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https://www.readbyqxmd.com/read/29405518/contractile-injection-systems-of-bacteriophages-and-related-systems
#1
REVIEW
Nicholas M I Taylor, Mark J van Raaij, Petr G Leiman
Contractile tail bacteriophages, or myobacteriophages, use a sophisticated biomolecular structure to inject their genome into the bacterial host cell. This structure consists of a contractile sheath enveloping a rigid tube that is sharpened by a spike-shaped protein complex at its tip. The spike complex forms the centerpiece of a baseplate complex that terminates the sheath and the tube. The baseplate anchors the tail to the target cell membrane with the help of fibrous proteins emanating from it and triggers contraction of the sheath...
February 5, 2018: Molecular Microbiology
https://www.readbyqxmd.com/read/29209037/bacteriophage-t5-tail-tube-structure-suggests-a-trigger-mechanism-for-siphoviridae-dna-ejection
#2
Charles-Adrien Arnaud, Grégory Effantin, Corinne Vivès, Sylvain Engilberge, Maria Bacia, Pascale Boulanger, Eric Girard, Guy Schoehn, Cécile Breyton
The vast majority of phages, bacterial viruses, possess a tail ensuring host recognition, cell wall perforation and safe viral DNA transfer from the capsid to the host cytoplasm. Long flexible tails are formed from the tail tube protein (TTP) polymerised as hexameric rings around and stacked along the tape measure protein (TMP). Here, we report the crystal structure of T5 TTP pb6 at 2.2 Å resolution. Pb6 is unusual in forming a trimeric ring, although structure analysis reveals homology with all classical TTPs and related tube proteins of bacterial puncturing devices (type VI secretion system and R-pyocin)...
December 5, 2017: Nature Communications
https://www.readbyqxmd.com/read/29078392/exploitation-of-an-iron-transporter-for-bacterial-protein-antibiotic-import
#3
Paul White, Amar Joshi, Patrice Rassam, Nicholas G Housden, Renata Kaminska, Jonathan D Goult, Christina Redfield, Laura C McCaughey, Daniel Walker, Shabaz Mohammed, Colin Kleanthous
Unlike their descendants, mitochondria and plastids, bacteria do not have dedicated protein import systems. However, paradoxically, import of protein bacteriocins, the mechanisms of which are poorly understood, underpins competition among pathogenic and commensal bacteria alike. Here, using X-ray crystallography, isothermal titration calorimetry, confocal fluorescence microscopy, and in vivo photoactivatable cross-linking of stalled translocation intermediates, we demonstrate how the iron transporter FpvAI in the opportunistic pathogen Pseudomonas aeruginosa is hijacked to translocate the bacteriocin pyocin S2 (pyoS2) across the outer membrane (OM)...
November 7, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28973027/plant-expressed-pyocins-for-control-of-pseudomonas-aeruginosa
#4
Šarūnas Paškevičius, Urtė Starkevič, Audrius Misiūnas, Astra Vitkauskienė, Yuri Gleba, Aušra Ražanskienė
The emergence, persistence and spread of antibiotic-resistant human pathogenic bacteria heralds a growing global health crisis. Drug-resistant strains of gram-negative bacteria, such as Pseudomonas aeruginosa, are especially dangerous and the medical and economic burden they impose underscore the critical need for finding new antimicrobials. Recent studies have demonstrated that plant-expressed bacteriocins of the colicins family can be efficient antibacterials against all major enteropathogenic strains of E...
2017: PloS One
https://www.readbyqxmd.com/read/28818601/complete-genome-sequence-of-pseudomonas-antarctica-pamc-27494-a-bacteriocin-producing-psychrophile-isolated-from-antarctica
#5
Jaejin Lee, Yong-Joon Cho, Jae Young Yang, You-Jung Jung, Soon Gyu Hong, Ok-Sun Kim
Antimicrobial-producing, cold-adapted microorganisms have great potential for biotechnological applications in food, pharmaceutical, and cosmetic industries. Pseudomonas antarctica PAMC 27494, a psychrophile exhibiting antimicrobial activity, was isolated from an Antarctic freshwater sample. Here we report the complete genome of P. antarctica PAMC 27494. The strain contains a gene cluster encoding microcin B which inhibits DNA regulations by targeting the DNA gyrase. PAMC 27494 may produce R-type pyocins and also contains a complete set of proteins for the biosynthesis of adenosylcobalamin and possibly induces plant growth by supplying pyrroloquinoline quionone molecules...
