Copper Binding Research Articles

Copper and chromium binding by Pseudomonas aeruginosa strain PA01 for implications of heavy metal detoxification and soil remediation: A computational approach

Heavy metal pollution poses significant environmental and health risks due to the toxic effects of metals like copper and chromium at elevated concentrations. Despite their essential roles in trace amounts, these metals can be highly toxic. Bacteria such asPseudomonas aeruginosaare promising candidates for bioremediation due to their robustness and adaptability.The objective of this study was to analyze and identify potential copper and chromium binding genes involved in metal detoxification inPseudomonas aeruginosaPA01. The heavy metal binding protein identified as ferredoxin using MALDI-TOF/PMF-MS analysis was further characterized. The structure of the ferredoxin protein was elucidated using the SWISS-MODEL tool. Metal-binding domains were validated through a pattern search against UniProtKB/Swiss-Prot and UniProtKB/TrEMBL databases using the ScanProsite tool. Comparative sequence alignments were conducted between the copper-binding NosD gene ofP. aeruginosa, the ferredoxin gene ofP. aeruginosaPA01, and the chromium-binding iron hydrogenase 1 gene ofClostridium chromiireducens. The SWISS-MODEL analysis revealed alpha helices and beta sheets with key metal-coordinating amino acids (cysteine, glutamic acid, aspartic acid, histidine, and methionine). The ScanProsite tool confirmed the presence of a 4Fe-4S ferredoxin-type iron-sulphur binding domain essential for coordinating chromium and copper ions. Sequence alignments showed a 64.29 % similarity between the NosD gene and ferredoxin gene, and a 67 % identity between the iron hydrogenase 1 gene and ferredoxin gene, with correlations in amino acid residues involved in metal binding. These findings suggest that the ferredoxin gene could effectively bind heavy metal ions, offering potential applications in bioremediation of metal-polluted soils usingPseudomonasspecies. This study contributes to sustainable agricultural productivity by facilitating the targeted remediation of heavy metal-contaminated soils through biological means.

Copper homeostasis and neurodegenerative diseases.

Copper, one of the most prolific transition metals in the body, required for normal brain physiological activity and allows various functions to work normally through its range of concentrations. Copper homeostasis is meticulously maintained through a complex network of copper-dependent proteins, including copper transporters (CTR1 and CTR2), the two copper ion transporters the Cu -transporting ATPase 1 (ATP7A) and Cu-transporting beta (ATP7B), and the three copper chaperones ATOX1, CCS, and COX17. Disruptions in copper homeostasis can lead to either the deficiency or accumulation of copper in brain tissue. Emerging evidence suggests that abnormal copper metabolism or copper binding to various proteins, including ceruloplasmin and metallothionein, is involved in the pathogenesis of neurodegenerative disorders. However, the exact mechanisms underlying these processes are not known. Copper is a potent oxidant that increases reactive oxygen species production and promotes oxidative stress. Elevated reactive oxygen species levels may further compromise mitochondrial integrity and cause mitochondrial dysfunction. Reactive oxygen species serve as key signaling molecules in copper-induced neuroinflammation, with elevated levels activating several critical inflammatory pathways. Additionally, copper can bind aberrantly to several neuronal proteins, including alpha-synuclein, tau, superoxide dismutase 1, and huntingtin, thereby inducing neurotoxicity and ultimately cell death. This study focuses on the latest literature evaluating the role of copper in neurodegenerative diseases, with a particular focus on copper-containing metalloenzymes and copper-binding proteins in the regulation of copper homeostasis and their involvement in neurodegenerative disease pathogenesis. By synthesizing the current findings on the functions of copper in oxidative stress, neuroinflammation, mitochondrial dysfunction, and protein misfolding, we aim to elucidate the mechanisms by which copper contributes to a wide range of hereditary and neuronal disorders, such as Wilson's disease, Menkes' disease, Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, Huntington's disease, and multiple sclerosis. Potential clinically significant therapeutic targets, including superoxide dismutase 1, D-penicillamine (DPA), and 5,7-dichloro-2-[(dimethylamino)methyl]-8-hydroxyquinoline (PBT2), along with their associated therapeutic agents, are further discussed. Ultimately, we collate evidence that copper homeostasis may function in the underlying etiology of several neurodegenerative diseases and offer novel insights into the potential prevention and treatment of these diseases based on copper homeostasis.

