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Branwen M Hall, Elena B M Breidenstein, César de la Fuente-Núñez, Fany Reffuveille, Gina D Mawla, Robert E W Hancock, Tania A Baker
Caseinolytic peptidases (ClpPs) regulate diverse aspects of cellular physiology in bacteria. Some species have multiple ClpPs including opportunistic pathogen Pseudomonas aeruginosa in which there is an archetypical isoform, ClpP1, and a second isoform, ClpP2, about which little is known. Here we use phenotypic assays to investigate biological roles of ClpP1 and ClpP2 and biochemical assays to characterize purified ClpP1, ClpP2, ClpX and ClpA. Interestingly ClpP1 and ClpP2 have distinct intracellular roles for motility, pigment production, iron scavenging and biofilm formation...
November 14, 2016: Journal of Bacteriology
Piere Rodriguez-Aliaga, Luis Ramirez, Frank Kim, Carlos Bustamante, Andreas Martin
ATP-dependent proteases of the AAA+ family, including Escherichia coli ClpXP and the eukaryotic proteasome, contribute to maintenance of cellular proteostasis. ClpXP unfolds and translocates substrates into an internal degradation chamber, using cycles of alternating dwell and burst phases. The ClpX motor performs chemical transformations during the dwell and translocates the substrate in increments of 1-4 nm during the burst, but the processes occurring during these phases remain unknown. Here we characterized the complete mechanochemical cycle of ClpXP, showing that ADP release and ATP binding occur nonsequentially during the dwell, whereas ATP hydrolysis and phosphate release occur during the burst...
September 26, 2016: Nature Structural & Molecular Biology
Bobbi S Pritt, Laurel B Respicio-Kingry, Lynne M Sloan, Martin E Schriefer, Adam J Replogle, Jenna Bjork, Gongping Liu, Luke C Kingry, Paul S Mead, David F Neitzel, Elizabeth Schiffman, Diep K Hoang Johnson, Jeffrey P Davis, Susan M Paskewitz, David Boxrud, Alecia Deedon, Xia Lee, Tracy K Miller, Michelle A Feist, Christopher R Steward, Elitza S Theel, Robin Patel, Cole L Irish, Jeannine M Petersen
Lyme borreliosis (LB) is a multisystem disease caused by spirochetes in the Borrelia burgdorferi sensu lato (Bbsl) genospecies complex. We previously described a novel Borrelia species (type strain MN14-1420T) that causes LB among patients with exposures to ticks in the upper midwestern United States. Patients infected with the novel species demonstrated high levels of spirochetemia and differing clinical symptoms as compared to other Bbsl genospecies. The organism was detected from human specimens using polymerase chain reaction, microscopy, serology and culture...
August 24, 2016: International Journal of Systematic and Evolutionary Microbiology
Kristoffer T Bæk, Lisa Bowman, Charlotte Millership, Mia Dupont Søgaard, Volkhard Kaever, Pia Siljamäki, Kirsi Savijoki, Pekka Varmanen, Tuula A Nyman, Angelika Gründling, Dorte Frees
UNLABELLED: Lipoteichoic acid (LTA) is an important cell wall component of Gram-positive bacteria and a promising target for the development of vaccines and antimicrobial compounds against Staphylococcus aureus Here we demonstrate that mutations in the conditionally essential ltaS (LTA synthase) gene arise spontaneously in an S. aureus mutant lacking the ClpX chaperone. A wide variety of ltaS mutations were selected, and among these, a substantial portion resulted in premature stop codons and other changes predicted to abolish LtaS synthesis...
2016: MBio
Yoshiko Kubota, Kazumi Nomura, Yasutake Katoh, Rina Yamashita, Kiriko Kaneko, Kazumichi Furuyama
In eukaryotic cells, heme production is tightly controlled by heme itself through negative feedback-mediated regulation of nonspecific 5-aminolevulinate synthase (ALAS1), which is a rate-limiting enzyme for heme biosynthesis. However, the mechanism driving the heme-dependent degradation of the ALAS1 protein in mitochondria is largely unknown. In the current study, we provide evidence that the mitochondrial ATP-dependent protease ClpXP, which is a heteromultimer of CLPX and CLPP, is involved in the heme-dependent degradation of ALAS1 in mitochondria...
September 23, 2016: Journal of Biological Chemistry
Jae Ho Seo, Dayana B Rivadeneira, M Cecilia Caino, Young Chan Chae, David W Speicher, Hsin-Yao Tang, Valentina Vaira, Silvano Bosari, Alessandro Palleschi, Paolo Rampini, Andrew V Kossenkov, Lucia R Languino, Dario C Altieri
Mitochondria must buffer the risk of proteotoxic stress to preserve bioenergetics, but the role of these mechanisms in disease is poorly understood. Using a proteomics screen, we now show that the mitochondrial unfoldase-peptidase complex ClpXP associates with the oncoprotein survivin and the respiratory chain Complex II subunit succinate dehydrogenase B (SDHB) in mitochondria of tumor cells. Knockdown of ClpXP subunits ClpP or ClpX induces the accumulation of misfolded SDHB, impairing oxidative phosphorylation and ATP production while activating "stress" signals of 5' adenosine monophosphate-activated protein kinase (AMPK) phosphorylation and autophagy...
