Human feline leukaemia virus subgroup C receptor-related proteins 1 and 2 (FLVCR1 and FLVCR2) are members of the major facilitator superfamily. Their dysfunction is linked to several clinical disorders, including PCARP, HSAN and Fowler syndrome. Earlier studies concluded that FLVCR1 may function as a haem exporter, whereas FLVCR2 was suggested to act as a haem importer, yet conclusive biochemical and detailed molecular evidence remained elusive for the function of both transporters.
View Article and Find Full Text PDFIron-bound cyclic tetrapyrroles (hemes) are redox-active cofactors in bioenergetic enzymes. However, the mechanisms of heme transport and insertion into respiratory chain complexes remain unclear. Here, we used cellular, biochemical, structural and computational methods to characterize the structure and function of the heterodimeric bacterial ABC transporter CydDC.
View Article and Find Full Text PDFCytochromes are essential for microaerobic respiration of many prokaryotes including a number of human pathogens. These enzymes catalyze the reduction of molecular oxygen to water using quinols as electron donors. Their importance for prokaryotic survival and the absence of eukaryotic homologs make these enzyme ideal targets for antimicrobial drugs.
View Article and Find Full Text PDFCytochrome bd-type oxidases play a crucial role for survival of pathogenic bacteria during infection and proliferation. This role and the fact that there are no homologues in the mitochondrial respiratory chain qualify cytochrome bd as a potential antimicrobial target. However, few bd oxidase selective inhibitors have been described so far.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
December 2021
The treatment of infectious diseases caused by multidrug-resistant pathogens is a major clinical challenge of the 21st century. The membrane-embedded respiratory cytochrome -type oxygen reductase is a critical survival factor utilized by pathogenic bacteria during infection, proliferation and the transition from acute to chronic states. encodes for two cytochrome isoforms that are both involved in respiration under oxygen limited conditions.
View Article and Find Full Text PDFCytochrome c oxidases are among the most important and fundamental enzymes of life. Integrated into membranes they use four electrons from cytochrome c molecules to reduce molecular oxygen (dioxygen) to water. Their catalytic cycle has been considered to start with the oxidized form.
View Article and Find Full Text PDFMultidrug and toxic compound extrusion (MATE) transporters are widespread in all domains of life. Bacterial MATE transporters confer multidrug resistance by utilizing an electrochemical gradient of H or Na to export xenobiotics across the membrane. Despite the availability of X-ray structures of several MATE transporters, a detailed understanding of the transport mechanism has remained elusive.
View Article and Find Full Text PDFUsing biocompatible polymer nanofibrous conduits with a controlled drug delivery have attracted much attention for peripheral nerve regeneration. This work was aimed at preparing electrospun poly (l-lactide-co-D, l-lactide) (PLDLLA) containing multi-walled carbon nanotubes (MWCNTs) and 4-aminopyridine (4-AP)-loaded molecularly imprinted nanoparticles (MIP) as well as evaluating their performance in in vitro and in vivo assessments. After synthesis of MIP based on poly (methacrylic acid) with imprinting factor of 1.
View Article and Find Full Text PDFNew drugs are urgently needed to combat the global TB epidemic. Targeting simultaneously multiple respiratory enzyme complexes of Mycobacterium tuberculosis is regarded as one of the most effective treatment options to shorten drug administration regimes, and reduce the opportunity for the emergence of drug resistance. During infection and proliferation, the cytochrome bd oxidase plays a crucial role for mycobacterial pathophysiology by maintaining aerobic respiration at limited oxygen concentrations.
View Article and Find Full Text PDFCytochrome bd oxidase is a bacterial terminal oxygen reductase that was suggested to enable adaptation to different environments and to confer resistance to stress conditions. An electrocatalytic study of the cyt bd oxidases from Escherichia coli, Corynebacterium glutamicum and Geobacillus thermodenitrificans gives evidence for a different reactivity towards oxygen. An inversion of the redox potential values of the three hemes is found when comparing the enzymes from different bacteria.
View Article and Find Full Text PDFSeveral types of nanocarriers, most of which show significant cytotoxicity, have been developed to overcome the problem of gene-delivery barriers. Biocompatibility, low toxicity and water solubility of carbon nanodots (CNDs) are major advantages that recommend them as delivery systems. We present a simple method to produce positively charged CNDs.
View Article and Find Full Text PDFCortisol is a steroid hormone that regulates a wide range of vital processes. Its level changes with diurnal rhythm and reacts to stress. Measurement of cortisol levels is still a complex multi-step process.
View Article and Find Full Text PDFCisplatin treatment confers the relative resistance to MCF-7 cells as compared to other breast cancer cell lines. One principal reason is that chemotherapeutic agents induce autophagy in these cells to inhibit apoptosis. Binding immunoglobulin protein (BiP), a master regulator of unfolded protein response (UPR) and 14-3-3ζ are two critical proteins upregulated in breast cancer rendering resistance to anticancer drugs.
