The Impact of ZIP8 Disease-Associated Variants G38R, C113S, G204C, and S335T on Selenium and Cadmium Accumulations: The First Characterization

The metal cation symporter ZIP8 (SLC39A8) is a transmembrane protein that imports the essential micronutrients iron, manganese, and zinc, as well as heavy toxic metal cadmium (Cd). It has been recently suggested that selenium (Se), another essential micronutrient that has long been known for its role in human health and cancer risk, may also be transported by the ZIP8 protein. Several mutations in the ZIP8 gene are associated with the aberrant ion homeostasis of cells and can lead to human diseases. However, the intricate relationships between ZIP8 mutations, cellular Se homeostasis, and human diseases (including cancers and illnesses associated with Cd exposure) have not been explored. To further verify if ZIP8 is involved in cellular Se transportation, we first knockout (KO) the endogenous expression of ZIP8 in the HeLa cells using the CRISPR/Cas9 system. The elimination of ZIP8 expression was examined by PCR, DNA sequencing, immunoblot, and immunofluorescence analyses. Inductively coupled plasma mass spectrometry indicated that reduced uptake of Se, along with other micronutrients and Cd, was observed in the ZIP8-KO cells. In contrast, when ZIP8 was overexpressed, increased Se uptake could be detected in the ZIP8-overexpressing cells. Additionally, we found that ZIP8 with disease-associated single-point mutations G38R, G204C, and S335T, but not C113S, showed reduced Se transport ability. We then evaluated the potential of Se on Cd cytotoxicity prevention and therapy of cancers. Results indicated that Se could suppress Cd-induced cytotoxicity via decreasing the intracellular Cd transported by ZIP8, and Se exhibited excellent anticancer activity against not all but only selected cancer cell lines, under restricted experimental conditions. Moreover, clinical-based bioinformatic analyses revealed that up-regulated ZIP8 gene expression was common across multiple cancer types, and selenoproteins that were significantly co-expressed with ZIP8 in these cancers had been identified. Taken together, this study concludes that ZIP8 is an important protein in modulating cellular Se levels and provides insights into the roles of ZIP8 and Se in disease prevention and therapy.

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Investigating the interaction between Organic Anion Transporter 1 and Ochratoxin A: an in silico structural study to depict early molecular events of substrate recruitment and the impact of single point mutations

Toxicology Letters ◽

10.1016/j.toxlet.2021.11.001 ◽

2021 ◽

Author(s):

Jochem Louisse ◽

Jean Lou C.M Dorne ◽

Luca Dellafiora

Keyword(s):

Ochratoxin A ◽

In Silico ◽

Organic Anion ◽

Single Point ◽

Point Mutations ◽

Organic Anion Transporter ◽

Anion Transporter ◽

Molecular Events ◽

Single Point Mutations ◽

The Impact

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Assessing Protein-Drug Resistance Due to Mutations via a Rigidity Analysis in silico Approach

10.29007/7gnf ◽

2020 ◽

Author(s):

Dylan Carpenter ◽

Tess Thackray ◽

Cecilia Kalthoff ◽

Filip Jagodzinski

Keyword(s):

Drug Resistance ◽

Amino Acid ◽

In Silico ◽

Single Point ◽

Point Mutations ◽

Single Point Mutation ◽

Protein Drug ◽

Ligand Complex ◽

Rigidity Analysis ◽

The Impact

A mutation to the amino acid sequence of a protein can cause a biomolecule to be resistant to the intended effects of a drug. Assessing the changes of a drug’s efficacy in response to mutations via mutagenesis wet-lab experiments is prohibitively time consuming for even a single point mutation, let alone for all possible mutations. Existing approaches for inferring mutation-induced drug resistance are available, but all of them reason about mutations of residues at or very near the protein-drug interface. However, there are examples of mutations far away from the region where the ligand binds, but which nonetheless render a protein resistant to the effects of the drug. We present a proof-of-concept computational pipeline that generates in silico the set of all possible single point mutations in a protein-ligand complex. We assess drug resistance using a graph theoretic rigidity analysis approach. Unlike existing methods, we are able to assess the impact of mutations far away from the protein-drug interface. We introduce several visualizations for exploring how amino acid substitutions both near and far away from where the ligand interacts with a protein target have a stabilizing or destabilizing effect on the protein-drug complex. We discuss our analytical approach in the context of experimental data from the literature about clinically known protein-drug interactions.

