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PLoS Biology Jan 2018Gram-negative bacteria are surrounded by two membrane bilayers separated by a space termed the periplasm. The periplasm is a multipurpose compartment separate from the...
Gram-negative bacteria are surrounded by two membrane bilayers separated by a space termed the periplasm. The periplasm is a multipurpose compartment separate from the cytoplasm whose distinct reducing environment allows more efficient and diverse mechanisms of protein oxidation, folding, and quality control. The periplasm also contains structural elements and important environmental sensing modules, and it allows complex nanomachines to span the cell envelope. Recent work indicates that the size or intermembrane distance of the periplasm is controlled by periplasmic lipoproteins that anchor the outer membrane to the periplasmic peptidoglycan polymer. This periplasm intermembrane distance is critical for sensing outer membrane damage and dictates length of the flagellar periplasmic rotor, which controls motility. These exciting results resolve longstanding debates about whether the periplasmic distance has a biological function and raise the possibility that the mechanisms for maintenance of periplasmic size could be exploited for antibiotic development.
Topics: Bacterial Outer Membrane Proteins; Bacterial Proteins; Cell Membrane; Cell Wall; Cytoplasm; Gram-Negative Bacteria; Peptidoglycan; Periplasm; Spatial Analysis
PubMed: 29342145
DOI: 10.1371/journal.pbio.2004935 -
Current Opinion in Structural Biology Apr 2021The Ton complex is a molecular motor that uses the proton gradient at the inner membrane of Gram-negative bacteria to apply forces on outer membrane proteins, allowing... (Review)
Review
The Ton complex is a molecular motor that uses the proton gradient at the inner membrane of Gram-negative bacteria to apply forces on outer membrane proteins, allowing active transport of nutrients into the periplasmic space. For decades, contradictory data has been reported on the structure and stoichiometry of the Ton complex. However, recent reports strongly support a subunit stoichiometry of 5:2 for the ExbB-ExbD subcomplex. In this review, we summarize the recent discoveries of the structures and proposed mechanisms of the Ton system, as well as similar protein motor complexes in Gram-negative bacteria.
Topics: Bacterial Proteins; Escherichia coli; Escherichia coli Proteins; Gram-Negative Bacteria; Membrane Proteins; Periplasm
PubMed: 33157479
DOI: 10.1016/j.sbi.2020.09.014 -
Molecular Plant-microbe Interactions :... Dec 2017The functional role of the periplasm of nitrogen-fixing bacteroids has not been determined. Proteins were isolated from the periplasm and cytoplasm of Bradyrhizobium...
The functional role of the periplasm of nitrogen-fixing bacteroids has not been determined. Proteins were isolated from the periplasm and cytoplasm of Bradyrhizobium diazoefficiens bacteroids and were analyzed using liquid chromatography tandem mass spectrometry proteomics. Identification of bacteroid periplasmic proteins was aided by periplasm prediction programs. Approximately 40% of all the proteins identified as periplasmic in the B. diazoefficiens genome were found expressed in the bacteroid form of the bacteria, indicating the periplasm is a metabolically active symbiotic space. The bacteroid periplasm possesses many fatty acid metabolic enzymes, which was in contrast to the bacteroid cytoplasm. Amino acid analysis of the periplasm revealed an abundance of phosphoserine, phosphoethanolamine, and glycine, which are metabolites of phospholipid metabolism. These results suggest the periplasm is a unique space and not a continuum with the peribacteroid space. A number of plant proteins were found in the periplasm fraction, which suggested contamination. However, antibodies to two of the identified plant proteins, histone H2A and lipoxygenase, yielded immunogold labeling that demonstrated the plant proteins were specifically targeted to the bacteroids. This suggests that the periplasm is an interkingdom symbiotic space containing proteins from both the bacteroid and the plant.
Topics: Amino Acids; Bacterial Proteins; Base Sequence; Periplasm; Root Nodules, Plant; Glycine max; Symbiosis
PubMed: 29028412
DOI: 10.1094/MPMI-12-16-0264-R -
Journal of Molecular Biology Feb 2024The width of the periplasmic space of Gram-negative bacteria is only about 25-30 nm along the long axis of the cell, which affects free diffusion of (macro)molecules....
