Single Point Mutations at the 5′ End of a Eukaryotic Gene Can Affect Synthesis of the Gene Product In E. Coli

1988 ◽  
pp. 331-342
Author(s):  
E. M. Wright ◽  
G. T. Yarranton
Keyword(s):  
Gene Product ◽  
Single Point ◽  
Point Mutations ◽  
E Coli ◽  
Eukaryotic Gene ◽  
Single Point Mutations

scholarly journals gyrA Mutations in Ciprofloxacin-Resistant Bartonella bacilliformis Strains Obtained In Vitro

2003 ◽  
Vol 47 (1) ◽  
pp. 383-386 ◽  
Author(s):  
Michael F. Minnick ◽  
Zachary R. Wilson ◽  
Laura S. Smitherman ◽  
D. Scott Samuels
Keyword(s):  
Single Point ◽  
Point Mutations ◽  
Dna Gyrase ◽  
Wild Type ◽  
Bartonella Bacilliformis ◽  
E Coli ◽  
A Subunit ◽  
Resistant Strains ◽  
Single Point Mutations

ABSTRACT We isolated and characterized mutants of Bartonella bacilliformis that are resistant to the fluoroquinolone antibiotic ciprofloxacin, which targets the A subunit of DNA gyrase. Mutants had single point mutations in the gyrA gene that changed either Asp-90 to Gly or Asp-95 to Asn and had 3- or 16-fold higher resistance, respectively, to ciprofloxacin than did wild-type B. bacilliformis. Asp-95 is homologous to Asp-87 of Escherichia coli GyrA and is a common residue mutated in fluoroquinolone-resistant strains of other bacteria. This is the first report of a mutation at an Asp-90 homologue, which corresponds to Asp-82 in E. coli GyrA.

scholarly journals Emergence of Reduced Susceptibility and Resistance to Fluoroquinolones in Escherichia coliin Taiwan and Contributions of Distinct Selective Pressures

2001 ◽  
Vol 45 (11) ◽  
pp. 3084-3091 ◽  
Author(s):  
L. Clifford McDonald ◽  
Feng-Jui Chen ◽  
Hsiu-Jung Lo ◽  
Hsiao-Chuan Yin ◽  
Po-Liang Lu ◽  
...  
Keyword(s):  
Single Point ◽  
Point Mutations ◽  
E Coli ◽  
Hospital Acquired Infections ◽  
Selective Pressures ◽  
Adult Inpatient ◽  
Resistant Strains ◽  
Single Point Mutations ◽  
Hospital Acquired ◽  
Susceptibility And Resistance

ABSTRACT A survey of 1,203 Escherichia coli isolates from 44 hospitals in Taiwan revealed that 136 (11.3%) isolates were resistant to fluoroquinolones and that another 261 (21.7%) isolates had reduced susceptibility. Resistance was more common in isolates responsible for hospital-acquired (mostly in intensive care units) infections (17.5%) than in other adult inpatient (11.4%; P = 0.08) and outpatient isolates (11.9%; P > 0.1). Similarly, reduced susceptibility was more common in isolates responsible for hospital-acquired infections (30.9%) than in other adult inpatient (21.0%; P = 0.04) and outpatient (21.4%; P = 0.06) isolates. Isolates from pediatric patients were less likely to be resistant (1.3 versus 12.0%; P < 0.01) but were nearly as likely to have reduced susceptibility (17.7 versus 21.9%;P > 0.1) as nonpediatric isolates. There was an inverse relationship in the proportion of isolates that were resistant versus the proportion that had reduced susceptibility among isolates from individual hospitals (R = 0.031; P < 0.05). In an analysis of isolates from two hospitals, all 9 resistant strains possessed double point mutations ingyrA and all 19 strains with reduced susceptibility strains had single point mutations; no mutations were found among fully susceptible strains. Risk factors for resistance included underlying cancer (odds ratio [OR], 83; 95% confidence interval [CI95], 7.3 to 2,241; P < 0.001), exposure to a quinolone (OR, undefined; P = 0.02), and exposure to a nonquinolone antibiotic (OR, 20; CI95, 2.2 to 482; P < 0.001); underlying cancer was the only independent risk factor (OR, 83; CI95, 8.6 to 807; P < 0.001). There were no significant associations between any of these factors and reduced susceptibility. Whereas acute and chronic quinolone use in cancer patients is a major selective pressure for resistance, other undetermined but distinct selective pressures appear to be more responsible for reduced susceptibility to fluoroquinolones in E. coli.

Cupin Variants as Macromolecular Ligand Library for Stereoselective Michael Addition of Nitroalkanes

2019 ◽  
Author(s):  
Nobutaka Fujieda ◽  
Miho Yuasa ◽  
Yosuke Nishikawa ◽  
Genji Kurisu ◽  
Shinobu Itoh ◽  
...  
Keyword(s):  
Michael Addition ◽  
In Silico ◽  
Addition Reaction ◽  
Single Point ◽  
Point Mutations ◽  
Unsaturated Ketone ◽  
Michael Addition Reaction ◽  
Beta Barrel ◽  
Cupin Superfamily ◽  
Single Point Mutations

Cupin superfamily proteins (TM1459) work as a macromolecular ligand framework with a double-stranded beta-barrel structure ligating to a Cu ion through histidine side chains. Variegating the first coordination sphere of TM1459 revealed that H52A and H54A/H58A mutants effectively catalyzed the diastereo- and enantio-selective Michael addition reaction of nitroalkanes to an α,β-unsaturated ketone. Moreover, in silico substrate docking signified C106N and F104W single-point mutations, which inverted the diastereoselectivity of H52A and further improved the stereoselectivity of H54A/H58A, respectively.

