Zinc and Cadmium Complexes of a Plant Metallothionein under Radical Stress: Desulfurisation Reactions Associated with the Formation oftrans-Lipids in Model Membranes

The complex salts CdL4(O3SCF3)2 (L = 2(1H)-pyridinethione (Py2SH), 4(1H)-pyridinethione (Py4SH), or 2(1H)-quinolinethione (Q2SH)) have been synthesized by the stoichiometric reaction of Cd(O3SCF3)2 and the appropriate thione. Both ambient-temperature 13C and reduced-temperature 111Cd NMR of CdL4(O3SCF3)2 in solution are consistent with L being bound through sulfur. Reduced-temperature NMR (31P, 77Se, 111Cd, as appropriate) of mixtures of CdL4(O3SCF3)2 and Cd(EPCy3)4(O3SCF3)2 (E = Se, Cy = c-C6H11) and of Cd(EPCy3)4(O3SCF3)2 (E = S, Se) and L in solution provides evidence for various [CdLn(EPCy3)4-n]2+. Similarly, reduced-temperature metal NMR of [CdL4]2+ and [CdL'4]2+ (L, L' = Py2SH, Py4SH, Q2SH; L not equal L') in solution shows the formation of [CdLnL'4-n]2+. Thus it has been demonstrated that at reduced temperature [CdL4]2+ is intact in solution and exchange of L is slow on the timescale of the metal chemical shift differences. From the NMR studies of Cd(EPCy3)4(O3SCF3)2 (E = S, Se):L mixtures, the binding preferences are found to be L > EPCy3 in solution. Similarly, from the reduced temperature metal NMR spectra of mixtures where L and L' compete for Cd(II) in solution, the binding preferences are Py4SH > Py2SH > Q2SH. The structure of Cd(Py2SH)4(NO3)2 (4) has been determined by single crystal X-ray analysis. Colorless crystals of 4 are tetragonal, I4(1)/acd with 8 molecules per unit cell of dimensions a = 18.660(3), c = 15.215(3) Å. The structure is comprised of recognizable NO3- anions and [Cd(Py2SH)4]2+ cations. In the cations, which have S4 symmetry, the ligands are S-bound. A network of NH···O hydrogen bonds links the cations and anions.Key words: aromatic heterocyclic thiones, cadmium complexes, phosphine chalcogenides, 111Cd, 31P, 77Se NMR, X-ray crystallography.

Download Full-text

Transport of heptafluorostearate across model membranes. Membrane transport of long-chain fatty acid anions I

The Journal of Lipid Research ◽

10.1016/s0022-2275(20)32386-5 ◽

2000 ◽

Vol 41 (5) ◽

pp. 775-787 ◽

Cited By ~ 1

Author(s):

W. Schmider ◽

A. Fahr ◽

H.E. Blum ◽

G. Kurz

Keyword(s):

Fatty Acid ◽

Membrane Transport ◽

Chain Fatty Acid ◽

Model Membranes ◽

Long Chain Fatty Acid ◽

Long Chain

Download Full-text

Tauroursodeoxycholic Acid (TUDCA)—Lipid Interactions and Antioxidant Properties of TUDCA Studied in Model of Photoreceptor Membranes

Membranes ◽

10.3390/membranes11050327 ◽

2021 ◽

Vol 11 (5) ◽

pp. 327

Author(s):

Michał J. Sabat ◽

Anna M. Wiśniewska-Becker ◽

Michał Markiewicz ◽

Katarzyna M. Marzec ◽

Jakub Dybas ◽

...

Keyword(s):