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HIV recombination: what is the impact on antiretroviral therapy?

Journal of The Royal Society Interface ◽

10.1098/rsif.2005.0064 ◽

2005 ◽

Vol 2 (5) ◽

pp. 489-503 ◽

Cited By ~ 50

Author(s):

Christophe Fraser

Keyword(s):

Antiretroviral Therapy ◽

Single Point ◽

Point Mutations ◽

Wild Type Virus ◽

Wild Type ◽

Genetic Barrier ◽

Resistant Strains ◽

Single Point Mutations ◽

The Impact ◽

Retroviral Recombination

Retroviral recombination is a potential mechanism for the development of multiply drug resistant viral strains but the impact on the clinical outcomes of antiretroviral therapy in HIV-infected patients is unclear. Recombination can favour resistance by combining single-point mutations into a multiply resistant genome but can also hinder resistance by breaking up associations between mutations. Previous analyses, based on population genetic models, have suggested that whether recombination is favoured or hindered depends on the fitness interactions between loci, or epistasis. In this paper, a mathematical model is developed that includes viral dynamics during therapy and shows that population dynamics interact non-trivially with population genetics. The outcome of therapy depends critically on the changes to the frequency of cell co-infection and I review the evidence available. Where recombination does have an effect on therapy, it is always to slow or even halt the emergence of multiply resistant strains. I also find that for patients newly infected with multiply resistant strains, recombination can act to prevent reversion to wild-type virus. The analysis suggests that treatment targeted at multiple parts of the viral life-cycle may be less prone to drug resistance due to the genetic barrier caused by recombination but that, once selected, mutants resistant to such regimens may be better able to persist in the population.

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Combination of mitochondrial tRNA and OXPHOS mutation reduces lifespan and physical condition in aged mice

10.1101/233593 ◽

2017 ◽

Cited By ~ 1

Author(s):

G. Reichart ◽

J. Mayer ◽

T. Tokay ◽

F. Lange ◽

C. Johne ◽

...

Keyword(s):

Complex Traits ◽

Single Point ◽

Point Mutations ◽

Complex Iv ◽

Mtdna Mutations ◽

Tissue Integrity ◽

Mitochondrial Superoxide ◽

Oxphos Complex ◽

Single Point Mutations ◽

The Impact

AbstractMutations in the mitochondrial DNA (mtDNA) are widely known to impact on lifespan and tissue integrity. For example, more than 250 pathogenic mtDNA mutations are known, many of which lead to neurological symptoms. In addition, major neurodegenerative diseases share key components of their etiopathogenesis with regard to mtDNA mutations, mitochondrial dysfunction and oxidative stress. In our study we used a set of conplastic mouse models carrying stable point mutations in mitochondrial genes of transfer RNA (tRNA) and oxidative phosphorylation (OXPHOS)-proteins. We analyzed the impact of these mutations on complex traits like lifespan, learning and memory in the ageing process. The combination of both point mutations in the OXPHOS complex IV gene and adenine insertions in the mitochondrially encoded tRNA arginine (tRNA-Arg) gene (mt-Tr) leads to an age-dependent phenotype with elevated mitochondrial superoxide production in the neocortex. Mice with this combination of tRNA and OXPHOS mutations show significantly reduced lifespan and poor physical constitution at the age of 24 months, whereas single point mutations in OXPHOS or mt-tRNA(Arg) do not have this impact. Therefore, we suggest a synergistic effect of these mutations.

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Impact of Specific pbp5 Mutations on Expression of β-Lactam Resistance in Enterococcus faecium

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.48.8.3028-3032.2004 ◽

2004 ◽

Vol 48 (8) ◽

pp. 3028-3032 ◽

Cited By ~ 84

Author(s):

Louis B. Rice ◽

Samuel Bellais ◽

Lenore L. Carias ◽

Rebecca Hutton-Thomas ◽

Robert A. Bonomo ◽

...

