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https://www.readbyqxmd.com/read/29935042/a-pleiotropic-role-of-flag-in-regulating-the-cell-morphogenesis-and-flagellar-homeostasis-at-the-cell-poles-of-treponema-denticola
#1
Kurni Kurniyati, Jun Liu, Jing-Ren Zhang, Yunjiang Min, Chunhao Li
FlaG homolog has been found in several bacteria including spirochetes; however, its function is poorly characterized. In this report, we investigated the role of TDE1473, a putative FlaG, in the spirochete Treponema denticola, a keystone pathogen of periodontitis. TDE1473 resides in a large gene operon that is controlled by a σ70 -like promoter and encodes a putative FlaG protein of 123 amino acids. TDE1473 can be detected in the periplasmic flagella (PFs) of T. denticola, suggesting that it is a flagella-associated protein...
June 23, 2018: Cellular Microbiology
https://www.readbyqxmd.com/read/29933078/multivalent-targeting-and-killing-of-her2-overexpressing-breast-carcinoma-cells-with-methotrexate-encapsulated-tetra-specific-non-overlapping-variable-domain-heavy-chain-anti-her2-antibody-peg-liposomes-in-vitro-proof-of-concept
#2
Shahryar Khoshtinat Nikkhoi, Fatemeh Rahbarizadeh, Davoud Ahmadvand, Seyed Moein Moghimi
The variable domain of the heavy chain antibodies (VHHs) is the smallest (15 kDa) intact single domain antigen-binding fragment. VHHs often exhibit sub-nanomolar affinity for their designated targets and therefore are receiving increasing attention in molecular targeting and nanomedicine engineering. We cloned and expressed four non-overlapping anti-HER2 VHHs in a prokaryotic expression system that yielded periplasmic expression of disulfide-bonded VHHs. Purified VHHs, before and after thiolation, were characterized by Western blot and their functionality against the ecto-domain of HER2 receptor was confirmed by ELISA and flow cytometry...
June 19, 2018: European Journal of Pharmaceutical Sciences
https://www.readbyqxmd.com/read/29931811/bacteroides-fragilis-requires-the-ferrous-iron-transporter-feoab-and-the-cobn-like-proteins-btus1-and-btus2-for-assimilation-of-iron-released-from-heme
#3
Edson R Rocha, Hector A Bergonia, Svetlana Gerdes, Charles Jeffrey Smith
The intestinal commensal and opportunistic anaerobic pathogen Bacteroides fragilis has an essential requirement for both heme and free iron to support growth in extraintestinal infections. In the absence of free iron, B. fragilis can utilize heme as the sole source of iron. However, the mechanisms to remove iron from heme are not completely understood. In this study, we show that the inner membrane ferrous iron transporter ∆feoAB mutant strain is no longer able to grow with heme as the sole source of iron...
June 21, 2018: MicrobiologyOpen
https://www.readbyqxmd.com/read/29931366/molecular-cloning-expression-and-biochemical-characterization-of-periplasmic-nitrate-reductase-from-campylobacter-jejuni
#4
Breeanna Mintmier, Jennifer M McGarry, Courtney Sparacino-Watkins, Joseph Sallmen, Katrin Fischer-Schrader, Axel Magalon, Joseph R McCormick, John F Stolz, Günter Schwarz, Daniel J Bain, Partha Basu
Campylobacter jejuni, a human gastrointestinal pathogen, uses nitrate for growth under microaerophilic conditions using periplasmic nitrate reductase (Nap). The catalytic subunit, NapA, contains two prosthetic groups, an iron sulfur cluster and a molybdenum cofactor. Here we describe the cloning, expression, purification, Michaelis-Menten kinetics (kcat of 5.91 ± 0.18 s-1 and a KM (nitrate) of 3.40 ± 0.44 μM) in solution using methyl viologen as an electron donor. The data suggest that the high affinity of NapA for nitrate could support growth of C...
June 19, 2018: FEMS Microbiology Letters
https://www.readbyqxmd.com/read/29930105/correction-for-ruby-et-al-activation-of-the-innate-immune-system-by-treponema-denticola-periplasmic-flagella-through-toll-like-receptor-2
#5
John Ruby, Michael Martin, Michael J Passineau, Valentina Godovikova, J Christopher Fenno, Hui Wu
No abstract text is available yet for this article.