Antioxidant Activity ◽

Plasma Membranes ◽

Electron Paramagnetic Resonance Spectroscopy ◽

Protective Action ◽

Antioxidant Properties ◽

Model Membranes ◽

Dynamics Simulation ◽

Resonance Spectroscopy ◽

Paramagnetic Resonance ◽

Tauroursodeoxycholic Acid

Tauroursodeoxycholic acid (TUDCA), a hydrophilic bile acid containing taurine conjugated with the ursodeoxycholic acid (UDCA), has been known and used from ancient times as a therapeutic compound in traditional Chinese medicine. TUDCA has recently been gaining significant interest as a neuroprotective agent, also exploited in the visual disorders. Among several mechanisms of TUDCA’s protective action, its antioxidant activity and stabilizing effect on mitochondrial and plasma membranes are considered. In this work we investigated antioxidant activity of TUDCA and its impact on structural properties of model membranes of different composition using electron paramagnetic resonance spectroscopy and the spin labeling technique. Localization of TUDCA molecules in a pure POPC bilayer has been studied using a molecular dynamics simulation (MD). The obtained results indicate that TUDCA is not an efficient singlet oxygen (1O2 (1Δg)) quencher, and the determined rate constant of its interaction with 1O2 (1Δg) is only 1.9 × 105 M−1s−1. However, in lipid oxidation process induced by a Fenton reaction, TUDCA reveals substantial antioxidant activity significantly decreasing the rate of oxygen consumption in the system studied. In addition, TUDCA induces slight, but noticeable changes in the polarity and fluidity of the investigated model membranes. The results of performed MD simulation correspond very well with the experimental results.

Download Full-text

A peptide corresponding to an export-defective mutant OmpA signal sequence with asparagine in the hydrophobic core is unable to insert into model membranes

Journal of Biological Chemistry ◽

10.1016/s0021-9258(18)98699-0 ◽

1991 ◽

Vol 266 (22) ◽

pp. 14406-14412 ◽

Cited By ~ 1

Author(s):

D.W. Hoyt ◽

L.M. Gierasch

Keyword(s):

Signal Sequence ◽

Model Membranes ◽

Hydrophobic Core ◽

Defective Mutant

Download Full-text

In Vitro Evaluation of the Potential Pharmacological Activity and Molecular Targets of New Benzimidazole-Based Schiff Base Metal Complexes

Antibiotics ◽

10.3390/antibiotics10060728 ◽

2021 ◽

Vol 10 (6) ◽

pp. 728

Author(s):

Alberto Aragón-Muriel ◽

Yamil Liscano ◽

Yulieth Upegui ◽

Sara M. Robledo ◽

María Teresa Ramírez-Apan ◽

...

Keyword(s):

Schiff Base ◽

Molecular Docking ◽

Lanthanide Complexes ◽

Human Tumor ◽

Model Membranes ◽

Leishmania Braziliensis ◽

Cytotoxic Activities ◽

Schiff Base Ligands ◽

Major Interest

Metal-based drugs, including lanthanide complexes, have been extremely effective in clinical treatments against various diseases and have raised major interest in recent decades. Hence, in this work, a series of lanthanum (III) and cerium (III) complexes, including Schiff base ligands derived from (1H-benzimidazol-2-yl)aniline, salicylaldehyde, and 2,4-dihydroxybenzaldehyde were synthesized and characterized using different spectroscopic methods. Besides their cytotoxic activities, they were examined in human U-937 cells, primate kidney non-cancerous COS-7, and six other, different human tumor cell lines: U251, PC-3, K562, HCT-15, MCF-7, and SK-LU-1. In addition, the synthesized compounds were screened for in vitro antiparasitic activity against Leishmania braziliensis, Plasmodium falciparum, and Trypanosoma cruzi. Additionally, antibacterial activities were examined against two Gram-positive strains (S. aureus ATCC® 25923, L. monocytogenes ATCC® 19115) and two Gram-negative strains (E. coli ATCC® 25922, P. aeruginosa ATCC® 27583) using the microdilution method. The lanthanide complexes generally exhibited increased biological activity compared with the free Schiff base ligands. Interactions between the tested compounds and model membranes were examined using differential scanning calorimetry (DSC), and interactions with calf thymus DNA (CT-DNA) were investigated by ultraviolet (UV) absorption. Molecular docking studies were performed using leishmanin (1LML), cruzain (4PI3), P. falciparum alpha-tubulin (GenBank sequence CAA34101 [453 aa]), and S.aureus penicillin-binding protein 2a (PBP2A; 5M18) as the protein receptors. The results lead to the conclusion that the synthesized compounds exhibited a notable effect on model membranes imitating mammalian and bacterial membranes and rolled along DNA strands through groove interactions. Interactions between the compounds and studied receptors depended primarily on ligand structures in the molecular docking study.

Download Full-text