July 2016: PLoS Biology
A Trmčić, K Chauhan, D J Kent, R D Ralyea, N H Martin, K J Boor, M Wiedmann
Coliform detection in finished products, including cheese, has traditionally been used to indicate whether a given product has been manufactured under unsanitary conditions. As our understanding of the diversity of coliforms has improved, it is necessary to assess whether coliforms are a good indicator organism and whether coliform detection in cheese is associated with the presence of pathogens. The objective of this study was (1) to evaluate cheese available on the market for presence of coliforms and key pathogens, and (2) to characterize the coliforms present to assess their likely sources and public health relevance...
August 2016: Journal of Dairy Science
M A Veselova, Yu M Romanova, V A Lipasova, O A Koksharova, Yu V Zaitseva, M U Chernukha, A L Gintsburg, I A Khmel
In order to study the regulation of N-acyl-homoserine lactones synthesis (AHLs, the signal molecules of Quorum Sensing regulation) in Burkholderia cenocepacia strain 370 we obtained mutants with increased AHL production. One of the mutants, named BC-B6, was obtained by TnMod-RKm(r) plasposon mutagenesis. The plasposon insertion was located within the clpX gene encoding the ATPase subunit ClpX of the ClpXP protease. The mutation reduced bacterial virulence in mice intranasal infection. The results of proteomic analysis demonstrated that the expression of at least 19 proteins differed not less than 2-fold between the parental and mutant strains...
May 2016: Microbiological Research
Qiuhua Bao, Yuqin Song, Haiyan Xu, Jie Yu, Wenyi Zhang, Bilige Menghe, Heping Zhang, Zhihong Sun
Lactobacillus casei is a lactic acid bacterium used in manufacturing of many fermented food products. To investigate the genetic diversity and population biology of this food-related bacterium, 224 Lb. casei isolates and 5 reference isolates were examined by multilocus sequence typing (MLST). Among them, 224 Lb. casei isolates were isolated from homemade fermented foods, including naturally fermented dairy products, acidic gruel, and Sichuan pickles from 38 different regions in China and Mongolia. The MLST scheme was developed based on the analysis of 10 selected housekeeping genes (carB, clpX, dnaA, groEL, murE, pyrG, pheS, recA, rpoC, and uvrC)...
July 2016: Journal of Dairy Science
Korrie L Mack, James Shorter
Cells have evolved a sophisticated proteostasis network to ensure that proteins acquire and retain their native structure and function. Critical components of this network include molecular chaperones and protein disaggregases, which function to prevent and reverse deleterious protein misfolding. Nevertheless, proteostasis networks have limits, which when exceeded can have fatal consequences as in various neurodegenerative disorders, including Parkinson's disease and amyotrophic lateral sclerosis. A promising strategy is to engineer proteostasis networks to counter challenges presented by specific diseases or specific proteins...
2016: Frontiers in Molecular Biosciences
Alvaro J Amor, Karl R Schmitz, Jason K Sello, Tania A Baker, Robert T Sauer
The ClpXP protease assembles in a reaction in which an ATP-bound ring hexamer of ClpX binds to one or both heptameric rings of the ClpP peptidase. Contacts between ClpX IGF-loops and clefts on a ClpP ring stabilize the complex. How ClpXP stability is maintained during the ATP-hydrolysis cycle that powers mechanical unfolding and translocation of protein substrates is poorly understood. Here, we use a real-time kinetic assay to monitor the effects of nucleotides on the assembly and disassembly of ClpXP. When ATP is present, complexes containing single-chain ClpX assemble via an intermediate and remain intact until transferred into buffers containing ADP or no nucleotides...
June 17, 2016: ACS Chemical Biology
Monika S Buczek, Andrea L Cardenas Arevalo, Anuradha Janakiraman
The bacterial FtsZ-ring is an essential cytokinetic structure under tight spatiotemporal regulation. In Escherichia coli, FtsZ polymerization and assembly into the Z-ring is controlled on multiple levels through interactions with positive and negative regulators. Among these regulatory factors are ZapC, a Z-ring stabilizer, and the conserved protease ClpXP, which has been shown to degrade FtsZ protofilaments in preference to FtsZ monomers. Here we report that ZapC and ClpX interact in a protein-protein interaction assay, and that ZapC is degraded in a ClpXP-dependent manner in vivo...
June 2016: Microbiology
Yu-Tzu Lin, Jui-Chang Tsai, Tatsuo Yamamoto, Hsiao-Jan Chen, Wei-Chun Hung, Po-Ren Hsueh, Lee-Jene Teng
OBJECTIVES: Small colony variants (SCVs) of Staphylococcus aureus are associated with persistent and drug-resistant infections. We demonstrated for the first time the emergence of SCVs in a patient with vancomycin-intermediate S. aureus (VISA) infection during long-term treatment with daptomycin. METHODS: A 73-year-old man with septic arthritis was infected with VISA. The patient was treated with daptomycin; however, the patient remained infected with VISA, with continuous isolation of VISA from his blood during long-term treatment...