August 14, 2017: Journal of Biotechnology
https://www.readbyqxmd.com/read/28715501/diversity-and-distribution-of-nuclease-bacteriocins-in-bacterial-genomes-revealed-using-hidden-markov-models
#6
Connor Sharp, James Bray, Nicholas G Housden, Martin C J Maiden, Colin Kleanthous
Bacteria exploit an arsenal of antimicrobial peptides and proteins to compete with each other. Three main competition systems have been described: type six secretion systems (T6SS); contact dependent inhibition (CDI); and bacteriocins. Unlike T6SS and CDI systems, bacteriocins do not require contact between bacteria but are diffusible toxins released into the environment. Identified almost a century ago, our understanding of bacteriocin distribution and prevalence in bacterial populations remains poor. In the case of protein bacteriocins, this is because of high levels of sequence diversity and difficulties in distinguishing their killing domains from those of other competition systems...
July 2017: PLoS Computational Biology
https://www.readbyqxmd.com/read/28687515/effect-of-a-pseudomonas-fluorescens-tailocin-against-phytopathogenic-xanthomonas-observed-by-atomic-force-microscopy
#7
Maricruz Fernandez, Agustina Godino, Analía Príncipe, Gustavo M Morales, Sonia Fischer
Phage tail-like bacteriocins, called tailocins, represent a class of protein complexes produced by a multitude of bacteria. Pseudomonas fluorescens SF4c, a strain isolated from wheat rhizosphere, produces a bacteriocin similar to phage tail-like pyocins of Pseudomonas aeruginosa. This tailocin has antimicrobial activity against several phytopathogenic strains of the genus Xanthomonas and Pseudomonas. In this work, the effect of the SF4c tailocin on the phytopathogenic strain X. axonopodis pv vesicatoria Xcv Bv5-4a was analyzed through Atomic Force Microscopy (AFM)...
July 5, 2017: Journal of Biotechnology
https://www.readbyqxmd.com/read/28665976/the-papi-1-pathogenicity-island-encoded-small-rna-pesa-influences-pseudomonas-aeruginosa-virulence-and-modulates-pyocin-s3-production
#8
Silvia Ferrara, Marilena Falcone, Raffaella Macchi, Alessandra Bragonzi, Daniela Girelli, Lisa Cariani, Cristina Cigana, Giovanni Bertoni
Small non-coding RNAs (sRNAs) are post-transcriptional regulators of gene expression that have been recognized as key contributors to bacterial virulence and pathogenic mechanisms. In this study, we characterized the sRNA PesA of the opportunistic human pathogen Pseudomonas aeruginosa. We show that PesA, which is transcribed within the pathogenicity island PAPI-1 of P. aeruginosa strain PA14, contributes to P. aeruginosa PA14 virulence. In fact, pesA gene deletion resulted in a less pathogenic strain, showing higher survival of cystic fibrosis human bronchial epithelial cells after infection...
2017: PloS One
https://www.readbyqxmd.com/read/28602424/using-force-to-punch-holes-mechanics-of-contractile-nanomachines
#9
REVIEW
Maximilian Brackmann, Sergey Nazarov, Jing Wang, Marek Basler
Using physical force to translocate macromolecules across a membrane has the advantage of being a universal solution independent of the properties of the target membrane. However, physically punching a stiff membrane is not a trivial task and three things are necessary for success: a sharp tip, a source of energy, and the ability to strongly bind to the target. In this review we describe the basic mechanism of membrane puncturing by contractile nanomachines with a focus on the T4 phage, R-type pyocin, and the bacterial Type VI secretion system (T6SS) based on recent studies of the structures and dynamics of their assembly...
June 8, 2017: Trends in Cell Biology
https://www.readbyqxmd.com/read/28446704/preservation-of-protein-expression-systems-at-elevated-temperatures-for-portable-therapeutic-production
#10
David K Karig, Seneca Bessling, Peter Thielen, Sherry Zhang, Joshua Wolfe
Many biotechnology capabilities are limited by stringent storage needs of reagents, largely prohibiting use outside of specialized laboratories. Focusing on a large class of protein-based biotechnology applications, we address this issue by developing a method for preserving cell-free protein expression systems for months above room temperature. Our approach realizes unprecedented long-term stability at elevated temperatures by leveraging the sugar alcohol trehalose, a simple, low-cost, open-air drying step, and strategic separation of reaction components during drying...
