scholarly journals Amino acid residues of the Escherichia coli tRNA(m5U54)methyltransferase (TrmA) critical for stability, covalent binding of tRNA and enzymatic activity

2007 ◽  
Vol 35 (10) ◽  
pp. 3297-3305 ◽  
Author(s):  
J. Urbonavicius ◽  
G. Jager ◽  
G. R. Bjork
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Enzymatic Activity ◽  
Covalent Binding ◽  
Amino Acid Residues

Expression and partial purification of human pro-opiomelanocortin in Escherichia coli

1989 ◽  
Vol 3 (2) ◽  
pp. 105-112 ◽  
Author(s):  
T. S. Grewal ◽  
P. J. Lowry ◽  
D. Savva
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Fusion Protein ◽  
Western Blot ◽  
Blot Analysis ◽  
Expression Vectors ◽  
Partial Purification ◽  
Amino Acid Residues ◽  
E Coli ◽  
Dna Fragment

ABSTRACT A large portion of the human pro-opiomelanocortin (POMC) peptide corresponding to amino acid residues 59–241 has been cloned and expressed in Escherichia coli. A 1·0 kb DNA fragment encoding this peptide was cloned into the expression vectors pUC8 and pUR291. Plasmid pJMBG51 (a pUC8 recombinant) was found to direct the expression of a 24 kDa peptide. The recombinant pUR291 (pJMBG52) was shown to produce a β-galactosidase fusion protein of 140 kDa. Western blot analysis showed that both the 24 kDa and 140 kDa peptides are recognized by antibodies raised against POMC-derived peptides. The β-galactosidase fusion protein has been partially purified from crude E. coli cell lysates using affinity chromatography on p-aminobenzyl-1-thio-β-d-galactopyranoside agarose.

Developing structure-based models to predict substrate specificity of D-group (Type II) molybdenum enzymes: application to a molybdo-enzyme of unknown function from Archaeoglobus fulgidus

2006 ◽  
Vol 34 (1) ◽  
pp. 118-121 ◽  
Author(s):  
E.J. Dridge ◽  
D.J. Richardson ◽  
R.J. Lewis ◽  
C.S. Butler
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Sequence Analysis ◽  
Archaeoglobus Fulgidus ◽  
Substrate Selectivity ◽  
Type Ii ◽  
Amino Acid Residues ◽  
Sequence Alignments ◽  
X Ray ◽  
Group Type

The AF0174–AF0176 gene cluster in Archaeoglobus fulgidus encodes a putative oxyanion reductase of the D-type (Type II) family of molybdo-enzymes. Sequence analysis reveals that the catalytic subunit AF0176 shares low identity (31–32%) and similarity (41–42%) to both NarG and SerA, the catalytic components of the respiratory nitrate and selenate reductases respectively. Consequently, predicting the oxyanion substrate selectivity of AF0176 has proved difficult based solely on sequence alignments. In the present study, we have modelled both AF0176 and SerA on the recently determined X-ray structure of the NAR (nitrate reductase) from Escherichia coli and have identified a number of key amino acid residues, conserved in all known NAR sequences, including AF0176, that we speculate may enhance selectivity towards trigonal planar (NO3−) rather than tetrahedral (SeO42− and ClO4−) substrates.

Amino acid residues in asparaginase (Escherichia coli Hap) associated with its enzymic activity

1971 ◽  
Vol 227 (1) ◽  
pp. 171-179 ◽  
Author(s):  
Yoshihisa Nishimura ◽  
Hiroshi Makino ◽  
Osamu Takenaka ◽  
Yuji Inada
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Enzymic Activity ◽  
Amino Acid Residues

scholarly journals Diarrhea-Inducing Activity of Avian Rotavirus NSP4 Glycoproteins, Which Differ Greatly from Mammalian Rotavirus NSP4 Glycoproteins in Deduced Amino Acid Sequence, in Suckling Mice

2002 ◽  
Vol 76 (11) ◽  
pp. 5829-5834 ◽  
Author(s):  
Yoshio Mori ◽  
Mohammed Ali Borgan ◽  
Naoto Ito ◽  
Makoto Sugiyama ◽  
Nobuyuki Minamoto
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Amino Acid Sequences ◽  
Amino Acid Residues ◽  
Suckling Mice

ABSTRACT Avian rotavirus NSP4 glycoproteins expressed in Escherichia coli acted as enterotoxins in suckling mice, as did mammalian rotavirus NSP4 glycoproteins, despite great differences in the amino acid sequences. The enterotoxin domain of PO-13 NSP4 exists in amino acid residues 109 to 135, a region similar to that reported in SA11 NSP4.

scholarly journals Recovery of active beta-lactamases from Proteus vulgaris and RTEM-1 hybrid by random mutagenesis by using a dnaQ strain of Escherichia coli.

1996 ◽  
Vol 40 (9) ◽  
pp. 2152-2159 ◽  
Author(s):  
S M Hosseini-Mazinani ◽  
E Nakajima ◽  
Y Ihara ◽  
K Z Kameyama ◽  
K Sugimoto
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Random Mutagenesis ◽  
Amino Acid Residues ◽  
Proteus Vulgaris ◽  
Coding Region ◽  
Beta Lactamases ◽  
Functional Roles ◽  
Hybrid Genes ◽  
Lactamase Gene

Proteus vulgaris and RTEM-1 beta-lactamases that belong to molecular class A with 37% amino acid similarity were examined to find the relationship between amino acid residues and activity of enzymes. MICs of ampicillin were > 2,000 micrograms/ml for Escherichia coli cells producing these enzymes. We have made 18 hybrid genes by substituting the coding region of the P. vulgaris beta-lactamase gene with the equivalent portions from the RTEM-1 gene. Most of these hybrids produced inactive proteins, but a few hybrid enzymes had partial or trace activity. From one of the hybrid genes (MIC of ampicillin, 100 micrograms/ml), we recovered three kinds of active mutants which provided ampicillin MICs of 1,000 micrograms/ml by the selection of spontaneous mutations in a dnaQ strain of E. coli. In these mutants, Leu-148, Met-182, and Tyr-274 were replaced with Val, Thr, and His, respectively. These amino acids have not been identified as residues with functional roles in substrate hydrolysis. Furthermore, from these hybrid mutants, we obtained a second set of mutants which conferred ampicillin MICs of 1,500 micrograms/ml. Interestingly, the second mutations were limited to these three amino acid substitutions. These amino acid residues which do not directly interact with substrates have an effect on enzyme activity. These mutant enzymes exhibited lower K(m) values for cephaloridine than both parental enzymes.

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