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  1. Article ; Online: Vibrio cholerae biofilms use modular adhesins with glycan-targeting and nonspecific surface binding domains for colonization

    Xin Huang / Thomas Nero / Ranjuna Weerasekera / Katherine H. Matej / Alex Hinbest / Zhaowei Jiang / Rebecca F. Lee / Longjun Wu / Cecilia Chak / Japinder Nijjer / Isabella Gibaldi / Hang Yang / Nathan Gamble / Wai-Leung Ng / Stacy A. Malaker / Kaelyn Sumigray / Rich Olson / Jing Yan

    Nature Communications, Vol 14, Iss 1, Pp 1-

    2023  Volume 14

    Abstract: Abstract Bacterial biofilms are formed on environmental surfaces and host tissues, and facilitate host colonization and antibiotic resistance by human pathogens. Bacteria often express multiple adhesive proteins (adhesins), but it is often unclear ... ...

    Abstract Abstract Bacterial biofilms are formed on environmental surfaces and host tissues, and facilitate host colonization and antibiotic resistance by human pathogens. Bacteria often express multiple adhesive proteins (adhesins), but it is often unclear whether adhesins have specialized or redundant roles. Here, we show how the model biofilm-forming organism Vibrio cholerae uses two adhesins with overlapping but distinct functions to achieve robust adhesion to diverse surfaces. Both biofilm-specific adhesins Bap1 and RbmC function as a “double-sided tape”: they share a β-propeller domain that binds to the biofilm matrix exopolysaccharide, but have distinct environment-facing domains. Bap1 adheres to lipids and abiotic surfaces, while RbmC mainly mediates binding to host surfaces. Furthermore, both adhesins contribute to adhesion in an enteroid monolayer colonization model. We expect that similar modular domains may be utilized by other pathogens, and this line of research can potentially lead to new biofilm-removal strategies and biofilm-inspired adhesives.
    Keywords Science ; Q
    Language English
    Publishing date 2023-04-01T00:00:00Z
    Publisher Nature Portfolio
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Article ; Online: Structural basis of mammalian glycan targeting by Vibrio cholerae cytolysin and biofilm proteins.

    Swastik De / Katherine Kaus / Shada Sinclair / Brandon C Case / Rich Olson

    PLoS Pathogens, Vol 14, Iss 2, p e

    2018  Volume 1006841

    Abstract: Vibrio cholerae is an aquatic gram-negative microbe responsible for cholera, a pandemic disease causing life-threatening diarrheal outbreaks in populations with limited access to health care. Like most pathogenic bacteria, V. cholerae secretes virulence ... ...

    Abstract Vibrio cholerae is an aquatic gram-negative microbe responsible for cholera, a pandemic disease causing life-threatening diarrheal outbreaks in populations with limited access to health care. Like most pathogenic bacteria, V. cholerae secretes virulence factors to assist colonization of human hosts, several of which bind carbohydrate receptors found on cell-surfaces. Understanding how pathogenic virulence proteins specifically target host cells is important for the development of treatment strategies to fight bacterial infections. Vibrio cholerae cytolysin (VCC) is a secreted pore-forming toxin with a carboxy-terminal β-prism domain that targets complex N-glycans found on mammalian cell-surface proteins. To investigate glycan selectivity, we studied the VCC β-prism domain and two additional β-prism domains found within the V. cholerae biofilm matrix protein RbmC. We show that the two RbmC β-prism domains target a similar repertoire of complex N-glycan receptors as VCC and find through binding and modeling studies that a branched pentasaccharide core (GlcNAc2-Man3) represents the likely footprint interacting with these domains. To understand the structural basis of V. cholerae β-prism selectivity, we solved high-resolution crystal structures of fragments of the pentasaccharide core bound to one RbmC β-prism domain and conducted mutagenesis experiments on the VCC toxin. Our results highlight a common strategy for cell-targeting utilized by both toxin and biofilm matrix proteins in Vibrio cholerae and provide a structural framework for understanding the specificity for individual receptors. Our results suggest that a common strategy for disrupting carbohydrate interactions could affect multiple virulence factors produced by V. cholerae, as well as similar β-prism domains found in other vibrio pathogens.
    Keywords Immunologic diseases. Allergy ; RC581-607 ; Biology (General) ; QH301-705.5
    Subject code 572
    Language English
    Publishing date 2018-02-01T00:00:00Z
    Publisher Public Library of Science (PLoS)
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Article ; Online: NMR structure of the Bacillus cereus hemolysin II C-terminal domain reveals a novel fold

    Anne R. Kaplan / Katherine Kaus / Swastik De / Rich Olson / Andrei T. Alexandrescu

    Scientific Reports, Vol 7, Iss 1, Pp 1-

    2017  Volume 13

    Abstract: Abstract In addition to multiple virulence factors, Bacillus cereus a pathogen that causes food poisoning and life-threatening wound infections, secretes the pore-forming toxin hemolysin II (HlyII). The HlyII toxin has a unique 94 amino acid C-terminal ... ...