Single-Point Mutations in Qβ Virus-like Particles Change Binding to Cells

2021 ◽  
Author(s):  
Marisa L. Martino ◽  
Stephen N. Crooke ◽  
Marianne Manchester ◽  
M.G. Finn
Keyword(s):  
Single Point ◽  
Point Mutations ◽  
Virus Like Particles ◽  
Single Point Mutations

MinD directly interacting with FtsZ at the H10 helix suggests a model for robust activation of MinC to destabilize FtsZ polymers

2017 ◽  
Vol 474 (18) ◽  
pp. 3189-3205 ◽  
Author(s):  
Ashoka Chary Taviti ◽  
Tushar Kant Beuria
Keyword(s):  
Cell Division ◽  
Single Point ◽  
Point Mutations ◽  
Direct Interaction ◽  
Ring Formation ◽  
Z Ring ◽  
Single Point Mutations ◽  
Biochemical Analyses ◽  
Ftsz Assembly ◽  
The Mind

Cell division in bacteria is a highly controlled and regulated process. FtsZ, a bacterial cytoskeletal protein, forms a ring-like structure known as the Z-ring and recruits more than a dozen other cell division proteins. The Min system oscillates between the poles and inhibits the Z-ring formation at the poles by perturbing FtsZ assembly. This leads to an increase in the FtsZ concentration at the mid-cell and helps in Z-ring positioning. MinC, the effector protein, interferes with Z-ring formation through two different mechanisms mediated by its two domains with the help of MinD. However, the mechanism by which MinD triggers MinC activity is not yet known. We showed that MinD directly interacts with FtsZ with an affinity stronger than the reported MinC–FtsZ interaction. We determined the MinD-binding site of FtsZ using computational, mutational and biochemical analyses. Our study showed that MinD binds to the H10 helix of FtsZ. Single-point mutations at the charged residues in the H10 helix resulted in a decrease in the FtsZ affinity towards MinD. Based on our findings, we propose a novel model for MinCD–FtsZ interaction, where MinD through its direct interaction with FtsZ would trigger MinC activity to inhibit FtsZ functions.

scholarly journals Single-point mutations of hepatitis C virus NS3 that impair p53 interaction and anti-apoptotic activity of NS3

2006 ◽  
Vol 340 (3) ◽  
pp. 792-799 ◽  
Author(s):  
Motofumi Tanaka ◽  
Motoko Nagano-Fujii ◽  
Lin Deng ◽  
Satoshi Ishido ◽  
Kiyonao Sada ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Single Point ◽  
Point Mutations ◽  
Single Point Mutations ◽  
Apoptotic Activity

scholarly journals Mutational Analysis of Quinolone-Resistant Determining Region gyrA and parC Genes in Quinolone-Resistant ESBL-Producing E. Coli

2021 ◽  
Vol 20 (3) ◽  
Author(s):  
Hairul Aini Hamzah ◽  
Rahmatullah Sirat ◽  
Mohammed Imad A. Mustafa Mahmud ◽  
Roesnita Baharudin
Keyword(s):  
Mutational Analysis ◽  
Single Point ◽  
Point Mutations ◽  
Multidrug Resistant ◽  
Quinolone Resistance ◽  
Resistant Bacteria ◽  
Single Point Mutation ◽  
Phenotypic Resistance ◽  
Drug Effectiveness ◽  
E Coli

 Introduction: Co-resistance to quinolones among extended spectrum β[1]lactamase (ESBL)-producing E. coli commonly occurs in clinical settings. Quinolones act on DNA gyrase and DNA topoisomerase enzymes, which are coded by gyrA and parC genes, thus any mutation to the genes may affect the drug effectiveness. The objective of the study was to characterize gyrA and parC genes in quinolone-resistant E. coli isolates and correlated the mutations with their phenotypic resistance. Materials and Methods: Thirty-two quinolone-resistant (QR) and six quinolone-sensitive (QS) ESBL-E. coli isolates were identified by antibiotic susceptibility and minimum inhibitory concentration tests. Bioinformatics analysis were conducted to study any mutations occurred in the genes and generate their codon compositions. Results: All the QR ESBL-E. coli isolates were identified as multidrug-resistant bacteria. A single point mutation in the quinolone resistance-determining region (QRDR) of gyrA, at codon 83, caused the substitution amino acid Ser83Leu. It is associated with a high level of resistance to nalidixic acid. However, double mutations Ser83Leu and Asp87Asn in the same region were significantly linked to higher levels of resistance to ciprofloxacin. Cumulative point mutations in gyrA and/or in parC were also correlated significantly (p<0.05) to increased resistance to ciprofloxacin. Conclusion: Together, the findings showed that the mutations in gyrA and parC genes handled the institution of intrinsic quinolone resistance in the ESBL-E. coli isolates. Thus, vigilant monitoring for emergence of new mutation in resistance genes may give an insight into dissemination of QR ESBL-E. coli in a particular region.

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