Hemin, copper and amyloid-β: A medley involved in Alzheimer's disease. An interaction that fine regulates the reactivity

Metal ions have been shown to play a critical role in amyloid-β (Aβ) neurotoxicity and plaque formation which are key hallmarks of Alzheimer's disease. Amyloid-β peptides can bind both copper and hemin and this interaction modulates the redox chemistry of these metals. The characterization of the binding of hemin through UV–Vis spectroscopic titration with Aβ(4-16) shows a significantly higher affinity than that with Aβ(1-16). Also, the characterization of the hemin-catalyzed oxidation through different assays (peroxidase-like activity, ascorbate oxidation, HPLC-MS analysis of peptide oxidation) displays a greater reactivity in the presence of Aβ(4-16) when compared to that of Aβ(1-16). Since the Aβ(4-16) peptide sequence contains the typical amino-terminal copper and nickel binding motif (ATCUN), this leads to investigate the potential formation of ternary hemin/copper/Aβ(4-16) adducts. The evaluation of K1 and K2 (constants that regulate the formation of five-coordinated high-spin complex and of six-coordinated low-spin complex, respectively) for mixed systems indicates that the presence of copper stabilizes the 1:1 hemin-Aβ(4-16) species, partially hindering the formation of the low-spin complex. On the other hand, the formation of the ternary hemin/copper/Aβ(4-16) complex gives rise to a less efficient catalyst, resulting in a reduction of the overall oxidative reactivity. These results suggest that the reactivity of metal ions is finely modulated by the formation of complexes with amyloid peptides and this property is also regulated differently by the various in vivo relevant isoforms.

Zinc and copper effect mechanical cell adhesion properties of the amyloid precursor protein.

The amyloid precursor protein (APP) can be modulated by the binding of copper and zinc ions. Both ions bind with low nanomolar affinities to both subdomains (E1and E2) in the extracellular domain of APP. However, the impact of ion binding on structural and mechanical trans-dimerization properties is yet unclear. Using a bead aggregation assay (BAA), we found that zinc ions increase the dimerization of both subdomains, while copper promotes only dimerization of the E1 domain. In line with this, scanning force spectroscopy (SFS) analysis revealed an increase in APP adhesion force up to three-fold for copper and zinc. Interestingly, however, copper did not alter the separation length of APP dimers, whereas high zinc concentrations caused alterations in the structural features and a decrease of separation length. Together, our data provide clear differences in copper and zinc mediated APP trans-dimerization and indicate that zinc binding might favor a less flexible APP structure. This fact is of significant interest since changes in zinc and copper ion homeostasis are observed in Alzheimer's disease (AD) and were reported to affect synaptic plasticity. Thus, modulation of APP trans-dimerization by copper and zinc could contribute to early synaptic instability in AD.

Methionine-rich domains emerge as facilitators of copper recruitment in detoxification systems

Copper homeostasis mechanisms are critical for bacterial resistance to copper-induced stress. The Escherichia coli multicopper oxidase copper efflux oxidase (CueO) is part of the copper detoxification system in aerobic conditions. CueO contains a methionine-rich (Met-rich) domain believed to interact with copper, but its exact function and the importance of related copper-binding sites remain unclear. This study investigates these open questions by employing a multimodal and multiscale approach. Through the design of various E. coli CueO (EcCueO) variants with altered copper-coordinating residues and domain deletions, we employ biological, biochemical, and physico-chemical approaches to unravel in vitro CueO catalytic properties and in vivo copper resistance. Strong correlation between the different methods enables evaluation of EcCueO variants' activity as a function of Cu+ availability. Our findings demonstrate the Met-rich domain is not essential for cuprous oxidation, but it facilitates Cu+ recruitment from strongly chelated forms, acting as transient copper binding domain thanks to multiple methionines. They also indicate that the Cu6/7 copper-binding sites previously observed within the Met-rich domain play a negligible role. Meanwhile, Cu5, located at the interface with the Met-rich domain, emerges as the primary and sole substrate-binding active site for cuprous oxidation. The Cu5 coordination sphere strongly affects the enzyme activity and the in vivo copper resistance. This study provides insights into the nuanced role of CueO Met-rich domain, enabling the functions of copper-binding sites and the entire domain itself to be decoupled. This paves the way for a deeper understanding of Met-rich domains in the context of bacterial copper homeostasis.