The width of the periplasmic space of Gram-negative bacteria is only about 25-30 nm along the long axis of the cell, which affects free diffusion of (macro)molecules. We have performed single-particle displacement measurements and diffusion simulation studies to determine the impact of confinement on the apparent mobility of proteins in the periplasm of Escherichia coli. The diffusion of a reporter protein and of OsmY, an osmotically regulated periplasmic protein, is characterized by a fast and slow component regardless of the osmotic conditions. The diffusion coefficient of the fast fraction increases upon osmotic upshift, in agreement with a decrease in macromolecular crowding of the periplasm, but the mobility of the slow (immobile) fraction is not affected by the osmotic stress. We observe that the confinement created by the inner and outer membranes results in a lower apparent diffusion coefficient, but this can only partially explain the slow component of diffusion in the particle displacement measurements, suggesting that a fraction of the proteins is hindered in its mobility by large periplasmic structures. Using particle-based simulations, we have determined the confinement effect on the apparent diffusion coefficient of the particles for geometries akin the periplasmic space of Gram-negative bacteria.
Topics: Diffusion; Escherichia coli; Escherichia coli Proteins; Osmotic Pressure; Periplasm; Single Molecule Imaging
PubMed: 38143021
DOI: 10.1016/j.jmb.2023.168420 -
Amino Acids May 2013Siderophore production and utilization is one of the major strategies deployed by bacteria to get access to iron, a key nutrient for bacterial growth. The biological... (Review)
Review
Fate of ferrisiderophores after import across bacterial outer membranes: different iron release strategies are observed in the cytoplasm or periplasm depending on the siderophore pathways.
Siderophore production and utilization is one of the major strategies deployed by bacteria to get access to iron, a key nutrient for bacterial growth. The biological function of siderophores is to solubilize iron in the bacterial environment and to shuttle it back to the cytoplasm of the microorganisms. This uptake process for Gram-negative species involves TonB-dependent transporters for translocation across the outer membranes. In Escherichia coli and many other Gram-negative bacteria, ABC transporters associated with periplasmic binding proteins import ferrisiderophores across cytoplasmic membranes. Recent data reveal that in some siderophore pathways, this step can also be carried out by proton-motive force-dependent permeases, for example the ferrichrome and ferripyochelin pathways in Pseudomonas aeruginosa. Iron is then released from the siderophores in the bacterial cytoplasm by different enzymatic mechanisms depending on the nature of the siderophore. Another strategy has been reported for the pyoverdine pathway in P. aeruginosa: iron is released from the siderophore in the periplasm and only siderophore-free iron is transported into the cytoplasm by an ABC transporter having two atypical periplasmic binding proteins. This review presents recent findings concerning both ferrisiderophore and siderophore-free iron transport across bacterial cytoplasmic membranes and considers current knowledge about the mechanisms involved in iron release from siderophores.
Topics: ATP-Binding Cassette Transporters; Animals; Bacterial Proteins; Biological Transport; Cell Membrane; Humans; Iron; Membrane Transport Proteins; Periplasm; Pseudomonas aeruginosa; Siderophores
PubMed: 23443998
DOI: 10.1007/s00726-013-1468-2 -
Biomolecules Apr 2020Spirochetes can be distinguished from other flagellated bacteria by their long, thin, spiral (or wavy) cell bodies and endoflagella that reside within the periplasmic... (Review)
Review
Spirochetes can be distinguished from other flagellated bacteria by their long, thin, spiral (or wavy) cell bodies and endoflagella that reside within the periplasmic space, designated as periplasmic flagella (PFs). Some members of the spirochetes are pathogenic, including the causative agents of syphilis, Lyme disease, swine dysentery, and leptospirosis. Furthermore, their unique morphologies have attracted attention of structural biologists; however, the underlying physics of viscoelasticity-dependent spirochetal motility is a longstanding mystery. Elucidating the molecular basis of spirochetal invasion and interaction with hosts, resulting in the appearance of symptoms or the generation of asymptomatic reservoirs, will lead to a deeper understanding of host-pathogen relationships and the development of antimicrobials. Moreover, the mechanism of propulsion in fluids or on surfaces by the rotation of PFs within the narrow periplasmic space could be a designing base for an autonomously driving micro-robot with high efficiency. This review describes diverse morphology and motility observed among the spirochetes and further summarizes the current knowledge on their mechanisms and relations to pathogenicity, mainly from the standpoint of experimental biophysics.
