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International Journal of Molecular... Jul 2021Extracellular vesicles (EVs) are membranous, rounded vesicles released by prokaryotic and eukaryotic cells in their normal and pathophysiological states. These vesicles... (Review)
Review
Extracellular vesicles (EVs) are membranous, rounded vesicles released by prokaryotic and eukaryotic cells in their normal and pathophysiological states. These vesicles form a network of intercellular communication as they can transfer cell- and function-specific information (lipids, proteins and nucleic acids) to different cells and thus alter their function. Fungi are not an exception; they also release EVs to the extracellular space. The vesicles can also be retained in the periplasm as periplasmic vesicles (PVs) and the cell wall. Such fungal vesicles play various specific roles in the lives of these organisms. They are involved in creating wall architecture and maintaining its integrity, supporting cell isolation and defence against the environment. In the case of pathogenic strains, they might take part in the interactions with the host and affect the infection outcomes. The economic importance of fungi in manufacturing high-quality nutritional and pharmaceutical products and in remediation is considerable. The analysis of fungal EVs opens new horizons for diagnosing fungal infections and developing vaccines against mycoses and novel applications of nanotherapy and sensors in industrial processes.
Topics: Biological Transport, Active; Extracellular Vesicles; Fungal Proteins; Fungi; Genes, Fungal; Host Microbial Interactions; Humans; Models, Biological; Mycoses; RNA, Fungal
PubMed: 34281276
DOI: 10.3390/ijms22137221 -
Current Opinion in Microbiology Apr 2021Cells must build and maintain at least one membrane that surrounds essential cellular components and provides structural integrity. Gram-negative bacteria possess an... (Review)
Review
Cells must build and maintain at least one membrane that surrounds essential cellular components and provides structural integrity. Gram-negative bacteria possess an inner membrane, which separates the aqueous cytoplasmic and periplasmic compartments, and an outer membrane, which surrounds the periplasm. The outer membrane is an asymmetric bilayer with phospholipids in its inner leaflet and lipopolysaccharides in its outer leaflet. This structure provides cellular integrity and prevents the entry of many toxic compounds into the cell. Constructing the outer membrane is challenging, since its lipid constituents must be synthesized within the inner membrane, transported across the periplasm, and ultimately assembled into an asymmetric structure. This review highlights major recent advances in our understanding of the mechanism and structure of the intermembrane, multi-protein machine that transports lipopolysaccharide across the cell envelope. Although our understanding of phospholipid transport is very limited, we also provide a brief update on this topic.
Topics: Bacterial Outer Membrane Proteins; Biological Transport; Cell Membrane; Escherichia coli Proteins; Gram-Negative Bacteria; Lipopolysaccharides; Phospholipids
PubMed: 33601322
DOI: 10.1016/j.mib.2021.01.006 -
Current Opinion in Chemical Biology Feb 2022Metallo-β-lactamases (MBLs) are zinc-dependent hydrolases that inactivate virtually all β-lactam antibiotics. The expression of MBLs by Gram-negative bacteria severely... (Review)
Review
Metallo-β-lactamases (MBLs) are zinc-dependent hydrolases that inactivate virtually all β-lactam antibiotics. The expression of MBLs by Gram-negative bacteria severely limits the therapeutic options to treat infections. MBLs bind the essential metal ions in the bacterial periplasm, and their activity is challenged upon the zinc starvation conditions elicited by the native immune response. Metal depletion compromises both the enzyme activity and stability in the periplasm, impacting on the resistance profile in vivo. Thus, novel inhibitory approaches involve the use of chelating agents or metal-based drugs that displace the native metal ion. However, newer MBL variants incorporate mutations that improve their metal binding abilities or stabilize the metal-depleted form, revealing that metal starvation is a driving force acting on MBL evolution. Future challenges require addressing the gap between in cell and in vitro studies, dissecting the mechanism for MBL metalation and determining the metal content in situ.
Topics: Anti-Bacterial Agents; Bacteria; Gram-Negative Bacteria; Zinc; beta-Lactamases
PubMed: 34864439
DOI: 10.1016/j.cbpa.2021.102103 -
Microbiology Spectrum Jul 2019Periplasmic flagella are complex nanomachines responsible for distinctive morphology and motility of spirochetes. Although bacterial flagella have been extensively... (Review)
Review
Periplasmic flagella are complex nanomachines responsible for distinctive morphology and motility of spirochetes. Although bacterial flagella have been extensively studied for several decades in the model systems and , our understanding of periplasmic flagella in many disease-causing spirochetes remains incomplete. Recent advances, including molecular genetics, biochemistry, structural biology, and cryo-electron tomography, have greatly increased our understanding of structure and function of periplasmic flagella. In this chapter, we summarize some of the recent findings that provide new insights into the structure, assembly, and function of periplasmic flagella.
