LIVIVO - The Search Portal for Life Sciences

zur deutschen Oberfläche wechseln
Advanced search

Search results

Result 1 - 10 of total 15

Search options

  1. Article: Adding a polyphenol-rich fiber bundle to food impacts the gastrointestinal microbiome and metabolome in dogs.

    Fritsch, Dale A / Jackson, Matthew I / Wernimont, Susan M / Feld, Geoffrey K / Badri, Dayakar V / Brejda, John J / Cochrane, Chun-Yen / Gross, Kathy L

    Frontiers in veterinary science

    2023  Volume 9, Page(s) 1039032

    Abstract: Introduction: Pet foods fortified with fermentable fibers are often indicated for dogs with gastrointestinal conditions to improve gut health through the production of beneficial post-biotics by the pet's microbiome.: Methods: To evaluate the ... ...

    Abstract Introduction: Pet foods fortified with fermentable fibers are often indicated for dogs with gastrointestinal conditions to improve gut health through the production of beneficial post-biotics by the pet's microbiome.
    Methods: To evaluate the therapeutic underpinnings of pre-biotic fiber enrichment, we compared the fecal microbiome, the fecal metabolome, and the serum metabolome of 39 adult dogs with well-managed chronic gastroenteritis/enteritis (CGE) and healthy matched controls. The foods tested included a test food (TF1) containing a novel pre-biotic fiber bundle, a control food (CF) lacking the fiber bundle, and a commercially available therapeutic food (TF2) indicated for managing fiber-responsive conditions. In this crossover study, all dogs consumed CF for a 4-week wash-in period, were randomized to either TF1 or TF2 and fed for 4 weeks, were fed CF for a 4-week washout period, and then received the other test food for 4 weeks.
    Results: Meaningful differences were not observed between the healthy and CGE dogs in response to the pre-biotic fiber bundle relative to CF. Both TF1 and TF2 improved stool scores compared to CF. TF1-fed dogs showed reduced body weight and fecal ash content compared to either CF or TF2, while stools of TF2-fed dogs showed higher pH and lower moisture content vs. TF1. TF1 consumption also resulted in unique fecal and systemic metabolic signatures compared to CF and TF2. TF1-fed dogs showed suppressed signals of fecal bacterial putrefactive metabolism compared to either CF or TF2 and increased saccharolytic signatures compared to TF2. A functional analysis of fecal tryptophan metabolism indicated reductions in fecal kynurenine and indole pathway metabolites with TF1. Among the three foods, TF1 uniquely increased fecal polyphenols and the resulting post-biotics. Compared to CF, consumption of TF1 largely reduced fecal levels of endocannabinoid-like metabolites and sphingolipids while increasing both fecal and circulating polyunsaturated fatty acid profiles, suggesting that TF1 may have modulated gastrointestinal inflammation and motility. Stools of TF1-fed dogs showed reductions in phospholipid profiles, suggesting fiber-dependent changes to colonic mucosal structure.
    Discussion: These findings indicate that the use of a specific pre-biotic fiber bundle may be beneficial in healthy dogs and in dogs with CGE.
    Language English
    Publishing date 2023-01-20
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2834243-4
    ISSN 2297-1769
    ISSN 2297-1769
    DOI 10.3389/fvets.2022.1039032
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  2. Article ; Online: Microbiome function underpins the efficacy of a fiber-supplemented dietary intervention in dogs with chronic large bowel diarrhea

    Fritsch, Dale A. / Jackson, Matthew I. / Wernimont, Susan M. / Feld, Geoffrey K. / MacLeay, Jennifer M. / Brejda, John J. / Cochrane, Chun-Yen / Gross, Kathy L.

    BMC Vet Res. 2022 Dec., v. 18, no. 1 p.245-245

    2022  

    Abstract: BACKGROUND: Chronic large bowel diarrhea is a common occurrence in pet dogs. While nutritional intervention is considered the primary therapy, the metabolic and gut microfloral effects of fiber and polyphenol-enriched therapeutic foods are poorly ... ...