April 2017: Journal of the Royal Society, Interface
https://www.readbyqxmd.com/read/28285722/bacteriophage-sp6-encodes-a-second-tailspike-protein-that-recognizes-salmonella-enterica-serogroups-c2-and-c3
#11
Dana Gebhart, Steven R Williams, Dean Scholl
SP6 is a salmonella phage closely related to coliphage K1-5. K1-5 is notable in that it encodes two polysaccharide-degrading tailspike proteins, an endosialidase that allows it to infect E. coli K1, and a lyase that enables it to infect K5 strains. SP6 is similar to K1-5 except that it encodes a P22-like endorhamnosidase tailspike, gp46, allowing it to infect group B Salmonella. We show here that SP6 can also infect Salmonella serogroups C2 and C3 and that a mutation in a putative second tailspike, gp47, eliminates this specificity...
July 2017: Virology
https://www.readbyqxmd.com/read/28242657/tn6350-a-novel-transposon-carrying-pyocin-s8-genes-encoding-a-bacteriocin-with-activity-against-carbapenemase-producing-pseudomonas-aeruginosa
#12
Helena Turano, Fernando Gomes, Gesiele A Barros-Carvalho, Ralf Lopes, Louise Cerdeira, Luis E S Netto, Ana C Gales, Nilton Lincopan
A novel transposon belonging to the Tn3-like family was identified on the chromosome of a commensal strain of Pseudomonas aeruginosa sequence type 2343 (ET02). Tn6350 is 7,367 bp long and harbors eight open reading frames (ORFs), an ATPase (IS481 family), a transposase (DDE catalytic type), a Tn3 resolvase, three hypothetical proteins, and genes encoding the new pyocin S8 with its immunity protein. We show that pyocin S8 displays activity against carbapenemase-producing P. aeruginosa, including IMP-1, SPM-1, VIM-1, GES-5, and KPC-2 producers...
May 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/28223456/a-natural-chimeric-pseudomonas-bacteriocin-with-novel-pore-forming-activity-parasitizes-the-ferrichrome-transporter
#13
Maarten G K Ghequire, Lieselore Kemland, Ernesto Anoz-Carbonell, Susan K Buchanan, René De Mot
Modular bacteriocins represent a major group of secreted protein toxins with a narrow spectrum of activity, involved in interference competition between Gram-negative bacteria. These antibacterial proteins include a domain for binding to the target cell and a toxin module at the carboxy terminus. Self-inhibition of producers is provided by coexpression of linked immunity genes that transiently inhibit the toxin's activity through formation of bacteriocin-immunity complexes or by insertion in the inner membrane, depending on the type of toxin module...
February 21, 2017: MBio
https://www.readbyqxmd.com/read/28060574/the-hcp-proteins-fused-with-diverse-extended-toxin-domains-represent-a-novel-pattern-of-antibacterial-effectors-in-type-vi-secretion-systems
#14
Jiale Ma, Zihao Pan, Jinhu Huang, Min Sun, Chengping Lu, Huochun Yao
The type VI secretion system (T6SS) is a widespread molecular weapon deployed by many bacterial species to target eukaryotic host cells or rival bacteria. Using a dynamic injection mechanism, diverse effectors can be delivered by T6SS directly into recipient cells. Here, we report a new family of T6SS effectors encoded by extended Hcps carrying diverse toxin domains. Bioinformatic analyses revealed that these Hcps with C-terminal extension toxins, designated as Hcp-ET, exist widely in the Enterobacteriaceae...
January 6, 2017: Virulence
https://www.readbyqxmd.com/read/28052848/pseudomonas-aeruginosa-oligoribonuclease-contributes-to-tolerance-to-ciprofloxacin-by-regulating-pyocin-biosynthesis
#15
Fei Chen, Gukui Chen, Yiwei Liu, Yongxin Jin, Zhihui Cheng, Yang Liu, Liang Yang, Shouguang Jin, Weihui Wu
Bacterial oligoribonuclease (Orn) is a conserved 3'-to-5' exonuclease. In Pseudomonas aeruginosa, it has been demonstrated that Orn plays a major role in the hydrolysis of pGpG, which is required for cyclic-di-GMP homeostasis. Meanwhile, Orn is involved in the degradation of nanoRNAs, which can alter global gene expression by serving as transcription initiation primers. Previously, we found that Orn is required for the type III secretion system and pathogenesis of P. aeruginosa, indicating a role of Orn in the bacterial response to environmental stimuli...