July 2016: Journal of Antimicrobial Chemotherapy
Kirsten Famulla, Peter Sass, Imran Malik, Tatos Akopian, Olga Kandror, Marina Alber, Berthold Hinzen, Helga Ruebsamen-Schaeff, Rainer Kalscheuer, Alfred L Goldberg, Heike Brötz-Oesterhelt
The Clp protease complex in Mycobacterium tuberculosis is unusual in its composition, functional importance and activation mechanism. Whilst most bacterial species contain a single ClpP protein that is dispensable for normal growth, mycobacteria have two ClpPs, ClpP1 and ClpP2, which are essential for viability and together form the ClpP1P2 tetradecamer. Acyldepsipeptide antibiotics of the ADEP class inhibit the growth of Gram-positive firmicutes by activating ClpP and causing unregulated protein degradation...
July 2016: Molecular Microbiology
Alexander L Greninger, Som S Chatterjee, Liana C Chan, Stephanie M Hamilton, Henry F Chambers, Charles Y Chiu
Fifth-generation cephalosporins, ceftobiprole and ceftaroline, are promising drugs for treatment of bacterial infections from methicillin-resistant Staphylococcus aureus (MRSA). These antibiotics are able to bind native PBP2a, the penicillin-binding protein encoded by the mecA resistance determinant that mediates broad class resistance to nearly all other beta-lactam antibiotics, at clinically achievable concentrations. Mechanisms of resistance to ceftaroline based on mecA mutations have been previously described...
2016: PloS One
Mi Li, Olga Kandror, Tatos Akopian, Poorva Dharkar, Alexander Wlodawer, Michael R Maurizi, Alfred L Goldberg
The ClpP protease complex and its regulatory ATPases, ClpC1 and ClpX, inMycobacterium tuberculosis(Mtb) are essential and, therefore, promising drug targets. TheMtbClpP protease consists of two heptameric rings, one composed of ClpP1 and the other of ClpP2 subunits. Formation of the enzymatically active ClpP1P2 complex requires binding of N-blocked dipeptide activators. We have found a new potent activator, benzoyl-leucine-leucine (Bz-LL), that binds with higher affinity and promotes 3-4-fold higher peptidase activity than previous activators...
April 1, 2016: Journal of Biological Chemistry
Yang Zhang, Michael R Maurizi
In human cells ClpP and ClpX are imported into the mitochondrial matrix, where they interact to form the ATP-dependent protease ClpXP and play a role in the mitochondrial unfolded protein response. We find that reducing the levels of mitochondrial ClpP or ClpX renders human cancer cells more sensitive to cisplatin, a widely used anti-cancer drug. Conversely, overexpression of HClpP desensitizes cells to cisplatin. Overexpression of inactive HClpP-S97A had no effect. Cisplatin resistance correlated with decreased cellular accumulation of cisplatin and decreased levels of diguanosine-cisplatin adducts in both mitochondrial and genomic DNA...
February 2016: Biochimica et Biophysica Acta
Adrian O Olivares, Tania A Baker, Robert T Sauer
To maintain protein homeostasis, AAA+ proteolytic machines degrade damaged and unneeded proteins in bacteria, archaea and eukaryotes. This process involves the ATP-dependent unfolding of a target protein and its subsequent translocation into a self-compartmentalized proteolytic chamber. Related AAA+ enzymes also disaggregate and remodel proteins. Recent structural and biochemical studies, in combination with direct visualization of unfolding and translocation in single-molecule experiments, have illuminated the molecular mechanisms behind these processes and suggest how remodelling of macromolecular complexes by AAA+ enzymes could occur without global denaturation...
January 2016: Nature Reviews. Microbiology
Axel Pahl, Markus Lakemeyer, Marie-Theres Vielberg, Mathias W Hackl, Jan Vomacka, Vadim S Korotkov, Martin L Stein, Christian Fetzer, Katrin Lorenz-Baath, Klaus Richter, Herbert Waldmann, Michael Groll, Stephan A Sieber
Caseinolytic protease P (ClpP) is an important regulator of Staphylococcus aureus pathogenesis. A high-throughput screening for inhibitors of ClpP peptidase activity led to the identification of the first non-covalent binder for this enzyme class. Co-crystallization of the small molecule with S. aureus ClpP revealed a novel binding mode: Because of the rotation of the conserved residue proline 125, ClpP is locked in a defined conformational state, which results in distortion of the catalytic triad and inhibition of the peptidase activity...
December 21, 2015: Angewandte Chemie
Haiyan Xu, Wenjun Liu, Wenyi Zhang, Jie Yu, Yuqin Song, Bilige Menhe, Heping Zhang, Zhihong Sun
BACKGROUND: Lactobacillus plantarum is a lactic acid bacterium (LAB) of considerable industrial interest since it has an important role in the production of fermented food. In the present study, the genetic diversity and population structure within 186 L. plantarum isolates was determined based on a novel MLST scheme employing eight housekeeping genes. These isolates had originated from different sources and geographic regions: 179 isolates were from our own culture collection and originated from China and Mongolia and seven isolates were type or reference isolates from other collections...
2015: BMC Microbiology
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