Topics: Bacterial Proteins; Borrelia burgdorferi; Escherichia coli; Flagella; Periplasm; Salmonella enterica
PubMed: 31373267
DOI: 10.1128/microbiolspec.PSIB-0030-2019 -
Biochimica Et Biophysica Acta.... Dec 2020The vesicular glutamate transporters (VGLUTs) bind and move glutamate (Glu) from the cytosol into the lumen of synaptic vesicles using a H-electrochemical gradient (ΔpH... (Review)
Review
The vesicular glutamate transporters (VGLUTs) bind and move glutamate (Glu) from the cytosol into the lumen of synaptic vesicles using a H-electrochemical gradient (ΔpH and Δψ) generated by the vesicular H-ATPase. VGLUTs show very low Glu binding and to date, no three-dimensional structure has been elucidated. Prior studies have attempted to identify the key residues involved in binding VGLUT substrates and inhibitors using homology models and docking experiments. Recently, the inward and outward oriented crystal structures of d-galactonate transporter (DgoT) emerged as possible structure templates for VGLUT. In this review, a new homology model for VGLUT2 based on DgoT has been developed and used to conduct docking experiments to identify and differentiate residues and binding orientations involved in ligand interactions. This review describes small molecule-ligand interactions including docking using a VGLUT2 homology model derived from DgoT.
Topics: Binding Sites; Calcium-Binding Proteins; Glutamic Acid; Humans; Molecular Docking Simulation; Monosaccharide Transport Proteins; Periplasmic Binding Proteins; Protein Isoforms; Substrate Specificity; Thermodynamics; Vesicular Glutamate Transport Proteins
PubMed: 31923412
DOI: 10.1016/j.bbamem.2020.183175 -
Applied and Environmental Microbiology Apr 2021Extracellular electron transfer (EET) is an important biological process in microbial physiology as found in dissimilatory metal oxidation/reduction and interspecies... (Review)
Review
Extracellular electron transfer (EET) is an important biological process in microbial physiology as found in dissimilatory metal oxidation/reduction and interspecies electron transfer in syntrophy in natural environments. EET also plays a critical role in microorganisms relevant to environmental biotechnology in metal-contaminated areas, metal corrosion, bioelectrochemical systems, and anaerobic digesters. species exist in a diversity of natural and artificial environments. One of the outstanding features of species is the capability of direct EET with solid electron donors and acceptors, including metals, electrodes, and other cells. Therefore, species are pivotal in environmental biogeochemical cycles and biotechnology applications. , a representative species, has been studied for direct EET as a model microorganism. employs electrically conductive pili (e-pili) and -type cytochromes for the direct EET. The biological function and electronics applications of the e-pili have been reviewed recently, and this review focuses on the cytochromes. species have an unusually large number of cytochromes encoded in their genomes. Unlike most other microorganisms, species localize multiple cytochromes in each subcellular fraction, outer membrane, periplasm, and inner membrane, as well as in the extracellular space, and differentially utilize these cytochromes for EET with various electron donors and acceptors. Some of the cytochromes are functionally redundant. Thus, the EET in is complicated. coordinates the cytochromes with other cellular components in the elaborate EET system to flourish in the environment.
Topics: Bacterial Outer Membrane; Cytochromes; Electron Transport; Geobacter; Intracellular Membranes; Periplasm
PubMed: 33741623
DOI: 10.1128/AEM.03109-20 -
Biochimie Feb 2023Bacteria protect themselves from the toxicity of antimicrobial metabolites they produce through several strategies. In one resistance mechanism, bacteria assemble a... (Review)
Review
Bacteria protect themselves from the toxicity of antimicrobial metabolites they produce through several strategies. In one resistance mechanism, bacteria assemble a non-toxic precursor on an N-acyl-d-asparagine prodrug motif in the cytoplasm, then export it to the periplasm where a dedicated d-amino peptidase hydrolyzes the prodrug motif. These prodrug-activating peptidases contain an N-terminal periplasmic S12 hydrolase domain and C-terminal transmembrane domains (TMDs) of varying lengths: type I peptidases contain three transmembrane helices, and type II peptidases have an additional C-terminal ABC half-transporter. We review studies which have addressed the role of the TMD in function, the substrate specificity, and the biological assembly of ClbP, the type I peptidase that activates colibactin. We use modeling and sequence analyses to extend those insights to other prodrug-activating peptidases and ClbP-like proteins which are not part of prodrug resistance gene clusters. These ClbP-like proteins may play roles in the biosynthesis or degradation of other natural products, including antibiotics, may adopt different TMD folds, and have different substrate specificity compared to prodrug-activating homologs. Finally, we review the data supporting the long-standing hypothesis that ClbP interacts with transporters in the cell and that this association is important for the export of other natural products. Future investigations of this hypothesis as well as of the structure and function of type II peptidases will provide a complete account of the role of prodrug-activating peptidases in the activation and secretion of bacterial toxins.
