scholarly journals Acute regulation of mouse AE2 anion exchanger requires isoform-specific amino acid residues from most of the transmembrane domain

2007 ◽  
Vol 584 (1) ◽  
pp. 59-73 ◽  
Author(s):  
A. K. Stewart ◽  
C. E. Kurschat ◽  
R. D. Vaughan-Jones ◽  
B. E. Shmukler ◽  
S. L. Alper
Keyword(s):  
Amino Acid ◽  
Anion Exchanger ◽  
Transmembrane Domain ◽  
Amino Acid Residues ◽  
Specific Amino Acid

scholarly journals Charged Residues Flanking the Transmembrane Domain of Two Related Toxin–Antitoxin System Toxins Affect Host Response

Toxins ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 329
Author(s):  
Andrew Holmes ◽  
Jessie Sadlon ◽  
Keith Weaver
Keyword(s):  
Amino Acid ◽  
Enterococcus Faecalis ◽  
Host Response ◽  
Cytoplasmic Membrane ◽  
Transmembrane Domain ◽  
The Other ◽  
Type I ◽  
Transcriptomic Response ◽  
Specific Amino Acid ◽  
Transporter Protein

A majority of toxins produced by type I toxin–antitoxin (TA-1) systems are small membrane-localized proteins that were initially proposed to kill cells by forming non-specific pores in the cytoplasmic membrane. The examination of the effects of numerous TA-1 systems indicates that this is not the mechanism of action of many of these proteins. Enterococcus faecalis produces two toxins of the Fst/Ldr family, one encoded on pheromone-responsive conjugative plasmids (FstpAD1) and the other on the chromosome, FstEF0409. Previous results demonstrated that overexpression of the toxins produced a differential transcriptomic response in E. faecalis cells. In this report, we identify the specific amino acid differences between the two toxins responsible for the differential response of a gene highly induced by FstpAD1 but not FstEF0409. In addition, we demonstrate that a transporter protein that is genetically linked to the chromosomal version of the TA-1 system functions to limit the toxicity of the protein.

scholarly journals Genetic Diversity of the cagA gene of Helicobacter pylori strains from Sudanese Patients with Different Gastroduodenal Diseases

2019 ◽  
Author(s):  
Hadeel Gassim Hassan ◽  
Abeer Babiker Idris ◽  
Mohamed A. Hassan ◽  
Hisham N. Altayb ◽  
Kyakonye Yasin ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Amino Acid ◽  
Novel Mutation ◽  
Amino Acid Residues ◽  
Specific Amino Acid ◽  
Gastrointestinal Malignancy ◽  
High Incidence ◽  
H Pylori ◽  
High Level ◽  
Chloride Method

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.

A Mutation in the  Subunit of the Platelet Integrin IIbβ3 Identifies a Novel Region Important for Ligand Binding

Blood ◽  
1999 ◽  
Vol 93 (3) ◽  
pp. 918-924 ◽  
Author(s):  
Eileen Collins Tozer ◽  
Elizabeth K. Baker ◽  
Mark H. Ginsberg ◽  
Joseph C. Loftus
Keyword(s):  
Amino Acid ◽  
Ligand Binding ◽  
Single Amino Acid ◽  
Chimeric Receptor ◽  
Amino Acid Residues ◽  
Genetic Approach ◽  
Specific Amino Acid ◽  
Transfected Cells ◽  
Binding Function ◽  
A Cell

Abstract An unbiased genetic approach was used to identify a specific amino acid residue in the IIb subunit important for the ligand binding function of the integrin IIbβ. Chemically mutagenized cells were selected by flow cytometry based on their inability to bind the ligand mimetic antibody PAC1 and a cell line containing a single amino acid substitution in IIb at position 224 (D→V) was identified. Although well expressed on the surface of transfected cells, IIbD224Vβ3 as well as IIbD224Aβ3 did not bind IIbβ3-specific ligands or a RGD peptide, a ligand shared in common with vβ3. Insertion of exon 5 of IIb, residues G193-W235, into the backbone of the v subunit did not enable the chimeric receptor to bind IIbβ3-specific ligands. However, the chimeric receptor was still capable of binding to a RGD affinity matrix. IIbD224 is not well conserved among other integrin  subunits and is located in a region of significant variability. In addition, amino acid D224 lies within a predicted loop of the recently proposed β-propeller model for integrin  subunits and is adjacent to a loop containing amino acid residues previously implicated in receptor function. These data support a role for this region in ligand binding function of the IIbβ3 receptor.

scholarly journals PC8 [corrected], a new member of the convertase family

1996 ◽  
Vol 314 (3) ◽  
pp. 727-731 ◽  
Author(s):  
Angela BRUZZANITI ◽  
Katrina GOODGE ◽  
Philippe JAY ◽  
Sylvie A. TAVIAUX ◽  
Mark H. C. Lam ◽  
...  
Keyword(s):  
Amino Acid ◽  
Transmembrane Domain ◽  
Duplication Event ◽  
Amino Acid Identity ◽  
Chromosome 15 ◽  
Rat Tissues ◽  
Amino Acid Residues ◽  
Degenerate Primers ◽  
Chromosome 11Q23 ◽  
Ancient Gene Duplication

A novel subtilisin-like protein, PC8, was identified by PCR using degenerate primers to conserved amino acid residues in the catalytic region of members of the prohormone convertase family. PC8 was predicted to be 785 residues long and was structurally related to the mammalian convertases furin, PACE4, PC1 and PC2, sharing more than 50% amino acid identity over the catalytic region with these family members. PC8 possessed the catalytically important Asp, His, Asn and Ser amino acids, the homo B domain of this family of enzymes and a C-terminal hydrophobic sequence indicative of a transmembrane domain. Structurally, PC8 is more related to furin and PACE4 than to PC1 or PC2. Like furin and PACE4, PC8 mRNA was found to be widely expressed; this is in contrast with PC1 and PC2, which have a restricted distribution. Two transcripts, of 4.5 and 3.5 kb, were detected in both human cell lines and rat tissues. Unlike furin and PACE4, both of which map to chromosome 15, PC8 maps to chromosome 11q23–11q24, suggesting that this gene may have resulted from an ancient gene duplication event from either furin or PACE4, or conversely that these genes arose from PC8.

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