Topics: Flagella; Movement; Periplasm; Spirochaetales
PubMed: 32260454
DOI: 10.3390/biom10040550 -
Biochemical Society Transactions Dec 2012Colicins are protein antibiotics produced by Escherichia coli to kill closely related non-identical competing species. They have taken advantage of the promiscuity of... (Review)
Review
Colicins are protein antibiotics produced by Escherichia coli to kill closely related non-identical competing species. They have taken advantage of the promiscuity of several proteins in the cell envelope for entry into the bacterial cell. The Tol-Pal system comprises one such ensemble of periplasmic and membrane-associated interacting proteins that links the IM (inner membrane) and OM (outer membrane) and provides the cell with a structural scaffold for cell division and energy transduction. Central to the Tol-Pal system is the TolA hub protein which forms protein-protein interactions with all other members and also with extrinsic proteins such as colicins A, E1, E2-E9 and N, and the coat proteins of the Ff family of filamentous bacteriophages. In the present paper, we review the role of TolA in the translocation of colicin A through the recently determined crystal structure of the complex of TolA with a translocation domain peptide of ColA (TA53-107), we demonstrate that TA53-107 binds to TolA at a novel binding site and compare the interactions of TolA with other colicins that use the Tol-Pal system for cell entry substantiating further the role of TolA as a periplasmic hub protein.
Topics: Binding Sites; Colicins; Escherichia coli; Escherichia coli Proteins; Models, Molecular; Peptide Fragments; Periplasm; Periplasmic Proteins; Protein Binding; Protein Structure, Secondary; Protein Structure, Tertiary; Protein Transport
PubMed: 23176500
DOI: 10.1042/BST20120239 -
Methods in Molecular Biology (Clifton,... 2017Spirochetes are bacteria distinguished by an undulate or helical cell body and intracellular flagellar called periplasmic flagella or endoflagella. Spirochetes translate...
Spirochetes are bacteria distinguished by an undulate or helical cell body and intracellular flagellar called periplasmic flagella or endoflagella. Spirochetes translate by rotating the cell body. In this chapter, we show a method for simultaneous measurement of the cell body rotation and swimming speed in individual spirochete cells. We also describe a simple chemotaxis assay capable of observing the response of spirochete in real time under a microscope and quantitatively evaluating the response magnitude to attractants and repellents.
Topics: Bacterial Proteins; Cell Movement; Chemotaxis; Flagella; Periplasm; Rotation; Spirochaetales
PubMed: 28389959
DOI: 10.1007/978-1-4939-6927-2_19 -
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 -
EcoSal Plus Jun 2017Among all the systems developed by enterobacteria to face osmotic stress, only osmoregulated periplasmic glucans (OPGs) were found to be modulated during osmotic fluxes....
Among all the systems developed by enterobacteria to face osmotic stress, only osmoregulated periplasmic glucans (OPGs) were found to be modulated during osmotic fluxes. First detected in 1973 by E.P. Kennedy's group in a study of phospholipid turnover in , OPGs have been shown across alpha, beta, and gamma subdivisions of the proteobacteria. Discovery of OPG-like compounds in the epsilon subdivision strongly suggested that the presence of periplasmic glucans is essential for almost all proteobacteria. This article offers an overview of the different classes of OPGs. Then, the biosynthesis of OPGs and their regulation in and other species are discussed. Finally, the biological role of OPGs is developed. Beyond structural function, OPGs are involved in pathogenicity, in particular, by playing a role in signal transduction pathways. Recently, OPG synthesis proteins have been suggested to control cell division and growth rate.
Topics: Enterobacteriaceae; Escherichia coli; Gene Expression Regulation, Bacterial; Glucans; Osmoregulation; Osmotic Pressure; Periplasm; Virulence; Water-Electrolyte Balance
PubMed: 28593831
DOI: 10.1128/ecosalplus.ESP-0001-2017