    Abstract BACKGROUND: Chronic large bowel diarrhea is a common occurrence in pet dogs. While nutritional intervention is considered the primary therapy, the metabolic and gut microfloral effects of fiber and polyphenol-enriched therapeutic foods are poorly understood. METHODS: This prospective clinical study enrolled 31 adult dogs from private veterinary practices with chronic, active large bowel diarrhea. Enrolled dogs received a complete and balanced dry therapeutic food containing a proprietary fiber bundle for 56 days. Metagenomic and metabolomic profiling were performed on fecal samples at Days 1, 2, 3, 14, 28, and 56; metabolomic analysis was conducted on serum samples taken at Days 1, 2, 3, 28, and 56. RESULTS: The dietary intervention improved clinical signs and had a clear effect on the gut microfloral metabolic output of canines with chronic diarrhea, shifting gut metabolism from a predominantly proteolytic to saccharolytic fermentative state. Microbial metabolism of tryptophan to beneficial indole postbiotics and the conversion of plant-derived phenolics into bioavailable postbiotics were observed. The intervention altered the endocannabinoid, polyunsaturated fatty acid, and sphingolipid profiles, suggesting a modulation in gastrointestinal inflammation. Changes in membrane phospholipid and collagen signatures were indicative of improved gut function and possible alleviation of the pathophysiology related to chronic diarrhea. CONCLUSIONS: In dogs with chronic diarrhea, feeding specific dietary fibers increased gut saccharolysis and bioavailable phenolic and indole-related compounds, while suppressing putrefaction. These changes were associated with improved markers of gut inflammation and stool quality.
    Keywords adults ; bioavailability ; blood serum ; cannabinoids ; collagen ; diarrhea ; dietetic foods ; gastrointestinal system ; indoles ; inflammation ; metabolism ; metabolomics ; metagenomics ; microbiome ; nutritional intervention ; pathophysiology ; phospholipids ; polyunsaturated fatty acids ; proteolysis ; sphingolipids ; tryptophan
    Language English
    Dates of publication 2022-12
    Size p. 245.
    Publishing place BioMed Central
    Document type Article ; Online
    ZDB-ID 2191675-5
    ISSN 1746-6148
    ISSN 1746-6148
    DOI 10.1186/s12917-022-03315-3
    Database NAL-Catalogue (AGRICOLA)

    More links

    Kategorien

  3. Article ; Online: Enabling membrane protein structure and dynamics with X-ray free electron lasers.

    Feld, Geoffrey K / Frank, Matthias

    Current opinion in structural biology

    2014  Volume 27, Page(s) 69–78

    Abstract: Determining the three-dimensional structures and dynamics of membrane proteins remains one of the great challenges of modern biology. The recent availability of X-ray free electron laser (XFEL) light sources has opened the door to a new and revolutionary ...

    Abstract Determining the three-dimensional structures and dynamics of membrane proteins remains one of the great challenges of modern biology. The recent availability of X-ray free electron laser (XFEL) light sources has opened the door to a new and revolutionary approach to performing X-ray analysis of these important biomolecules. Recent advances in sample delivery, data reduction, and phasing have enabled the high-resolution structural probing of membrane proteins at room temperature. While considerable challenges remain, the recent developments described in this review may ultimately provide structural biologists with powerful tools for obtaining unprecedented atomic-scale and dynamic visualization of membrane proteins at near-physiological conditions.
    MeSH term(s) Crystallography, X-Ray ; Electrons ; Humans ; Lasers ; Membrane Proteins/chemistry ; Membrane Proteins/metabolism ; Molecular Imaging/methods ; X-Rays
    Chemical Substances Membrane Proteins
    Language English
    Publishing date 2014-08
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, Non-P.H.S. ; Review
    ZDB-ID 1068353-7
    ISSN 1879-033X ; 0959-440X
    ISSN (online) 1879-033X
    ISSN 0959-440X
    DOI 10.1016/j.sbi.2014.05.002
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  4. Article ; Online: Microbiome function underpins the efficacy of a fiber-supplemented dietary intervention in dogs with chronic large bowel diarrhea.