Analytical Insights into Methods for Measuring Ischemia-Modified Albumin.

Ischemia-modified albumin (IMA) has emerged as a pivotal biomarker for the early detection of ischemic conditions, particularly myocardial ischemia, where timely diagnosis is crucial for effective intervention. This review provides an overview of the analytical methods for assessment of IMA, including Albumin Cobalt Binding (ACB), Albumin Copper Binding (ACuB), Enzyme-Linked Immunosorbent Assay (ELISA), new techniques such as liquid crystal biosensors (LCB), quantum dot coupled X-ray fluorescence spectroscopy (Q-XRF), mass spectrometry (MS), and electron paramagnetic resonance (EPR) spectroscopy. Each method was thoroughly examined for its analytical performance in terms of sensitivity, specificity, and feasibility. The ACB assay is the most readily implementable method in clinical laboratories for its cost-effectiveness and operational simplicity. On the other hand, the ACuB assay exhibits enhanced sensitivity and specificity, driven by the superior binding affinity of copper to IMA. Furthermore, nanoparticle-enhanced immunoassays and liquid crystal biosensors, while more resource-intensive, significantly improve the analytical sensitivity and specificity of IMA detection, enabling earlier and more accurate identification of ischemic events. Additionally, different biological matrices, such as serum, saliva, and urine, were reviewed to identify the most suitable for accurate measurements in clinical application. Although serum was considered the gold standard, non-invasive matrices such as saliva and urine are becoming increasingly feasible due to advances in technology. This review underscores the role of IMA in clinical diagnostics and suggests how advanced analytical techniques have the potential to significantly enhance patient outcomes in ischemic disease management.

The invisible hand of pre-adsorbates: Unveiling oxygen's role in sculpting Cu–TiN interfaces

Copper (Cu) binding to titanium nitride (TiN) surfaces is important for applications in catalysis, sensing, and electronics. However, achieving controlled and stable Cu attachment remains challenging. In this study, Density Functional Theory with Hubbard U corrections (DFT + U) is employed to investigate how pre-adsorbed oxygen (O) and sulfur (S) influence Cu attachment and the resulting interfacial properties. Contrary to initial expectations, our calculations reveal that the presence of pre-adsorbed O and S significantly weakens the Cu–TiN interface. Direct adsorption of Cu on the TiN surface, without pre-adsorbed species, results in a much higher adsorption energy (−13.94 eV), demonstrating stronger interfacial stability compared to systems with O (−2.06 eV) or S (−1.84 eV) pre-adsorption. Although pre-adsorbed O and S can modify the interface's electronic structure, the introduction of these species ultimately weakens the Cu–TiN interaction rather than enhancing it, as initially hypothesized. Analysis of the density of states (DOS) and charge transfer shows that direct Cu–TiN bonding maintains a more robust interaction, making it more suitable for applications requiring strong metal-ceramic interfaces. These findings highlight the critical role of surface chemistry in controlling the strength of Cu–TiN interfaces. The use of DFT + U calculations provides valuable insights into the bonding mechanisms and electronic changes at these interfaces, informing future design strategies for Cu–TiN systems with tailored properties for advanced technological applications.

Effect of Cu(II) and Conserved Copper Binding Sites onthe Multicopper Oxidase CopA and Characterization ofBioMnOx.

The microbial manganese removal process is believed to consist of the catalytic oxidation of Mn(II) by manganese oxidase. In this study, the multicopper oxidase CopA was purified and exhibited high manganese oxidation activity in vitro, and it was found that Cu(II) can significantly enhance its manganese oxidation activity. Gene site-directed mutagenesis was used to mutate four conserved copper binding sites of CopA to obtain four mutant strains. The manganese removal efficiencies of the four strains were determined, and it was found that H120 is the catalytically active site of CopA. The loss of Cu(II) and the mutation of the conserved copper binding site H120 resulted in the loss of ethoxyformyl and quinone modifications, a reduction in the number of modifications, and a change in the position of modifications, eventually causing a decrease in protein activity from 85.87% to 70.1%. These results reveal that Cu(II) and H120 play an indispensable role in manganese oxidation by the multicopper oxidase CopA. X-ray photoelectron spectroscopy (XPS) analysis indicates that biogenic manganese oxides produced by strains and by CopA were both composed of MnO2 and Mn3O4 and that the average valence of Mn was 3.2.

