Weakly Coupled Biologically Relevant CuII2(μ-η1:η1-O2) cis-Peroxo Adduct that Binds Side-On to Additional Metal Ions

2014 ◽  
Vol 136 (20) ◽  
pp. 7428-7434 ◽  
Author(s):  
Kristian E. Dalle ◽  
Tim Gruene ◽  
Sebastian Dechert ◽  
Serhiy Demeshko ◽  
Franc Meyer
Keyword(s):  
Metal Ions ◽  
Biologically Relevant ◽  
Weakly Coupled

Electrochemical characterization of Cu(II) complexes of brain-related tau peptides

2021 ◽  
Vol 99 (7) ◽  
pp. 628-636
Author(s):  
Camilla Golec ◽  
Jose O. Esteves-Villanueva ◽  
Sanela Martic
Keyword(s):  
Metal Ions ◽  
Tau Protein ◽  
Metal Ion ◽  
Differential Pulse ◽  
Redox Couple ◽  
Peptide Sequence ◽  
Binding Studies ◽  
Biologically Relevant ◽  
Redox Active ◽  
Competition Binding

Metal ion dyshomeostasis plays an important role in diseases, including neurodegeneration. Tau protein is a known neurodegeneration biomarker, but its interactions with biologically relevant metal ions, such as Cu(II), are not fully understood. Herein, the Cu(II) complexes of four tau R peptides, based on the tau repeat domains, R1, R2, R3, and R4, were characterized by electrochemical methods, including cyclic voltammetry, square-wave voltammetry, and differential pulse voltammetry in solution under aerobic conditions. The current and potential associated with Cu(II)/(I) redox couple was modulated as a function of R peptide sequence and concentration. All R peptides coordinated Cu(II) resulting in a dramatic decrease in the current associated with free Cu(II), and the appearance of a new redox couple due to metallo–peptide complex. The metallo–peptide complexes were characterized by the irreversible redox couple at more positive potentials and slower electron-transfer rates compared with the free Cu(II). The competition binding studies between R peptides with Cu(II) indicated that the strongest binding affinity was observed for the R3 peptide, which contained 2 His and 1 Cys residues. The formation of complexes was also evaluated as a function of peptide concentration and in the presence of competing Zn(II) ions. Data indicate that all metallo–peptides remain redox active pointing to the potential importance of the interactions between tau protein with metal ions in a biological setting.

Interaction energies between metal ions (Zn2+ and Cd2+ ) and biologically relevant ligands

2013 ◽  
Vol 113 (23) ◽  
pp. 2554-2562 ◽  
Author(s):  
Emma Ahlstrand ◽  
Daniel Spångberg ◽  
Kersti Hermansson ◽  
Ran Friedman
Keyword(s):  
Metal Ions ◽  
Interaction Energies ◽  
Biologically Relevant

Polythiol binding to biologically relevant metal ions

2011 ◽  
Vol 40 (40) ◽  
pp. 10434 ◽  
Author(s):  
Karolina Krzywoszynska ◽  
Magdalena Rowinska-Zyrek ◽  
Danuta Witkowska ◽  
Slawomir Potocki ◽  
Marek Luczkowski ◽  
...  
Keyword(s):  
Metal Ions ◽  
Biologically Relevant

scholarly journals Low-generation dendrimers with a calixarene core and based on a chiral C 2-symmetric pyrrolidine as iminosugar mimics

2012 ◽  
Vol 8 ◽  
pp. 951-957 ◽  
Author(s):  
Marco Marradi ◽  
Stefano Cicchi ◽  
Francesco Sansone ◽  
Alessandro Casnati ◽  
Andrea Goti
Keyword(s):  
Alkali Metal ◽  
Metal Ions ◽  
Alkali Metal Ions ◽  
Biologically Relevant ◽  
Reduced Volume ◽  
Sodium And Potassium ◽  
Rapid Incorporation

The preparation of low-generation dendrimers based on a simple calix[4]arene scaffold by insertion of the iminosugar-analogue C 2-symmetric 3,4-dihydroxypyrrolidine is described. This methodology allows a rapid incorporation of a considerable number of iminosugar-like moieties in a reduced volume and in a well-defined geometry. The inclusion of alkali-metal ions (sodium and potassium) in the polar cavity defined by the acetamide moieties at the lower rim of the calixarene was demonstrated, which allows also the rigidification of the dendrimer structure and the iminosugar presentation in the clusters. The combination of the supramolecular properties of calixarenes with the advantage of a dendrimeric presentation of repetitive units opens up the possibility of generating well-defined multivalent and multifaceted systems with more complex and/or biologically relevant iminosugars.