    Fritsch, Dale A / Jackson, Matthew I / Wernimont, Susan M / Feld, Geoffrey K / MacLeay, Jennifer M / Brejda, John J / Cochrane, Chun-Yen / Gross, Kathy L

    BMC veterinary research

    2022  Volume 18, Issue 1, Page(s) 245

    Abstract: Background: Chronic large bowel diarrhea is a common occurrence in pet dogs. While nutritional intervention is considered the primary therapy, the metabolic and gut microfloral effects of fiber and polyphenol-enriched therapeutic foods are poorly ... ...

    Abstract Background: Chronic large bowel diarrhea is a common occurrence in pet dogs. While nutritional intervention is considered the primary therapy, the metabolic and gut microfloral effects of fiber and polyphenol-enriched therapeutic foods are poorly understood.
    Methods: This prospective clinical study enrolled 31 adult dogs from private veterinary practices with chronic, active large bowel diarrhea. Enrolled dogs received a complete and balanced dry therapeutic food containing a proprietary fiber bundle for 56 days. Metagenomic and metabolomic profiling were performed on fecal samples at Days 1, 2, 3, 14, 28, and 56; metabolomic analysis was conducted on serum samples taken at Days 1, 2, 3, 28, and 56.
    Results: The dietary intervention improved clinical signs and had a clear effect on the gut microfloral metabolic output of canines with chronic diarrhea, shifting gut metabolism from a predominantly proteolytic to saccharolytic fermentative state. Microbial metabolism of tryptophan to beneficial indole postbiotics and the conversion of plant-derived phenolics into bioavailable postbiotics were observed. The intervention altered the endocannabinoid, polyunsaturated fatty acid, and sphingolipid profiles, suggesting a modulation in gastrointestinal inflammation. Changes in membrane phospholipid and collagen signatures were indicative of improved gut function and possible alleviation of the pathophysiology related to chronic diarrhea.
    Conclusions: In dogs with chronic diarrhea, feeding specific dietary fibers increased gut saccharolysis and bioavailable phenolic and indole-related compounds, while suppressing putrefaction. These changes were associated with improved markers of gut inflammation and stool quality.
    MeSH term(s) Animals ; Diarrhea/veterinary ; Diet/veterinary ; Dietary Fiber/therapeutic use ; Dog Diseases/drug therapy ; Dogs ; Feces ; Indoles ; Inflammation/veterinary ; Microbiota ; Prospective Studies
    Chemical Substances Dietary Fiber ; Indoles
    Language English
    Publishing date 2022-06-24
    Publishing country England
    Document type Journal Article
    ZDB-ID 2191675-5
    ISSN 1746-6148 ; 1746-6148
    ISSN (online) 1746-6148
    ISSN 1746-6148
    DOI 10.1186/s12917-022-03315-3
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  5. Article ; Online: Structure of the sirtuin-linked macrodomain SAV0325 from Staphylococcus aureus.

    Appel, C Denise / Feld, Geoffrey K / Wallace, Bret D / Williams, R Scott

    Protein science : a publication of the Protein Society

    2016  Volume 25, Issue 9, Page(s) 1682–1691

    Abstract: Cells use the post-translational modification ADP-ribosylation to control a host of biological activities. In some pathogenic bacteria, an operon-encoded mono-ADP-ribosylation cycle mediates response to host-induced oxidative stress. In this system, ... ...