July 2018: Infection and Immunity
https://www.readbyqxmd.com/read/29915043/sodium-and-proton-coupling-in-the-conformational-cycle-of-a-mate-antiporter-from-vibrio-cholerae
#6
Derek P Claxton, Kevin L Jagessar, P Ryan Steed, Richard A Stein, Hassane S Mchaourab
Secondary active transporters belonging to the multidrug and toxic compound extrusion (MATE) family harness the potential energy of electrochemical ion gradients to export a broad spectrum of cytotoxic compounds, thus contributing to multidrug resistance. The current mechanistic understanding of ion-coupled substrate transport has been informed by a limited set of MATE transporter crystal structures from multiple organisms that capture a 12-transmembrane helix topology adopting similar outward-facing conformations...
June 18, 2018: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/29904084/signature-of-pareto-optimization-in-the-escherichia-coli-proteome
#7
Loren Koçillari, Piero Fariselli, Antonio Trovato, Flavio Seno, Amos Maritan
Proteins have coevolved with cellular environments to improve or preserve their functions, maintaining at the same time the degree of hydrophobicity necessary to fold correctly and enough solubility to perform their biological roles. Here, we study the Escherichia coli proteome using a Pareto front analysis in the solubility-hydrophobicity space. The results indicate the existence of a Pareto optimal front, a triangle whose vertices correspond to archetypal proteins specialized in distinct tasks, such as regulatory processes, membrane transport, outer-membrane pore formation, catalysis, and binding...
June 14, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29899515/nutrient-transport-suggests-an-evolutionary-basis-for-charged-archaeal-surface-layer-proteins
#8
Po-Nan Li, Jonathan Herrmann, Bradley B Tolar, Frédéric Poitevin, Rasika Ramdasi, John R Bargar, David A Stahl, Grant J Jensen, Christopher A Francis, Soichi Wakatsuki, Henry van den Bedem
Surface layers (S-layers) are two-dimensional, proteinaceous, porous lattices that form the outermost cell envelope component of virtually all archaea and many bacteria. Despite exceptional sequence diversity, S-layer proteins (SLPs) share important characteristics such as their ability to form crystalline sheets punctuated with nano-scale pores, and their propensity for charged amino acids, leading to acidic or basic isoelectric points. However, the precise function of S-layers, or the role of charged SLPs and how they relate to cellular metabolism is unknown...
June 13, 2018: ISME Journal
https://www.readbyqxmd.com/read/29896187/exploring-the-denitrification-proteome-of-paracoccus-denitrificans-pd1222
#9
Alfonso Olaya-Abril, Jesús Hidalgo-Carrillo, Víctor M Luque-Almagro, Carlos Fuentes-Almagro, Francisco J Urbano, Conrado Moreno-Vivián, David J Richardson, María D Roldán
Denitrification is a respiratory process that produces nitrous oxide as an intermediate, which may escape to the atmosphere before its reduction to dinitrogen through the nitrous oxide reductase NosZ. In this work, the denitrification process carried out by Paracoccus denitrificans PD1222 has been explored through a quantitative proteomic analysis. Under anaerobic conditions, with nitrate as sole nitrogen source, the synthesis of all the enzymes involved in denitrification, the respiratory nitrate, nitrite, nitric oxide, and nitrous oxide reductases, was increased...
2018: Frontiers in Microbiology
https://www.readbyqxmd.com/read/29894804/evaluation-of-in-vitro-refolding-vs-cold-shock-expression-production-of-a-low-yielding-single-chain-variable-fragment
#10
Jan-G Vermeulen, Felicity Burt, Esta van Heerden, Errol Cason, Muriel Meiring
The development of therapeutic antibodies in their various forms has been a constant challenge since the development of the first monoclonal antibodies in 1975. This is especially true for the development of therapeutic single chain variable (scFv) fragments in Escherichia coli. In a previous study the selection of a tissue factor inhibiting single chain variable fragment (TFI-scFv) isolated from the Thomlinson I + J phage libraries was described. Although the initial findings were promising, additional characterization of the antibody fragment and subsequent application was hampered due low protein yield...