Streptomyces small laccase expressed in Aspergillus Niger as a new addition for the lignocellulose bioconversion toolbox

Laccases are multi-copper oxidases that are usually composed of three Cu-oxidase domains. Domains one and three house the copper binding sites, and the second domain is involved in forming a substrate-binding cleft. However, Streptomyces species are found to have small laccases (SLAC) that lack one of the three Cu-oxidase domains. This type of SLAC with interesting lignocellulose bioconversion activities has not been reported in Aspergillus niger. In our research, we explored the expression and engineering of the SLAC from Streptomyces leeuwenhoekii C34 in A. niger. Genes encoding two versions of the SLAC were expressed. One encoding the SLAC in its native form and a second encoding the SLAC fused to two N-terminal CBM1 domains. The latter is a configuration also known for specific yeast laccases. Both SLAC variants were functionally expressed in A. niger as shown by in vitro activity assays and proteome analysis. Laccase activity was also analyzed toward bioconversion of lignocellulosic rice straw. From this analysis it was clear that the SLAC activity improved the efficiency of saccharification of lignocellulosic biomass by cellulase enzyme cocktails.

Structure and dimerization properties of the plant-specific copper chaperone CCH

Copper chaperones of the ATX1 family are found in a wide range of organisms where these essential soluble carriers strictly control the transport of monovalent copper across the cytoplasm to various targets in diverse cellular compartments thereby preventing detrimental radical formation catalyzed by the free metal ion. Notably, the ATX1 family in plants contains two distinct forms of the cellular copper carrier. In addition to ATX1 having orthologs in other species, they also contain the copper chaperone CCH. The latter features an extra C-terminal extension whose function is still unknown. The secondary structure of this extension was predicted to be disordered in previous studies, although this has not been experimentally confirmed. Solution NMR studies on purified CCH presented in this study disclose that this region is intrinsically disordered regardless of the chaperone’s copper loading state. Further biophysical analyses of the purified metallochaperone provide evidence that the C-terminal extension stabilizes chaperone dimerization in the copper-free and copper-bound states. A variant of CCH lacking the C-terminal extension, termed CCHΔ, shows weaker dimerization but similar copper binding. Computational studies further corroborate the stabilizing role of the C-terminal extension in chaperone dimerization and identify key residues that are vital to maintaining dimer stability.

A cuproptosis-related prognostic signature for guiding clinical diagnosis and treatment in uveal melanoma patients

BackgroundCuproptosis, one of the most recently discovered forms of cell death, is induced by the disruption of copper binding to the mitochondrial respiratory acylation components. However, the mechanism underlying cuproptosis in uveal melanoma (UM) has not yet been adequately studied. MethodsRNA and clinical data were obtained from The Cancer Genome Atlas (TCGA) database. Differentially expressed cuproptosis-related genes were identified by R software. A prognostic signature was constructed by applying LASSO regression and Cox regression models. The associations between the signature and the immune microenvironment, overall survival, and drug sensitivity were studied. In addition, qPCR and Western blotting were performed on UM cells and RPE cell lines to verify the expression levels of the genes encoding dihydrolipoamide dehydrogenase (DLD) and dihydrolipoamide S-succinyltransferase (DLST) in UM cases. ResultsUsing a cuproptosis-related prognostic signature, UM samples were classified into high- and low-risk groups. A significant difference in overall survival between the two risk groups was evident. Receiver operating characteristic curves demonstrated that the signature is a reliable predictor of prognosis. Immune cell infiltration, drug sensitivity, and immune checkpoint expression were analysed. Significant immune difference between the two high-risk groups was found, and the high expression of immune checkpoints in high-risk groups suggests significant immunotherapy potential. In addition, drug sensitivity analysis experiments suggest that erlotinib may be a potential treatment for high-risk patients. The results of in vitro experiments confirmed that DLD and DLST had higher expression levels in UM cell lines. ConclusionsThe prognostic signature developed in this study is a reliable biomarker for predicting the prognosis of UM and may serve as a tool for personalised treatment of patients with UM.