Rhodamine based turn-on chemosensor for Fe3+ in aqueous medium and interactions of its Fe3+ complex with DNA

2018 ◽  
Vol 42 (5) ◽  
pp. 3435-3443 ◽  
Author(s):  
Rahul Bhowmick ◽  
Abu Saleh Musha Islam ◽  
Urmila Saha ◽  
Gopinatha Suresh Kumar ◽  
Mahammad Ali
Keyword(s):  
Metal Ions ◽  
Aqueous Medium ◽  
Reactive Oxygen ◽  
Toxic Metal ◽  
Nitrogen Species ◽  
No Donor ◽  
Toxic Metal Ions ◽  
Biologically Relevant ◽  
Turn On

A novel di-coordinating rhodamine-based chemosensor, HL with NO donor atoms, selectively and rapidly recognizes Fe3+ in the presence of all biologically relevant as well as toxic metal ions and numerous anions and also with other reactive oxygen and nitrogen species.

Surfactant modulated aggregation induced enhancement of emission (AIEE)—a simple demonstration to maximize sensor activity

The Analyst ◽  
2016 ◽  
Vol 141 (1) ◽  
pp. 225-235 ◽  
Author(s):  
Rahul Bhowmick ◽  
Abu Saleh Musha Islam ◽  
Atul Katarkar ◽  
Keya Chaudhuri ◽  
Mahammad Ali
Keyword(s):  
Heavy Metals ◽  
Detection Limit ◽  
Metal Ions ◽  
Cell Imaging ◽  
Toxic Heavy Metals ◽  
Biologically Relevant ◽  
Simple Demonstration

A rhodamine-based chemosensor, L3, selectively and rapidly recognizes Hg2+ ions in the presence of all biologically relevant metal ions and toxic heavy metals with a detection limit of 78 nM along with possessing cytoplasmic cell imaging applications.

Study on the Development of a Cyclohexane Based Tripodal Molecular Device as "OFF-ON-OFF" pH Sensor and Fluorescent Iron Sensor

2020 ◽  
Vol 16 (5) ◽  
pp. 620-630 ◽  
Author(s):  
Vijay Dangi ◽  
Minati Baral ◽  
B.K. Kanungo
Keyword(s):  
Metal Ions ◽  
Ph Sensor ◽  
Maximum Deviation ◽  
Theoretical Studies ◽  
Dft Studies ◽  
Binding Studies ◽  
Deprotonated Form ◽  
Weak Band ◽  
Biologically Relevant ◽  
Td Dft

Background: Iron is an essential transition metal which is indispensable for life processes like oxygen transport and metabolism, electron transfer etc. However, misregulated iron is responsible for disease like anemia, hemochromatosis, Alzheimer’s and Parkinson’s disease. In order to encounter these diseases, a better understanding is needed of its role in misregulation. Fluorescent iron sensors could help provide this information. The new chemosensor developed by linking a cyclohexane unit with three 8-hydroxyquinoline provides selective detection of iron in numerous biological and environmental samples. Methods: The Uv-visible and fluorescence spectroscopy in combination with pH measurements will mainly be used for the study. Theoretical studies at DFT level will be used to validate the method and explain the theory behind the experiments. Results: The study of electronic spectra of the chelator, HQCC, reveals the appearance of a band at 262 nm along with a weak band at 335 nm due to π- π* and n- π* transitions respectively. Upon excitation with 335 nm, the ligand fluoresces at 388 nm wavelength. The intensity of the emission was affected in presence of metal ions, with maximum deviation for Fe(III). Selectivity studies showed that Fe(III) is more selective as compared to the biologically relevant metal ions viz., Al(III), Fe(III), Cr(III), Co(II), Fe(II), Ni(II), Zn(II), Cu(II), Mn(II) and Pb(II). pH dependent studies implied that the fluorescence intensity was highest at pH ~8.0, whereas maximum quenching for iron-HQCC system was observed at pH 7.4. The binding studies from the B-H plot confirms the formation of 1:1 complex with association constant of 5.95 × 106. The results obtained from experiments were in agreement with that obtained from the DFT and TD-DFT studies. Conclusion: A novel tripodal chelator based on 8-hydroxyquinoline and symmetric cyclohexane scaffold was successfully developed. In addition to the excellence of the ligand to be employed as a promising sensitive fluorescent probe for easy detection of Fe3+ions at the physiological pH with very low concentration (7.5 x 10-5 molL-1), the new ligand can be used as an OFF-ON-OFF pH sensor. Fe(III) encapsulation along with 1:1 ML-complexation formation have been established. Theoretical studies confirm a d-PET mechanism for the fluorescence quenching. DFT studies revealed that the neutral form of the ligand is less reactive than its protonated or the deprotonated form.

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