Keyword(s):

Active Site ◽

Enterococcus Faecium ◽

Single Point ◽

Point Mutations ◽

Outer Edge ◽

Ampicillin Resistance ◽

Clinical Strains ◽

Close Proximity ◽

Single Point Mutations ◽

The Impact

ABSTRACT We tested the impact of individual PBP 5 mutations on expression of ampicillin resistance in Enterococcus faecium using a shuttle plasmid designed to facilitate expression of cloned pbp5 in ampicillin-susceptible E. faecium D344SRF. Substitutions that had been implicated in contributing to the resistance of clinical strains conferred only modest levels of resistance when they were present as single point mutations. The levels of resistance were amplified when some mutations were present in combination. In particular, a methionine-to-alanine change at position 485 (in close proximity to the active site) combined with the insertion of a serine at position 466 (located in a loop that forms the outer edge of the active site) was associated with the highest levels of resistance to all β-lactams. Affinity for penicillin generally correlated with β-lactam MICs for the mutants, but these associations were not strictly proportional.

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Predicting the impact of deleterious single point mutations in SMAD gene family using structural bioinformatics approach

Interdisciplinary Sciences Computational Life Sciences ◽

10.1007/s12539-012-0122-0 ◽

2012 ◽

Vol 4 (2) ◽

pp. 103-115 ◽

Cited By ~ 4

Author(s):

C. George Priya Doss ◽

N. Nagasundaram ◽

Himani Tanwar

Keyword(s):

Gene Family ◽

Single Point ◽

Point Mutations ◽

Structural Bioinformatics ◽

Single Point Mutations ◽

The Impact

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Cupin Variants as Macromolecular Ligand Library for Stereoselective Michael Addition of Nitroalkanes

10.26434/chemrxiv.11481834.v1 ◽

2019 ◽

Author(s):

Nobutaka Fujieda ◽

Miho Yuasa ◽

Yosuke Nishikawa ◽

Genji Kurisu ◽

Shinobu Itoh ◽

...

Keyword(s):

Michael Addition ◽

In Silico ◽

Addition Reaction ◽

Single Point ◽

Point Mutations ◽

Unsaturated Ketone ◽

Michael Addition Reaction ◽

Beta Barrel ◽

Cupin Superfamily ◽

Single Point Mutations

Cupin superfamily proteins (TM1459) work as a macromolecular ligand framework with a double-stranded beta-barrel structure ligating to a Cu ion through histidine side chains. Variegating the first coordination sphere of TM1459 revealed that H52A and H54A/H58A mutants effectively catalyzed the diastereo- and enantio-selective Michael addition reaction of nitroalkanes to an α,β-unsaturated ketone. Moreover, in silico substrate docking signified C106N and F104W single-point mutations, which inverted the diastereoselectivity of H52A and further improved the stereoselectivity of H54A/H58A, respectively.

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The Impact of Bioconjugation on the Interfacial Activity of a Protein Biosurfactant

10.26434/chemrxiv.7497053.v1 ◽

2018 ◽

Author(s):

Hossam H Tayeb ◽

Marina Stienecker ◽

Anton Middelberg ◽

Frank Sainsbury

Keyword(s):

Polyethylene Glycol ◽

Colloidal Stability ◽

Point Mutations ◽

Pharmaceutical Formulations ◽

Industrial Processes ◽

Parent Molecule ◽

Site Specific ◽

Interfacial Activity ◽

Surface Active ◽

The Impact

Biosurfactants, are surface active molecules that can be produced by renewable, industrially scalable biologic processes. DAMP4, a designer biosurfactant, enables the modification of interfaces via genetic or chemical fusion to functional moieties. However, bioconjugation of addressable amines introduces heterogeneity that limits the precision of functionalization as well as the resolution of interfacial characterization. Here we designed DAMP4 variants with cysteine point mutations to allow for site-specific bioconjugation. The DAMP4 variants were shown to retain the structural stability and interfacial activity characteristic of the parent molecule, while permitting efficient and specific conjugation of polyethylene glycol (PEG). PEGylation results in a considerable reduction on the interfacial activity of both single and double mutants. Comparison of conjugates with one or two conjugation sites shows that both the number of conjugates as well as the mass of conjugated material impacts the interfacial activity of DAMP4. As a result, the ability of DAMP4 variants with multiple PEG conjugates to impart colloidal stability on peptide-stabilized emulsions is reduced. We suggest that this is due to constraints on the structure of amphiphilic helices at the interface. Specific and efficient bioconjugation permits the exploration and investigation of the interfacial properties of designer protein biosurfactants with molecular precision. Our findings should therefore inform the design and modification of biosurfactants for their increasing use in industrial processes, and nutritional and pharmaceutical formulations.

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