A Water-Soluble Multifunctional Probe for Colorimetric Copper Sensing, Lysosome Labelling and Live-Cell Imaging.

We report a water-soluble fluorescence and colorimetric copper probe (LysoBC1); this system can also serve for lysosome labeling and for the dynamic tracking of Cu2+ in living cells. The sensing mechanism takes advantage of the synergic action by the following three components: i) a lysosome targeting unit, ii) the spirolactam ring-opening for the selective copper chelation and iii) the metal-mediated hydrolysis of the rhodamine moiety for fluorescence enhancement. In aqueous environment the molecule acts as a fluorescent reversible pH sensor and as colorimetric probe for Cu2+ at physiological pH; the hydrolysis of the copper targeting unit resulted in a 50-fold increase of the fluorescence intensity. Most importantly, in vitro cell analyses in undifferentiated (SH SY5Y) and differentiated (d-SH SY5Y) neuroblastoma cells, LysoBC1 is able to selectively accumulate into lysosome while the copper binding ability allowed us to monitor intracellular copper accumulation into lysosome.

The Role of Glia in Wilson's Disease: Clinical, Neuroimaging, Neuropathological and Molecular Perspectives.

Wilson's disease (WD) is inherited in an autosomal recessive manner and is caused by pathogenic variants of the ATP7B gene, which are responsible for impaired copper transport in the cell, inhibition of copper binding to apoceruloplasmin, and biliary excretion. This leads to the accumulation of copper in the tissues. Copper accumulation in the CNS leads to the neurological and psychiatric symptoms of WD. Abnormalities of copper metabolism in WD are associated with impaired iron metabolism. Both of these elements are redox active and may contribute to neuropathology. It has long been assumed that among parenchymal cells, astrocytes have the greatest impact on copper and iron homeostasis in the brain. Capillary endothelial cells are separated from the neuropil by astrocyte terminal legs, putting astrocytes in an ideal position to regulate the transport of iron and copper to other brain cells and protect them if metals breach the blood-brain barrier. Astrocytes are responsible for, among other things, maintaining extracellular ion homeostasis, modulating synaptic transmission and plasticity, obtaining metabolites, and protecting the brain against oxidative stress and toxins. However, excess copper and/or iron causes an increase in the number of astrocytes and their morphological changes observed in neuropathological studies, as well as a loss of the copper/iron storage function leading to macromolecule peroxidation and neuronal loss through apoptosis, autophagy, or cuproptosis/ferroptosis. The molecular mechanisms explaining the possible role of glia in copper- and iron-induced neurodegeneration in WD are largely understood from studies of neuropathology in Parkinson's disease and Alzheimer's disease. Understanding the mechanisms of glial involvement in neuroprotection/neurotoxicity is important for explaining the pathomechanisms of neuronal death in WD and, in the future, perhaps for developing more effective diagnostic/treatment methods.

Leptochelins A-C, Cytotoxic Metallophores Produced by Geographically Dispersed Leptothoe Strains of Marine Cyanobacteria.

Metals are important cofactors in the metabolic processes of cyanobacteria, including photosynthesis, cellular respiration, DNA replication, and the biosynthesis of primary and secondary metabolites. In adaptation to the marine environment, cyanobacteria use metallophores to acquire trace metals when necessary as well as to reduce potential toxicity from excessive metal concentrations. Leptochelins A-C were identified as structurally novel metallophores from three geographically dispersed cyanobacteria of the genus Leptothoe. Determination of the complex structures of these metabolites presented numerous challenges, but they were ultimately solved using integrated data from NMR, mass spectrometry and deductions from the biosynthetic gene cluster. The leptochelins are comprised of halogenated linear NRPS-PKS hybrid products with multiple heterocycles that have potential for hexadentate and tetradentate coordination with metal ions. The genomes of the three leptochelin producers were sequenced, and retrobiosynthetic analysis revealed one candidate biosynthetic gene cluster (BGC) consistent with the structure of leptochelin. The putative BGC is highly homologous in all three Leptothoe strains, and all possess genetic signatures associated with metallophores. Postcolumn infusion of metals using an LC-MS metabolomics workflow performed with leptochelins A and B revealed promiscuous binding of iron, copper, cobalt, and zinc, with greatest preference for copper. Iron depletion and copper toxicity experiments support the hypothesis that leptochelin metallophores may play key ecological roles in iron acquisition and in copper detoxification. In addition, the leptochelins possess significant cytotoxicity against several cancer cell lines.