Topics: Peptide Hydrolases; Prodrugs; Escherichia coli; Escherichia coli Proteins
PubMed: 36803695
DOI: 10.1016/j.biochi.2022.07.019 -
Science Advances Jul 2023Semiconductor-based biointerfaces are typically established either on the surface of the plasma membrane or within the cytoplasm. In Gram-negative bacteria, the...
Semiconductor-based biointerfaces are typically established either on the surface of the plasma membrane or within the cytoplasm. In Gram-negative bacteria, the periplasmic space, characterized by its confinement and the presence of numerous enzymes and peptidoglycans, offers additional opportunities for biomineralization, allowing for nongenetic modulation interfaces. We demonstrate semiconductor nanocluster precipitation containing single- and multiple-metal elements within the periplasm, as observed through various electron- and x-ray-based imaging techniques. The periplasmic semiconductors are metastable and display defect-dominant fluorescent properties. Unexpectedly, the defect-rich (i.e., the low-grade) semiconductor nanoclusters produced in situ can still increase adenosine triphosphate levels and malate production when coupled with photosensitization. We expand the sustainability levels of the biohybrid system to include reducing heavy metals at the primary level, building living bioreactors at the secondary level, and creating semi-artificial photosynthesis at the tertiary level. The biomineralization-enabled periplasmic biohybrids have the potential to serve as defect-tolerant platforms for diverse sustainable applications.
Topics: Periplasm; Biomineralization; Cell Membrane; Cytoplasm; Photosynthesis
PubMed: 37478187
DOI: 10.1126/sciadv.adg5858 -
MBio Apr 2023Over the billions of years that bacteria have been around, they have evolved several sophisticated protein secretion nanomachines to deliver toxins, hydrolytic enzymes,... (Review)
Review
Over the billions of years that bacteria have been around, they have evolved several sophisticated protein secretion nanomachines to deliver toxins, hydrolytic enzymes, and effector proteins into their environments. Of these, the type II secretion system (T2SS) is used by Gram-negative bacteria to export a wide range of folded proteins from the periplasm across the outer membrane. Recent findings have demonstrated that components of the T2SS are localized in mitochondria of some eukaryotic lineages, and their behavior is consistent with the presence of a mitochondrial T2SS-derived system (miT2SS). This review focuses on recent advances in the field and discusses open questions concerning the function and evolution of miT2SSs.
Topics: Type II Secretion Systems; Bacterial Proteins; Gram-Negative Bacteria; Periplasm; Bacterial Secretion Systems
PubMed: 36971557
DOI: 10.1128/mbio.03145-22 -
Chemical Science Aug 2021DsbA is a ubiquitous bacterial oxidoreductase that associates with substrates during and after translocation, yet its involvement in protein folding and translocation...
DsbA is a ubiquitous bacterial oxidoreductase that associates with substrates during and after translocation, yet its involvement in protein folding and translocation remains an open question. Here we demonstrate a redox-controlled chaperone activity of DsbA, on both cysteine-containing and cysteine-free substrates, using magnetic tweezers-based single molecule force spectroscopy that enables independent measurements of oxidoreductase activity and chaperone behavior. Interestingly we found that this chaperone activity is tuned by the oxidation state of DsbA; oxidized DsbA is a strong promoter of folding, but the effect is weakened by the reduction of the catalytic CXXC motif. We further localize the chaperone binding site of DsbA using a seven-residue peptide which effectively blocks the chaperone activity. We found that the DsbA assisted folding of proteins in the periplasm generates enough mechanical work to decrease the ATP consumption needed for periplasmic translocation by up to 33%.
PubMed: 34522308
DOI: 10.1039/d1sc03048e