    Abstract Cells use the post-translational modification ADP-ribosylation to control a host of biological activities. In some pathogenic bacteria, an operon-encoded mono-ADP-ribosylation cycle mediates response to host-induced oxidative stress. In this system, reversible mono ADP-ribosylation of a lipoylated target protein represses oxidative stress response. An NAD(+) -dependent sirtuin catalyzes the single ADP-ribose (ADPr) addition, while a linked macrodomain-containing protein removes the ADPr. Here we report the crystal structure of the sitruin-linked macrodomain protein from Staphylococcus aureus, SauMacro (also known as SAV0325) to 1.75-Å resolution. The monomeric SauMacro bears a previously unidentified Zn(2+) -binding site that putatively aids in substrate recognition and catalysis. An amino-terminal three-helix bundle motif unique to this class of macrodomain proteins provides a structural scaffold for the Zn(2+) site. Structural features of the enzyme further indicate a cleft proximal to the Zn(2+) binding site appears well suited for ADPr binding, while a deep hydrophobic channel in the protein core is suitable for binding the lipoate of the lipoylated protein target.
    MeSH term(s) Bacterial Proteins/chemistry ; Crystallography, X-Ray ; Protein Domains ; Sirtuins/chemistry ; Staphylococcus aureus/chemistry ; Zinc/chemistry
    Chemical Substances Bacterial Proteins ; Sirtuins (EC 3.5.1.-) ; Zinc (J41CSQ7QDS)
    Keywords covid19
    Language English
    Publishing date 2016-07-07
    Publishing country United States
    Document type Journal Article ; Research Support, U.S. Gov't, Non-P.H.S. ; Research Support, N.I.H., Intramural
    ZDB-ID 1106283-6
    ISSN 1469-896X ; 0961-8368
    ISSN (online) 1469-896X
    ISSN 0961-8368
    DOI 10.1002/pro.2974
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  6. Article ; Online: Ratcheting up protein translocation with anthrax toxin.

    Feld, Geoffrey K / Brown, Michael J / Krantz, Bryan A

    Protein science : a publication of the Protein Society

    2012  Volume 21, Issue 5, Page(s) 606–624

    Abstract: Energy-consuming nanomachines catalyze the directed movement of biopolymers in the cell. They are found both dissolved in the aqueous cytosol as well as embedded in lipid bilayers. Inquiries into the molecular mechanism of nanomachine-catalyzed ... ...

    Abstract Energy-consuming nanomachines catalyze the directed movement of biopolymers in the cell. They are found both dissolved in the aqueous cytosol as well as embedded in lipid bilayers. Inquiries into the molecular mechanism of nanomachine-catalyzed biopolymer transport have revealed that these machines are equipped with molecular parts, including adjustable clamps, levers, and adaptors, which interact favorably with substrate polypeptides. Biological nanomachines that catalyze protein transport, known as translocases, often require that their substrate proteins unfold before translocation. An unstructured protein chain is likely entropically challenging to bind, push, or pull in a directional manner, especially in a way that produces an unfolding force. A number of ingenious solutions to this problem are now evident in the anthrax toxin system, a model used to study protein translocation. Here we highlight molecular ratchets and current research on anthrax toxin translocation. A picture is emerging of proton-gradient-driven anthrax toxin translocation, and its associated ratchet mechanism likely applies broadly to other systems. We suggest a cyclical thermodynamic order-to-disorder mechanism (akin to a heat-engine cycle) is central to underlying protein translocation: peptide substrates nonspecifically bind to molecular clamps, which possess adjustable affinities; polypeptide substrates compress into helical structures; these clamps undergo proton-gated switching; and the substrate subsequently expands regaining its unfolded state conformational entropy upon translocation.
    MeSH term(s) Antigens, Bacterial/chemistry ; Antigens, Bacterial/metabolism ; Bacterial Toxins/chemistry ; Bacterial Toxins/metabolism ; Models, Molecular ; Nanotechnology ; Peptidyl Transferases/chemistry ; Peptidyl Transferases/metabolism ; Protein Transport ; Protein Unfolding ; Thermodynamics
    Chemical Substances Antigens, Bacterial ; Bacterial Toxins ; anthrax toxin ; Peptidyl Transferases (EC 2.3.2.12)
    Language English
    Publishing date 2012-03-30
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Review
    ZDB-ID 1106283-6
    ISSN 1469-896X ; 0961-8368
    ISSN (online) 1469-896X
    ISSN 0961-8368
    DOI 10.1002/pro.2052
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  7. Article: Domain Flexibility Modulates the Heterogeneous Assembly Mechanism of Anthrax Toxin Protective Antigen