Copper Distribution and Binding Affinity to Size-Fractioned Dissolved and Particulate Organic Matter in River Sediment

This study investigated the distribution of copper in sediment dissolved and particulate organic matter (DOM and POM) based on their size. The DOM and alkaline extracted POM (AEOM) were separated into five size fractions using a cross-flow ultrafiltration (CFUF) system. The results showed that Cu mass was mainly distributed in the low molecular weight (<1 kDa, LMW) fraction of the DOM with an average range of 78.1–83.1%. Conversely, the high molecular weight (1 kDa–0.45 μm, HMW) AEOM fraction had a higher distribution of Cu mass with an average range of 92.6–93.3%. The Cu and AEOM binding affinity ratios (CuBAAEOM) ranged from 17.0 to 149.6 μmol/g-C in site-1 and from 20.6 to 143.7 μmol/g-C in site-2. The HMW CuBAAEOM ratios were significantly higher than the LMW ratios. The Cu and DOM binding affinity ratios (CuBADOM) ranged from 5.6 to 358.6 μmol/g-C and 17.2 to 126.6 μmol/g-C in site-1 and site-2, respectively. However, the LMW CuBADOM ratios were significantly higher than the HMW ratios. Optical indices suggested that the AEOM had more aromaticity and terrestrial and allochthonous contributions than the DOM. The optical indices were significantly correlated with the CuBAAEOM ratios but weakly correlated with the CuBADOM ratios. Sediment exchange between POM and DOM may affect copper distribution. DOM has a low-molecular-weight composition, while POM retains high-molecular-weight organic matter.

Integrated Experimental and Theoretical Investigation of Copper Active Site Properties of a Lytic Polysaccharide Monooxygenase from Serratia marcescens.

In this paper, we employed a multidisciplinary approach, combining experimental techniques and density functional theory (DFT) calculations to elucidate key features of the copper coordination environment of the bacterial lytic polysaccharide monooxygenase (LPMO) from Serratia marcescens (SmAA10). The structure of the holo-enzyme was successfully obtained by X-ray crystallography. We then determined the copper(II) binding affinity using competing ligands and observed that the affinity of the histidine brace ligands for copper is significantly higher than previously described. UV-vis, advanced electron paramagnetic resonance (EPR), and X-ray absorption spectroscopy (XAS) techniques, including high-energy resolution fluorescence detected (HERFD) XAS, were further used to gain insight into the copper environment in both the Cu(II) and Cu(I) redox states. The experimental data were successfully rationalized by DFT models, offering valuable information on the electronic structure and coordination geometry of the copper center. Finally, the Cu(II)/Cu(I) redox potential was determined using two different methods at ca. 350 mV vs NHE and rationalized by DFT calculations. This integrated approach not only advances our knowledge of the active site properties of SmAA10 but also establishes a robust framework for future studies of similar enzymatic systems.

Purification, characterization and three-dimensional structure prediction of multicopper oxidase Laccases from Trichoderma lixii FLU1 and Talaromyces pinophilus FLU12