June 9, 2018: Protein Expression and Purification
https://www.readbyqxmd.com/read/29893830/conformational-plasticity-of-molecular-chaperones-involved-in-periplasmic-and-outer-membrane-protein-folding
#11
Guillaume Mas, Sebastian Hiller
How proteins reach their native conformation and location has been a major question of biology during the last 50 years. To counterbalance protein misfolding and the accumulation of aggregation products, a complex network of chaperones and proteases takes care of protein quality control in the cell. Such a chaperone network is in place in the periplasm of Gram-negative bacteria, where it is necessary for the survival of the bacteria as well as for outer membrane biogenesis. First mechanistic insights into the periplasmic chaperones that comprise this system came from crystal structures of their apo states...
July 1, 2018: FEMS Microbiology Letters
https://www.readbyqxmd.com/read/29892271/antibiotic-resistance-mediated-by-the-macb-abc-transporter-family-a-structural-and-functional-perspective
#12
REVIEW
Nicholas P Greene, Elise Kaplan, Allister Crow, Vassilis Koronakis
The MacB ABC transporter forms a tripartite efflux pump with the MacA adaptor protein and TolC outer membrane exit duct to expel antibiotics and export virulence factors from Gram-negative bacteria. Here, we review recent structural and functional data on MacB and its homologs. MacB has a fold that is distinct from other structurally characterized ABC transporters and uses a unique molecular mechanism termed mechanotransmission. Unlike other bacterial ABC transporters, MacB does not transport substrates across the inner membrane in which it is based, but instead couples cytoplasmic ATP hydrolysis with transmembrane conformational changes that are used to perform work in the extra-cytoplasmic space...
2018: Frontiers in Microbiology
https://www.readbyqxmd.com/read/29891657/bacterial-iron-acquisition-mediated-by-outer-membrane-translocation-and-cleavage-of-a-host-protein
#13
Khedidja Mosbahi, Marta Wojnowska, Amaya Albalat, Daniel Walker
Iron is an essential micronutrient for most bacteria and is obtained from iron-chelating siderophores or directly from iron-containing host proteins. For Gram-negative bacteria, classical iron transport systems consist of an outer membrane receptor, a periplasmic binding protein, and an inner membrane ABC transporter, which work in concert to deliver iron from the cell surface to the cytoplasm. We recently showed that Pectobacterium spp. are able to acquire iron from ferredoxin, a small and stable 2Fe-2S iron sulfur cluster containing protein and identified the ferredoxin receptor, FusA, a TonB-dependent receptor that binds ferredoxin on the cell surface...
June 11, 2018: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/29890437/positive-effects-of-bio-nano-pd-0-toward-direct-electron-transfer-in-pseudomona-putida-and-phenol-biodegradation
#14
Zhuyu Niu, Yating Jia, Yuancai Chen, Yongyou Hu, Junfeng Chen, Yuancai Lv
This study constructed a biological-inorganic hybrid system including Pseudomonas putida (P. putida) and bioreduced Pd (0) nanoparticles (NPs), and inspected the influence of bio-nano Pd (0) on the direct electron transfer and phenol biodegradation. Scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM-EDX) showed that bio-nano Pd (0) (~10 nm) were evenly dispersed on the surface and in the periplasm of P. putida. With the incorporation of bio-nano Pd (0), the redox currents of bacteria in the cyclic voltammetry (CV) became higher and the oxidation current increased as the addition of lactate, while the highest increase rates of two electron transfer system (ETS) rates were 63...
June 8, 2018: Ecotoxicology and Environmental Safety
https://www.readbyqxmd.com/read/29890331/recombinant-production-of-a-chimeric-antimicrobial-peptide-in-e-coli-and-assessment-of-its-activity-against-some-avian-clinically-isolated-pathogens
#15
Abass Tanhaiean, Marjan Azghandi, Jamshid Razmyar, Elyass Mohammadi, Mohammad Hadi Sekhavati
Over the last decades, poultry industry faced to the rapid emergence of multidrug-resistant bacteria as a global concern. Antimicrobial peptide (AMPs) known as potential antibiotic alternative and were considered as a new antimicrobial agent. Current methods of production and purification of AMPs have several limitations such as: costly, time-consuming and killing the producing host cells in recombinant form. In the present study, a chimeric peptide derived from camel lactoferrin was produced in Escherichia coli periplasmic space using a pET-based expression system and its antibacterial activity was determined on some avian pathogens in vitro...