    Feld, Geoffrey K / Kintzer, Alexander F / Tang, Iok I / Thoren, Katie L / Krantz, Bryan A

    Journal of molecular biology. 2012 Jan. 6, v. 415, no. 1

    2012  

    Abstract: The three protein components of anthrax toxin are nontoxic individually, but they form active holotoxin complexes upon assembly. The role of the protective antigen (PA) component of the toxin is to deliver two other enzyme components, lethal factor and ... ...

    Abstract The three protein components of anthrax toxin are nontoxic individually, but they form active holotoxin complexes upon assembly. The role of the protective antigen (PA) component of the toxin is to deliver two other enzyme components, lethal factor and edema factor, across the plasma membrane and into the cytoplasm of target cells. PA is produced as a proprotein, which must be proteolytically activated; generally, cell surface activation is mediated by a furin family protease. Activated PA can then assemble into one of two noninterconverting oligomers, a homoheptamer and a homooctamer, which have unique properties. Herein we describe molecular determinants that influence the stoichiometry of PA in toxin complexes. By tethering PA domain 4 (D4) to domain 2 with two different-length cross-links, we can control the relative proportions of PA heptamers and octamers. The longer cross-link favors octamer formation, whereas the shorter one favors formation of the heptamer. X-ray crystal structures of PA (up to 1.45 Å resolution), including these cross-linked PA constructs, reveal that a hinge-like movement of D4 correlates with the relative preference for each oligomeric architecture. Furthermore, we report the conformation of the flexible loop containing the furin cleavage site and show that, for efficient processing, the furin site cannot be moved ∼5 or 6 residues within the loop. We propose that there are different orientations of D4 relative to the main body of PA that favor the formation of either the heptamer or the octamer.
    Keywords X-ray diffraction ; anthrax ; antigens ; crosslinking ; cytoplasm ; edema ; plasma membrane ; proteinases ; stoichiometry
    Language English
    Dates of publication 2012-0106
    Size p. 159-174.
    Publishing place Elsevier Ltd
    Document type Article
    ZDB-ID 80229-3
    ISSN 1089-8638 ; 0022-2836
    ISSN (online) 1089-8638
    ISSN 0022-2836
    DOI 10.1016/j.jmb.2011.10.035
    Database NAL-Catalogue (AGRICOLA)

    More links

    Kategorien

  8. Article ; Online: Domain flexibility modulates the heterogeneous assembly mechanism of anthrax toxin protective antigen.

    Feld, Geoffrey K / Kintzer, Alexander F / Tang, Iok I / Thoren, Katie L / Krantz, Bryan A

    Journal of molecular biology

    2011  Volume 415, Issue 1, Page(s) 159–174

    Abstract: The three protein components of anthrax toxin are nontoxic individually, but they form active holotoxin complexes upon assembly. The role of the protective antigen (PA) component of the toxin is to deliver two other enzyme components, lethal factor and ... ...

