scholarly journals Specific amino acid residues in both the PstB and PstC proteins are required for phosphate transport by the Escherichia coli Pst system.

1989 ◽  
Vol 171 (3) ◽  
pp. 1531-1534 ◽  
Author(s):  
G B Cox ◽  
D Webb ◽  
H Rosenberg
1989 ◽  
Vol 3 (2) ◽  
pp. 105-112 ◽  
Author(s):  
T. S. Grewal ◽  
P. J. Lowry ◽  
D. Savva

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.


2006 ◽  
Vol 34 (1) ◽  
pp. 118-121 ◽  
Author(s):  
E.J. Dridge ◽  
D.J. Richardson ◽  
R.J. Lewis ◽  
C.S. Butler

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.


1971 ◽  
Vol 227 (1) ◽  
pp. 171-179 ◽  
Author(s):  
Yoshihisa Nishimura ◽  
Hiroshi Makino ◽  
Osamu Takenaka ◽  
Yuji Inada

2019 ◽  
Author(s):  
Hadeel Gassim Hassan ◽  
Abeer Babiker Idris ◽  
Mohamed A. Hassan ◽  
Hisham N. Altayb ◽  
Kyakonye Yasin ◽  
...  

AbstractBackgroundThere is an increase in the prevalence of Helicobacter pylori infection in Sudan, accompanied by a high incidence of upper gastrointestinal malignancy. The cytotoxin-associated gene cagA gene is a marker of a pathogenicity island (PAI) in H. pylori and plays a crucial role in determining the clinical outcome of Helicobacter infections.ObjectiveThis study aimed to determine the frequency and heterogeneity of the cagA gene of H. pylori and correlate the presence of cagA gene with clinical outcomes.Materials and methodsFifty endoscopy biopsies were collected from Fedail and Soba hospitals in Khartoum state. DNA was extracted using the Guanidine chloride method followed by PCR to amplify 16S rRNA and cagA gene of H. pylori using specific primers. DNA amplicons of cagA gene were purified and sequenced. Bioinformatics and statistical analysis were done to characterize and to test the association between cagA gene and gastric complications.ResultsCagA gene was detected in 20/37(54%) of the samples that were found positive for H. pylori. There was no association between endoscopy finding and the presence of the cagA gene (p = 0.225). Specific amino acid variations were found at seven loci related to strains from a patient with duodenitis, gastric ulcer, and gastric atrophy (R448H, T457K, S460L, IT463-464VA, D470E, A482Q, KNV490-491-492TKT) while mutations in cancerous strain were A439P, T457P, and H500Y.ConclusionDisease-specific variations of cagA of H. pylori strains, in the region of amino acid residues 428-510, were evident among Sudanese patients with different gastroduodenal diseases. A novel mutation (K458N) was detected in a patient with duodenitis, which affects the positive electrostatic surface of cagA. Phylogenetic analysis showed a high level of diversity of cagA from Sudanese H. pylori strains.


2002 ◽  
Vol 76 (11) ◽  
pp. 5829-5834 ◽  
Author(s):  
Yoshio Mori ◽  
Mohammed Ali Borgan ◽  
Naoto Ito ◽  
Makoto Sugiyama ◽  
Nobuyuki Minamoto

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.


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