Heat-induced unfolding of apo-CP43 studied by fluorescence spectroscopy and CD spectroscopy

Xiao, Qing-Jie; Li, Zai-Geng; Yang, Jiao; He, Quanguo; Xi, Lei; Du, Linfang

doi:10.1007/s11120-015-0166-1

Cited by 12 publications

(6 citation statements)

References 47 publications

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“…Several results suggest that aptamer C07 in this study can recognize and bind to the target Sudan III. Therefore, an aptamer C07 for rapid detection of Sudan III may develop in the food field …”

Section: Resultsmentioning

confidence: 99%

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Screening and Application of a New Aptamer for the Rapid Detection of Sudan Dye III

Wang

Qiao

et al. 2018

Euro J Lipid Sci & Tech

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Sudan dye is generally used as a coloring agent in textile and cosmetic industries. However, Sudan dye exhibits potentials to cause cancer, toxicity, and allergy because of its metabolites including amines and naphthol related substances. Despite banning Sudan dye, the Sudan dye is used by many unscrupulous food manufacturers for enhancing food appearance. This paper introduces a new aptamer based on Sudan III detection methods. An in vitro selection and amplification method named SELEX (Systematic Evolution of Ligands by Exponential Enrichment) is employed to screen out Sudan III specific aptamer. The desired aptamer is obtained after 12 rounds of screening and cloning. To establish aptamer affinity and specificity for Sudan III, ELONA (enzyme‐linked oligonucleotide assay) and dot blot analyses are performed. ELONA assay indicates that 100 nM is the optimum concentration of the aptamer for Sudan III detection, while the minimum detection limit of Sudan III is 4 ng/well. The aptamer exhibits stable secondary structure with the stem‐loop and G‐quadruplex in the main structure. The selected single ssDNA aptamer C07 demonstrates binding affinity and the highest specificity to Sudan III (C07: KD = 22.37 ± 3.943 nmol L−1). Based on the results, a good correlation is observed between aptamer C07 and Sudan III and it is concluded that the new Sudan III specific aptamer has potential to be applied for rapid and accurate detection of the Sudan III in food products. Practical Applications: Examination of the chili sauce sample in a simulation experiment indicates that the aptamer C07 can be applied to rapid detection in foods. The nucleic acid aptamers‐based food detection method has the advantages of high sensitivity, specificity, easy operation, short detection time, and low cost. It can realize the rapid detection of illegal additives in foods, which has a great significance in the field of food safety research. The SELEX method is used to select a new Sudan III specific aptamer. ELONA and Dot blot assays further suggest that aptamer C07 can be used for selective detection of Sudan III. Therefore, the detection in chili sauce samples offers feasibility for more complex samples.

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Section: Resultsmentioning

confidence: 99%

“…All may have a profound effect on the stability of aptamer C07. [33] 3. [31,32] Similarly, in this study, the conserved sequence residing at the stem-and-loop structures of the DNA aptamer may represent the active binding sites.…”

Section: Sequencing and Structure Analysismentioning

confidence: 99%

Screening and Application of a New Aptamer for the Rapid Detection of Sudan Dye III

Wang

Qiao

et al. 2018

Euro J Lipid Sci & Tech

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“…Therefore, intrinsic tryptophan fluorescence emission is sensitive to the tertiary structure and detects subtle protein conformational changes in solution. It has been frequently used for the characterization of protein's conformational changes under different stress conditions (Kumar et al 2005;Xiao et al 2015).…”

Section: Resultsmentioning

confidence: 99%

MERS‐CoV papain-like protease (PLpro): expression, purification, and spectroscopic/thermodynamic characterization

Malik

Alsenaidy

2017

3 Biotech

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Within a decade, MERS-CoV emerged with nearly four times higher case fatality rate than an earlier outbreak of SARS-CoV and spread out in 27 countries in short span of time. As an emerging virus, combating it requires an in-depth understanding of its molecular machinery. Therefore, conformational characterization studies of coronavirus proteins are necessary to advance our knowledge of the matter for the development of antiviral therapies. In this study, MERS-CoV papain-like protease (PL pro ) was recombinantly expressed and purified. Thermal folding pathway and thermodynamic properties were characterized using dynamic multimode spectroscopy (DMS) and thermal shift assay. DMS study showed that the PL pro undergoes a single thermal transition and follows a pathway of two-state folding with T m and van't Hoff enthalpy values of 54.4 ± 0.1°C and 317.1 ± 3.9 kJ/mol, respectively. An orthogonal technique based on intrinsic tryptophan fluorescence also showed that MERS-CoV PL pro undergoes a single thermal transition and unfolds via a pathway of two-state folding with a T m value of 51.4°C. Our findings provide significant understandings of the thermodynamic and structural properties of MERS-CoV PL pro .

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“…To further investigate the flexible nature of the 73–86 loop, an intrinsic tryptophan fluorescence assay was carried out for rSgrA 28–153 . The exposure of tryptophan residues to the aqueous environment leads to changes in the intensity of fluorescence emission . As the 73–86 loop contains a tryptophan, any conformational change of the loop may contribute to variations in the fluorescence intensity.…”

Section: Resultsmentioning

confidence: 99%

The crystal structure of the ligand‐binding region of serine‐glutamate repeat containing protein A (SgrA) of Enterococcus faecium reveals a new protein fold: functional characterization and insights into its adhesion function

2016

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Antimicrobial-resistant and hospital-adapted Enterococcus faecium represents a clinical problem in immunocompromised patients in hospitals worldwide. Understanding the molecular pathogenesis of E. faecium infections may provide novel therapies to treat or prevent infections. A potential target for novel treatment therapies is the serine-glutamate repeat containing protein A (SgrA), which is a cell wall-anchored LPxTG surface protein implicated in binding to fibrinogen and nidogen. Here, we report the X-ray crystal structure of the N-terminal ligand-binding domain of SgrA (rSgrA ) to a resolution of 1.79A. The structure revealed a new protein fold with significant differences from previously characterized DEvIgG-and inv-IgG-like folds of adhesive proteins known as microbial surface components recognizing adhesive matrix molecules. The structure contains a Lys-Asn-Glu triad with the potential to form a Lys-Asn isopeptide bond. However, even in the absence of a stabilizing intramolecular isopeptide bond, rSgrA 28-153 exhibits remarkable properties like resistance to proteases and high thermal stability. The interaction of rSgrA with fibrinogen, nidogen, laminin, and abiotic surfaces has been characterized and rSgrA binds to these molecules with high affinity. rSgrA 28-153 also binds to the beta chain of fibrinogen and with high affinity and specificity. Strikingly, the presence of 29 surface-exposed hydrophobic amino acid residues likely play an important role in the selectivity of rSgrA to bind to different abiotic surfaces. The results obtained from this study have opened new avenues to explore and understand the role of this unique surface adhesin in the pathogenesis of catheter-related infections. PDB accession codeThe coordinates and structure factors for rSgrA have been deposited with the accession code 5FCE.

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Heat-induced unfolding of apo-CP43 studied by fluorescence spectroscopy and CD spectroscopy

Cited by 12 publications

References 47 publications

Screening and Application of a New Aptamer for the Rapid Detection of Sudan Dye III

Screening and Application of a New Aptamer for the Rapid Detection of Sudan Dye III

MERS‐CoV papain-like protease (PLpro): expression, purification, and spectroscopic/thermodynamic characterization

The crystal structure of the ligand‐binding region of serine‐glutamate repeat containing protein A (SgrA) of Enterococcus faecium reveals a new protein fold: functional characterization and insights into its adhesion function

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