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Folic acid (FA) is an essential vitamin involved in crucial metabolic processes, while copper(II) ions play significant roles in various biological functions. This study aims to investigate the interaction between FA and Cu2+ using 1H and 13C NMR spectroscopy under different pH levels and concentrations. The research employed detailed NMR analysis to explore how Cu2+ binds to FA, focusing on changes in chemical shifts, diffusion coefficients, and copper-induced paramagnetic effects. The key findings reveal that Cu2+ predominantly coordinates with the pteridine ring (PTE) of FA, with minimal involvement from the glutamic acid (Glu) moiety. The interaction is strongly concentration-dependent: at lower FA concentrations, Cu2+ binds effectively to the PTE ring, while at higher concentrations, intermolecular interactions among FA molecules hinder copper binding. The study also observed pronounced paramagnetic effects on the PTE and p-aminobenzoic acid protons, with negligible effects on Glu signals. These results provide new insights into the structural characteristics of FA-Cu2+ complexes, contributing to a better understanding of their biochemical interactions and implications for folate metabolism. [ABSTRACT FROM AUTHOR]

This work focuses on the relationship between the coordination chemistry and antimicrobial activity of Zn (II) and Cu(II) complexes of histatin 5 and the products of its hydrolysis: its N-terminal fragment (histatin 5-8) and C-terminal fragment (histatin 8). Cu(II) coordinates in an albumin-like binding mode and Zn(II) binds to up to 3 His imidazoles. The antimicrobial activity of histatins and their metal complexes (i) strongly depends on pH - they are more active at pH 5.4 than at 7.4; (ii) the complexes and ligands alone are more effective in eradicating Gram-positive bacteria than the Gram-negative ones, and (iii) Zn(II) coordination is able to change the structure of the N-terminal region of histatin 5 (histatin 5-8) and moderately increase all of the studied histatins' antimicrobial potency. [ABSTRACT FROM AUTHOR]

Recently, we have studied the coordination chemistry of the Cu(II)–histidine-rich C-terminal tail (HRCT) complex of the mycobacterial GroEL1 protein. The structure of this domain differs significantly compared to the well-known methionine-glycine-rich GroEL chaperonin – it was predicted that mycobacterial GroEL1 could play a significant role in the metal homeostasis of Mycobacteria, especially copper. However, we found that this particular domain's pattern also repeats in a number of Ni(II)-binding proteins. Here, we present the studies concerning the properties of GroEL1 HRCT as a ligand for Ni(II) ions. For this purpose, we chose eight model peptides: L1 – Ac-DHDHHHGHAH, L2 – Ac-DKPAKAEDHDHHHGHAH, and 6 mutants of the latter in the pH range of 2–11. We examined the stoichiometry, stability, and spectroscopic features of copper complexes. We noticed that similar to the Cu(II)-complex, the presence of a Lys5 residue significantly increases the stability of the system. The impact of His mutations was also examined and carefully studied using NMR spectroscopy. His9 and His13 are the crucial residues for Ni(II) binding, whereas His12 has minimal relevance in complex formation. [ABSTRACT FROM AUTHOR]

Lycorine (LYC) is an active alkaloid first isolated from Narcissus pseudonarcissus and found in most Amaryllidaceae plants. It belongs to the same family as galantamine, which is the active component of a drug used for the treatment of Alzheimer's disease. Similarly to galantamine, LYC is able to suppress induced amyloid β (Aβ) toxicity in differentiated SH-SY5Y cell lines and it can weakly interact with the N-terminal region of Aβ via electrostatic interactions. The N-terminal Aβ domain is also involved in Cu(II)/Cu(I) binding and the formed complexes are known to play a key role in ROS production. In this study, the Aβ–LYC interaction in the absence and in the presence of copper ions was investigated by using the N-terminal Aβ peptide encompassing the first 16 residues. NMR analysis showed that Aβ can simultaneously interact with Cu(II) and LYC. The Cu(II) binding mode remains unchanged in the presence of LYC, while LYC association is favored when an Aβ–Cu(II) complex is formed. Moreover, UV-VIS studies revealed the ability of LYC to interfere with the catalytic activities of the Aβ–Cu(II) complexes by reducing the ascorbate consumption monitored at 265 nm. [ABSTRACT FROM AUTHOR]

The SH-SY5Y neuroblastoma cell line is often used as an in vitro model of neuronal function and is widely applied to study the molecular events leading to Alzheimer's disease (AD). Indeed, recently, basic research on SH-SY5Y cells has provided interesting insights for the discovery of new drugs and biomarkers for improved AD treatment and diagnosis. At the same time, untargeted NMR metabolomics is widely applied to metabolic profile analysis and screening for differential metabolites, to discover new biomarkers. In this paper, a compression technique based on convolutional autoencoders is proposed, which can perform a high dimensionality reduction in the spectral signal (up to more than 300 times), maintaining informative features (guaranteed by a reconstruction error always smaller than 5%). Moreover, before compression, an ad hoc preprocessing method was devised to remedy the scarcity of available data. The compressed spectral data were then used to train some SVM classifiers to distinguish diseased from healthy cells, achieving an accuracy close to 78%, a significantly better performance with respect to using standard PCA-compressed data. [ABSTRACT FROM AUTHOR]