June 8, 2018: Microbial Pathogenesis
https://www.readbyqxmd.com/read/29886016/the-fapf-amyloid-secretion-transporter-possesses-an-atypical-asymmetric-coiled-coil
#16
Sarah L Rouse, Fisentzos Stylianou, H Y Grace Wu, Jamie-Lee Berry, Lee Sewell, R Marc L Morgan, Andrea C Sauerwein, Steve Matthews
Gram-negative bacteria possess specialised biogenesis machineries that facilitate the export of amyloid subunits, the fibres of which are key components of their biofilm matrix. The secretion of bacterial functional amyloid requires a specialised outer-membrane protein channel through which unfolded amyloid substrates are translocated. We previously reported the crystal structure of the membrane-spanning domain of the amyloid subunit transporter FapF from Pseudomonas. However, the structure of the periplasmic domain, which is essential for amyloid transport, is yet to be determined...
June 7, 2018: Journal of Molecular Biology
https://www.readbyqxmd.com/read/29885553/linear-gold-i-complex-with-tris-2-carboxyethyl-phosphine-tcep-selective-antitumor-activity-and-inertness-toward-sulfur-proteins
#17
S Q Gomes, L Vitoriano, E G R de Arruda, A L T G Ruiz, T Candido, J E de Carvalho, W R Lustri, C Abbehausen
The search for modulating ligand substitution reaction in gold complexes is essential to find new active metallo compounds for medical applications. In this work, a new linear and hydrosoluble goldI complex with tris-(2-carboxyethylphosphine) (AuTCEP). The two phosphines coordinate linearly to the metal as solved by single crystal X-ray diffraction. Complete spectroscopic characterization is also reported. In vitro growth inhibition (GI50 ) in a panel of nine tumorigenic and one non-tumorigenic cell lines demonstrated the complex is highly selective to ovarium adenocarcinoma (OVCAR-03) with GI50 of 3...
April 14, 2018: Journal of Inorganic Biochemistry
https://www.readbyqxmd.com/read/29882886/polyionic-tags-as-enhancers-of-protein-solubility-in-recombinant-protein-expression
#18
REVIEW
Vasiliki Paraskevopoulou, Franco H Falcone
Since the introduction of recombinant protein expression in the second half of the 1970s, the growth of the biopharmaceutical field has been rapid and protein therapeutics has come to the foreground. Biophysical and structural characterisation of recombinant proteins is the essential prerequisite for their successful development and commercialisation as therapeutics. Despite the challenges, including low protein solubility and inclusion body formation, prokaryotic host systems and particularly Escherichia coli , remain the system of choice for the initial attempt of production of previously unexpressed proteins...
May 23, 2018: Microorganisms
https://www.readbyqxmd.com/read/29879224/a-cell-based-infection-assay-identifies-efflux-pump-modulators-that-reduce-bacterial-intracellular-load
#19
Abigail L Reens, Amy L Crooks, Chih-Chia Su, Toni A Nagy, David L Reens, Jessica D Podoll, Madeline E Edwards, Edward W Yu, Corrella S Detweiler
Bacterial efflux pumps transport small molecules from the cytoplasm or periplasm outside the cell. Efflux pump activity is typically increased in multi-drug resistant (MDR) pathogens; chemicals that inhibit efflux pumps may have potential for antibiotic development. Using an in-cell screen, we identified three efflux pump modulators (EPMs) from a drug diversity library. The screening platform uses macrophages infected with the human Gram-negative pathogen Salmonella enterica (Salmonella) to identify small molecules that prevent bacterial replication or survival within the host environment...
June 7, 2018: PLoS Pathogens
https://www.readbyqxmd.com/read/29876306/nap-enzyme-recruitment-in-simultaneous-bioremediation-and-nanoparticles-synthesis
#20
Marwa Eltarahony, Sahar Zaki, Zeinab Kheiralla, Desouky Abd-El-Haleem
The periplasmic nitrate reductase enzyme (NAP) has become attractive catalyst, whose exploitation has emerged as one of the indispensable strategies toward environmentally benign applications. To achieve them efficiently and overcome the sensitivity of NAP in harsh environmental circumstances, the immobilization for denitrifying bacteria and NAP enzyme for simultaneous bioremediation and bionanoparticles synthesis was studied. NAP catalyzed NO3 - reduction at Vmax of 0.811 μM/min and Km of 14.02 mM. Concurrently, the immobilized MMT cells completely removed NO3 - upon 192 h with AgNPs synthesis ranging from 23...
June 2018: Biotechnology Reports
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