    Abstract The three protein components of anthrax toxin are nontoxic individually, but they form active holotoxin complexes upon assembly. The role of the protective antigen (PA) component of the toxin is to deliver two other enzyme components, lethal factor and edema factor, across the plasma membrane and into the cytoplasm of target cells. PA is produced as a proprotein, which must be proteolytically activated; generally, cell surface activation is mediated by a furin family protease. Activated PA can then assemble into one of two noninterconverting oligomers, a homoheptamer and a homooctamer, which have unique properties. Herein we describe molecular determinants that influence the stoichiometry of PA in toxin complexes. By tethering PA domain 4 (D4) to domain 2 with two different-length cross-links, we can control the relative proportions of PA heptamers and octamers. The longer cross-link favors octamer formation, whereas the shorter one favors formation of the heptamer. X-ray crystal structures of PA (up to 1.45 Å resolution), including these cross-linked PA constructs, reveal that a hinge-like movement of D4 correlates with the relative preference for each oligomeric architecture. Furthermore, we report the conformation of the flexible loop containing the furin cleavage site and show that, for efficient processing, the furin site cannot be moved ~5 or 6 residues within the loop. We propose that there are different orientations of D4 relative to the main body of PA that favor the formation of either the heptamer or the octamer.
    MeSH term(s) Antigens, Bacterial/chemistry ; Antigens, Bacterial/metabolism ; Bacillus anthracis/metabolism ; Bacterial Toxins/chemistry ; Bacterial Toxins/metabolism ; Binding Sites ; Cell Membrane/metabolism ; Crystallography, X-Ray/methods ; Cytoplasm/metabolism ; Furin/metabolism ; Models, Molecular ; Protein Structure, Secondary ; Protein Structure, Tertiary
    Chemical Substances Antigens, Bacterial ; Bacterial Toxins ; anthrax toxin ; Furin (EC 3.4.21.75)
    Language English
    Publishing date 2011-10-31
    Publishing country Netherlands
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 80229-3
    ISSN 1089-8638 ; 0022-2836
    ISSN (online) 1089-8638
    ISSN 0022-2836
    DOI 10.1016/j.jmb.2011.10.035
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  9. Article ; Online: Supercharging protein complexes from aqueous solution disrupts their native conformations.

    Sterling, Harry J / Kintzer, Alexander F / Feld, Geoffrey K / Cassou, Catherine A / Krantz, Bryan A / Williams, Evan R

    Journal of the American Society for Mass Spectrometry

    2011  Volume 23, Issue 2, Page(s) 191–200

    Abstract: The effects of aqueous solution supercharging on the solution- and gas-phase structures of two protein complexes were investigated using traveling-wave ion mobility-mass spectrometry (TWIMS-MS). Low initial concentrations of m-nitrobenzyl alcohol (m-NBA) ...

    Abstract The effects of aqueous solution supercharging on the solution- and gas-phase structures of two protein complexes were investigated using traveling-wave ion mobility-mass spectrometry (TWIMS-MS). Low initial concentrations of m-nitrobenzyl alcohol (m-NBA) in the electrospray ionization (ESI) solution can effectively increase the charge of concanavalin A dimers and tetramers, but at higher m-NBA concentrations, the increases in charge are accompanied by solution-phase dissociation of the dimers and up to a ~22% increase in the collision cross section (CCS) of the tetramers. With just 0.8% m-NBA added to the ESI solution of a ~630 kDa anthrax toxin octamer complex, the average charge is increased by only ~4% compared with the "native" complex, but it is sufficiently destabilized so that extensive gas-phase fragmentation occurs in the relatively high pressure regions of the TWIMS device. Anthrax toxin complexes exist in either a prechannel or a transmembrane channel state. With m-NBA, the prechannel state of the complex has the same CCS/charge ratio in the gas phase as the transmembrane channel state of the same complex formed without m-NBA, yet undergoes extensive dissociation, indicating that destabilization from supercharging occurs in the ESI droplet prior to ion formation and is not a result of Coulombic destabilization in the gas phase as a result of higher charging. These results demonstrate that the supercharging of large protein complexes is the result of conformational changes induced by the reagents in the ESI droplets, where enrichment of the supercharging reagent during droplet evaporation occurs.
    MeSH term(s) Acetates/chemistry ; Antigens, Bacterial/chemistry ; Bacterial Toxins/chemistry ; Benzyl Alcohols/chemistry ; Concanavalin A/chemistry ; Gases/chemistry ; Hydrogen-Ion Concentration ; Ions ; Models, Molecular ; Osmolar Concentration ; Protein Conformation ; Protein Subunits/chemistry ; Protein Unfolding ; Proteins/chemistry ; Spectrometry, Mass, Electrospray Ionization/methods ; Static Electricity
    Chemical Substances Acetates ; Antigens, Bacterial ; Bacterial Toxins ; Benzyl Alcohols ; Gases ; Ions ; Protein Subunits ; Proteins ; anthrax toxin ; Concanavalin A (11028-71-0) ; 3-nitrobenzyl alcohol (F829X990IV) ; ammonium acetate (RRE756S6Q2)
    Language English
    Publishing date 2011-12-13
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 1073671-2
    ISSN 1879-1123 ; 1044-0305
    ISSN (online) 1879-1123
    ISSN 1044-0305
    DOI 10.1007/s13361-011-0301-y
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  10. Article ; Online: Structure and function of REP34 implicates carboxypeptidase activity in Francisella tularensis host cell invasion.