Broad-spectrum biocatalysts enzymes, Laccases, have been implicated in the complete degradation of harmful pollutants into less-toxic compounds. In this study, two extracellularly produced Laccases were purified to homogeneity from two different Ascomycetes spp. Trichoderma lixii FLU1 (TlFLU1) and Talaromyces pinophilus FLU12 (TpFLU12). The purified enzymes are monomeric units, with a molecular mass of 44 kDa and 68.7 kDa for TlFLU1 and TpFLU12, respectively, on SDS-PAGE and zymogram. It reveals distinct properties beyond classic protein absorption at 270–280 nm, with TlFLU1's peak at 270 nm aligning with this typical range of type II Cu site (white Laccase), while TpFLU12's unique 600 nm peak signifies a type I Cu2+ site (blue Laccase), highlighting the diverse spectral fingerprints within the Laccase family. The Km and kcat values revealed that ABTS is the most suitable substrate as compared to 2,6-dimethoxyphenol, caffeic acid and guaiacol for both Laccases. The bioinformatics analysis revealed critical His, Ile, and Arg residues for copper binding at active sites, deviating from the traditional two His and a Cys motif in some Laccases. The predicted biological functions of the Laccases include oxidation–reduction, lignin metabolism, cellular metal ion homeostasis, phenylpropanoid catabolism, aromatic compound metabolism, cellulose metabolism, and biological adhesion. Additionally, investigation of degradation of polycyclic aromatic hydrocarbons (PAHs) by purified Laccases show significant reductions in residual concentrations of fluoranthene and anthracene after a 96-h incubation period. TlFLU1 Laccase achieved 39.0% and 44.9% transformation of fluoranthene and anthracene, respectively, while TpFLU12 Laccase achieved 47.2% and 50.0% transformation, respectively. The enzyme structure–function relationship study provided insights into the catalytic mechanism of these Laccases for possible biotechnological and industrial applications.

Mechanisms of cuproptosis and its relevance to distinct diseases.

Copper is a trace element required by the organism, but once the level of copper exceeds the threshold, it becomes toxic and even causes death. The underlying mechanisms of copper-induced death are inconclusive, with different studies showing different opinions on the mechanism of copper-induced death. Multiple investigations have shown that copper induces oxidative stress, endoplasmic reticulum stress, nucleolar stress, and proteasome inhibition, all of which can result in cell death. The latest research elucidates a copper-dependent death and denominates it as cuproptosis. Cuproptosis takes place through the combination of copper and lipoylated proteins of the tricarboxylic acid cycle, triggering agglomeration of lipoylated proteins and loss of iron-sulfur cluster proteins, leading to proteotoxic stress and ultimately death. Given the toxicity and necessity of copper, abnormal levels of copper lead to diseases such as neurological diseases and cancer. The development of cancer has a high demand for copper, neurological diseases involve the change of copper contents and the binding of copper to proteins. There is a close relationship between these two kinds of diseases and copper. Here, we summarize the mechanisms of copper-related death, and the association between copper and diseases, to better figure out the influence of copper in cell death and diseases, thus advancing the clinical remedy of these diseases.

Primary Nucleation of Polymorphic α-Synuclein Dimers Depends on Copper Concentrations and Definite Copper-Binding Site.

The primary nucleation process of α-synuclein (AS) that forms toxic oligomeric species is the early stage of the pathological cause of Parkinson's disease. It is well-known that copper influences this primary nucleation process. While significant efforts have been made to solve the structures of polymorphic AS fibrils, the structures of AS oligomers and the copper-bound AS oligomers at the molecular level and the effect of copper concentrations on the primary nucleation are elusive. Here, we propose and demonstrate new molecular mechanism pathways of primary nucleation of AS that are tuned by distinct copper concentrations and by a specific copper-binding site. We present the polymorphic AS dimers bound to different copper-binding sites at the atomic resolution in high- and low-copper concentrations, using extensive molecular dynamics simulations. Our results show the complexity of the primary nucleation pathways that rely on the copper concentrations and the copper binding site. From a broader perspective, our study proposes a new strategy to control the primary nucleation of other toxic amyloid oligomers in other neurodegenerative diseases.

Cuproptosis in lung cancer: therapeutic options and prognostic models.

Lung cancer (LC) is a serious threat to mankind. The survival of LC patients is still poor despite the enormous efforts that have been made to develop novel treatments. A copper-dependent cell death termed cuproptosis is distinct from known programmed cell death (PCD). Cuproptosis is induced by the disruption of the binding of copper to lipoylated tricarboxylic acid (TCA) cycle proteins of mitochondrial respiratory chains. Potential approaches for treating LC are inducing cell cuproptosis and targeting cell copper death mechanisms. Thus, in this review, we summarize the systemic and cellular metabolic processes of copper. We highlight the possible therapeutic options of employing copper ionophores and chelators for inducing cuproptosis. Moreover, we summarize the prognostic models based on cuproptosis-related genes (CRGs) to identify promising biomarkers for tumor diagnosis and therapy. This review aims to provide a comprehensive summary of CRGs-based prognostic models and promising therapeutic options for cuproptosis induction in LC.