View Article and Find Full Text PDFThe outer membrane of Gram-negative bacteria acts as an initial diffusion barrier that shields the cell from the environment. It contains many membrane-embedded proteins required for functionality of this system. These proteins serve as solute and lipid transporters or as machines for membrane insertion or secretion of proteins.
View Article and Find Full Text PDFThis dataset includes 1032 runs from a biomass downdraft gasifier integrated with power production unit that is fed by 86 different types of biomasses from different groups (e.g. wood and woody biomasses, herbaceous and agricultural biomasses, animal biomasses, mixed biomasses and contaminated biomasses) and under various operating conditions.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
September 2020
Heteromeric amino acid transporters (HATs) comprise a group of membrane proteins that belong to the solute carrier (SLC) superfamily. They are formed by two different protein components: a light chain subunit from an SLC7 family member and a heavy chain subunit from the SLC3 family. The light chain constitutes the transport subunit whereas the heavy chain mediates trafficking to the plasma membrane and maturation of the functional complex.
View Article and Find Full Text PDFThe respiratory chain of Escherichia coli contains two different types of terminal oxidase that are differentially regulated as a response to changing environmental conditions. These oxidoreductases catalyze the reduction of molecular oxygen to water and contribute to the proton motive force. The cytochrome bo oxidase (cyt bo ) acts as the primary terminal oxidase under atmospheric oxygen levels, whereas the bd-type oxidase is most abundant under microaerobic conditions.
View Article and Find Full Text PDFCytochrome bd-type quinol oxidases catalyze the reduction of molecular oxygen to water in the respiratory chain of many human-pathogenic bacteria. They are structurally unrelated to mitochondrial cytochrome c oxidases and are therefore a prime target for the development of antimicrobial drugs. We determined the structure of the cytochrome bd-I oxidase by single-particle cryo-electron microscopy to a resolution of 2.
View Article and Find Full Text PDFMultidrug and toxic compound extrusion (MATE) transporters mediate excretion of xenobiotics and toxic metabolites, thereby conferring multidrug resistance in bacterial pathogens and cancer cells. Structural information on the alternate conformational states and knowledge of the detailed mechanism of MATE transport are of great importance for drug development. However, the structures of MATE transporters are only known in V-shaped outward-facing conformations.
View Article and Find Full Text PDFBackground: Head and neck squamous cell carcinoma (HNSCC) is the sixth leading cancer worldwide. They are typically characterized by a high incidence of local recurrence, which is the most common cause of death in HNSCC patients. TP53 is the most frequently mutated gene in HNSCC and patients carrying TP53 mutations are associated with a higher probability to develop local recurrence.
View Article and Find Full Text PDFTamoxifen (Nolvadex) is one of the most widely used and effective therapeutic agent for breast cancer. It benefits nearly 75% of patients with estrogen receptor (ER)-positive breast cancer that receive this drug. Its effectiveness is mainly attributed to its capacity to function as an ER antagonist, blocking estrogen binding sites on the receptor, and inhibiting the proliferative action of the receptor-hormone complex.
View Article and Find Full Text PDFMater Sci Eng C Mater Biol Appl
October 2017
Graphene quantum dots (GQDs) are new efficient nanomaterials used in therapeutic applications. In this study, blue fluorescent nitrogen-doped GQDs (N-GQDs) were synthesized by a hydrothermal method via pyrolisis of citric acid as the carbon source and urea as the nitrogen source. The existence of doped nitrogen in GQDs was confirmed by FTIR characterization.
View Article and Find Full Text PDFZinc oxide nanoparticles are very toxic, but their agglomeration reduces their lethal cytotoxic effects. Here we tested the hypothesis that conjugation of ZnO nanoparticles via Meso-Tetra (4-Carboxyphenyl) Porphyrin (MTCP) could provide electrostatic or steric stabilization of ZnO nanoparticles and increase their cytotoxic effects. The cytotoxicity and cell death induction were assessed using two human breast adenocarcinoma cell lines (MCF-7 and MDA-MB-468).
View Article and Find Full Text PDFPolymer architecture can influence biodistribution and the mode of presentation of bioactive agents to cells. Herein delivery, loading efficiency, and mode of cellular entry of polymer conjugates of the photosensitizer Meso-Tetra (4-Carboxyphenyl) Porphyrine (MTCP) are examined when attached to hyperbranched amine terminated poly(amido amine) (PAMAM) dendrimer or random coil linear N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer containing free amines in the side chains. The in vitro dark cytotoxicity and phototoxicity of MTCP and related conjugates are assessed on mouth epidermal carcinoma (KB) and human adenocarcinoma alveolar basal epithelial (A549) cells.
View Article and Find Full Text PDFBackground/aim: Almond hull is produced in high amounts and mostly used as livestock feed. This study was designed to examine the impact of almond hull powder (AHP) administration on lipid profile and antioxidant activities in plasma and liver in hyperlipidemic rats.
Materials And Methods: As the first step, the antioxidant capacity and radical scavenging activity of AHP were determined using calorimetric methods.