    Feld, Geoffrey K / El-Etr, Sahar / Corzett, Michele H / Hunter, Mark S / Belhocine, Kamila / Monack, Denise M / Frank, Matthias / Segelke, Brent W / Rasley, Amy

    The Journal of biological chemistry

    2014  Volume 289, Issue 44, Page(s) 30668–30679

    Abstract: Francisella tularensis is the etiological agent of tularemia, or rabbit fever. Although F. tularensis is a recognized biothreat agent with broad and expanding geographical range, its mechanism of infection and environmental persistence remain poorly ... ...

    Abstract Francisella tularensis is the etiological agent of tularemia, or rabbit fever. Although F. tularensis is a recognized biothreat agent with broad and expanding geographical range, its mechanism of infection and environmental persistence remain poorly understood. Previously, we identified seven F. tularensis proteins that induce a rapid encystment phenotype (REP) in the free-living amoeba, Acanthamoeba castellanii. Encystment is essential to the pathogen's long term intracellular survival in the amoeba. Here, we characterize the cellular and molecular function of REP34, a REP protein with a mass of 34 kDa. A REP34 knock-out strain of F. tularensis has a reduced ability to both induce encystment in A. castellanii and invade human macrophages. We determined the crystal structure of REP34 to 2.05-Å resolution and demonstrate robust carboxypeptidase B-like activity for the enzyme. REP34 is a zinc-containing monomeric protein with close structural homology to the metallocarboxypeptidase family of peptidases. REP34 possesses a novel topology and substrate binding pocket that deviates from the canonical funnelin structure of carboxypeptidases, putatively resulting in a catalytic role for a conserved tyrosine and distinct S1' recognition site. Taken together, these results identify REP34 as an active carboxypeptidase, implicate the enzyme as a potential key F. tularensis effector protein, and may help elucidate a mechanistic understanding of F. tularensis infection of phagocytic cells.
    MeSH term(s) Amino Acid Sequence ; Bacterial Proteins/chemistry ; Bacterial Proteins/physiology ; Carboxypeptidases/chemistry ; Carboxypeptidases/physiology ; Catalytic Domain ; Cell Line ; Francisella tularensis/physiology ; Host-Pathogen Interactions ; Humans ; Models, Molecular ; Molecular Sequence Data ; Monocytes/microbiology ; Protein Structure, Secondary ; Structural Homology, Protein ; X-Ray Diffraction
    Chemical Substances Bacterial Proteins ; Carboxypeptidases (EC 3.4.-)
    Language English
    Publishing date 2014-09-17
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, U.S. Gov't, Non-P.H.S.
    ZDB-ID 2997-x
    ISSN 1083-351X ; 0021-9258
    ISSN (online) 1083-351X
    ISSN 0021-9258
    DOI 10.1074/jbc.M114.599381
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

To top