March 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/27457717/f-type-bacteriocins-of-listeria-monocytogenes-a-new-class-of-phage-tail-like-structures-reveals-broad-parallel-coevolution-between-tailed-bacteriophages-and-high-molecular-weight-bacteriocins
#16
Grace Lee, Urmi Chakraborty, Dana Gebhart, Gregory R Govoni, Z Hong Zhou, Dean Scholl
UNLABELLED: Listeria monocytogenes is a significant foodborne human pathogen that can cause severe disease in certain high-risk individuals. L. monocytogenes is known to produce high-molecular-weight, phage tail-like bacteriocins, or "monocins," upon induction of the SOS system. In this work, we purified and characterized monocins and found them to be a new class of F-type bacteriocins. The L. monocytogenes monocin genetic locus was cloned and expressed in Bacillus subtilis, producing specifically targeted bactericidal particles...
October 15, 2016: Journal of Bacteriology
https://www.readbyqxmd.com/read/27444885/efficacy-of-species-specific-protein-antibiotics-in-a-murine-model-of-acute-pseudomonas-aeruginosa-lung-infection
#17
Laura C McCaughey, Neil D Ritchie, Gillian R Douce, Thomas J Evans, Daniel Walker
Protein antibiotics, known as bacteriocins, are widely produced by bacteria for intraspecies competition. The potency and targeted action of bacteriocins suggests that they could be developed into clinically useful antibiotics against highly drug resistant Gram-negative pathogens for which there are few therapeutic options. Here we show that Pseudomonas aeruginosa specific bacteriocins, known as pyocins, show strong efficacy in a murine model of P. aeruginosa lung infection, with the concentration of pyocin S5 required to afford protection from a lethal infection at least 100-fold lower than the most commonly used inhaled antibiotic tobramycin...
July 22, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27402794/structural-and-biophysical-analysis-of-nuclease-protein-antibiotics
#18
Alexander Klein, Justyna Aleksandra Wojdyla, Amar Joshi, Inokentijs Josts, Laura C McCaughey, Nicholas G Housden, Renata Kaminska, Olwyn Byron, Daniel Walker, Colin Kleanthous
Protein antibiotics (bacteriocins) are a large and diverse family of multidomain toxins that kill specific Gram-negative bacteria during intraspecies competition for resources. Our understanding of the mechanism of import of such potent toxins has increased significantly in recent years, especially with the reporting of several structures of bacteriocin domains. Less well understood is the structural biochemistry of intact bacteriocins and how these compare across bacterial species. Here, we focus on endonuclease (DNase) bacteriocins that target the genomes of Escherichia coli and Pseudomonas aeruginosa, known as E-type colicins and S-type pyocins, respectively, bound to their specific immunity (Im) proteins...
September 15, 2016: Biochemical Journal
https://www.readbyqxmd.com/read/27252387/discovery-characterization-and-in%C3%A2-vivo-activity-of-pyocin-sd2-a-protein-antibiotic-from-pseudomonas-aeruginosa
#19
Laura C McCaughey, Inokentijs Josts, Rhys Grinter, Paul White, Olwyn Byron, Nicholas P Tucker, Jacqueline M Matthews, Colin Kleanthous, Cynthia B Whitchurch, Daniel Walker
Increasing rates of antibiotic resistance among Gram-negative pathogens such as Pseudomonas aeruginosa means alternative approaches to antibiotic development are urgently required. Pyocins, produced by P. aeruginosa for intraspecies competition, are highly potent protein antibiotics known to actively translocate across the outer membrane of P. aeruginosa. Understanding and exploiting the mechanisms by which pyocins target, penetrate and kill P. aeruginosa is a promising approach to antibiotic development. In this work we show the therapeutic potential of a newly identified tRNase pyocin, pyocin SD2, by demonstrating its activity in vivo in a murine model of P...
August 1, 2016: Biochemical Journal
https://www.readbyqxmd.com/read/27193680/structure-of-the-t4-baseplate-and-its-function-in-triggering-sheath-contraction
#20
Nicholas M I Taylor, Nikolai S Prokhorov, Ricardo C Guerrero-Ferreira, Mikhail M Shneider, Christopher Browning, Kenneth N Goldie, Henning Stahlberg, Petr G Leiman
Several systems, including contractile tail bacteriophages, the type VI secretion system and R-type pyocins, use a multiprotein tubular apparatus to attach to and penetrate host cell membranes. This macromolecular machine resembles a stretched, coiled spring (or sheath) wound around a rigid tube with a spike-shaped protein at its tip. A baseplate structure, which is arguably the most complex part of this assembly, relays the contraction signal to the sheath. Here we present the atomic structure of the approximately 6-megadalton bacteriophage T4 baseplate in its pre- and post-host attachment states and explain the events that lead to sheath contraction in atomic detail...
May 19, 2016: Nature
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