney, spleen, brain, retina, trachae, intestine, salivary gland, adrenal gland and gingiva were treated with ruthenium red or alcian blue to preserve the mucopolysaccharide (MPS) coating. Five, 8 and 24 hrs of endotoxin treatment produced increasingly marked capillary damage, disappearance of the MPS coating, edema, destruction of endothelial cells and damage to the basement membrane in the liver, kidney and lung.

Ribosome Structural Organization

1974 ◽  
Vol 32 ◽  
pp. 332-333
Author(s):  
James A. Lake
Keyword(s):  
Ribosomal Proteins ◽  
Structural Organization ◽  
Three Dimensional ◽  
Small Subunit ◽  
Structural Studies ◽  
X Ray Diffraction ◽  
Specific Antibodies ◽  
X Ray ◽  
E Coli ◽  
Complete Sequences

The understanding of ribosome structure has advanced considerably in the last several years. Biochemists have characterized the constituent proteins and rRNA's of ribosomes. Complete sequences have been determined for some ribosomal proteins and specific antibodies have been prepared against all E. coli small subunit proteins. In addition, a number of naturally occuring systems of three dimensional ribosome crystals which are suitable for structural studies have been observed in eukaryotes. Although the crystals are, in general, too small for X-ray diffraction, their size is ideal for electron microscopy.

Sign in / Sign up

Export Citation Format

Share Document