    Abstract Abstract In addition to multiple virulence factors, Bacillus cereus a pathogen that causes food poisoning and life-threatening wound infections, secretes the pore-forming toxin hemolysin II (HlyII). The HlyII toxin has a unique 94 amino acid C-terminal domain (HlyIIC). HlyIIC exhibits splitting of NMR resonances due to cis/trans isomerization of a single proline near the C-terminus. To overcome heterogeneity, we solved the structure of P405M-HlyIIC, a mutant that exclusively stabilizes the trans state. The NMR structure of HlyIIC reveals a novel fold, consisting of two subdomains αA-β1-β2 and β3-β4-αB-β5, that come together in a barrel-like structure. The barrel core is fastened by three layers of hydrophobic residues. The barrel end opposite the HlyIIC-core has a positively charged surface, that by binding negatively charged moieties on cellular membranes, may play a role in target-cell surface recognition or stabilization of the heptameric pore complex. In the WT domain, dynamic flexibility occurs at the N-terminus and the first α-helix that connects the HlyIIC domain to the HlyII-core structure. In the destabilizing P405M mutant, increased flexibility is evident throughout the first subdomain, suggesting that the HlyIIC structure may have arisen through gene fusion.
    Keywords Medicine ; R ; Science ; Q
    Subject code 572
    Language English
    Publishing date 2017-06-01T00:00:00Z
    Publisher Nature Portfolio
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Article: Glycan Specificity of the Vibrio vulnificus Hemolysin Lectin Outlines Evolutionary History of Membrane Targeting by a Toxin Family

    Kaus, Katherine / Jeffrey W. Lary / James L. Cole / Rich Olson

    Journal of Molecular Biology. 2014 July 29, v. 426

    2014  

    Abstract: Pore-forming toxins (PFTs) are a class of pathogen-secreted molecules that oligomerize to form transmembrane channels in cellular membranes. Determining the mechanism for how PFTs bind membranes is important in understanding their role in disease and for ...

    Abstract Pore-forming toxins (PFTs) are a class of pathogen-secreted molecules that oligomerize to form transmembrane channels in cellular membranes. Determining the mechanism for how PFTs bind membranes is important in understanding their role in disease and for developing possible ways to block their action. Vibrio vulnificus, an aquatic pathogen responsible for severe food poisoning and septicemia in humans, secretes a PFT called V. vulnificus hemolysin (VVH), which contains a single C-terminal targeting domain predicted to resemble a β-trefoil lectin fold. In order to understand the selectivity of the lectin for glycan motifs, we expressed the isolated VVH β-trefoil domain and used glycan-chip screening to identify that VVH displays a preference for terminal galactosyl groups including N-acetyl-d-galactosamine and N-acetyl-d-lactosamine. The X-ray crystal structure of the VVH lectin domain solved to 2.0Å resolution reveals a heptameric ring arrangement similar to the oligomeric form of the related, but inactive, lectin from Vibrio cholerae cytolysin. Structures bound to glycerol, N-acetyl-d-galactosamine, and N-acetyl-d-lactosamine outline a common and versatile mode of recognition allowing VVH to target a wide variety of cell-surface ligands. Sequence analysis in light of our structural and functional data suggests that VVH may represent an earlier step in the evolution of Vibrio PFTs.
    Keywords Vibrio cholerae ; Vibrio vulnificus ; X-ray diffraction ; cell membranes ; evolution ; foodborne illness ; glycerol ; hemolysins ; humans ; lectins ; ligands ; pathogens ; screening ; septicemia ; sequence analysis ; toxins
    Language English
    Dates of publication 2014-0729
    Size p. 2800-2812.
    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.2014.05.021
    Database NAL-Catalogue (AGRICOLA)

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  5. Article ; Online: Structure of a pheromone receptor-associated MHC molecule with an open and empty groove.

    Rich Olson / Kathryn E Huey-Tubman / Catherine Dulac / Pamela J Bjorkman

    PLoS Biology, Vol 3, Iss 8, p e

    2005  Volume 257

    Abstract: Neurons in the murine vomeronasal organ (VNO) express a family of class Ib major histocompatibility complex (MHC) proteins (M10s) that interact with the V2R class of VNO receptors. This interaction may play a direct role in the detection of pheromonal ... ...

    Abstract Neurons in the murine vomeronasal organ (VNO) express a family of class Ib major histocompatibility complex (MHC) proteins (M10s) that interact with the V2R class of VNO receptors. This interaction may play a direct role in the detection of pheromonal cues that initiate reproductive and territorial behaviors. The crystal structure of M10.5, an M10 family member, is similar to that of classical MHC molecules. However, the M10.5 counterpart of the MHC peptide-binding groove is open and unoccupied, revealing the first structure of an empty class I MHC molecule. Similar to empty MHC molecules, but unlike peptide-filled MHC proteins and non-peptide-binding MHC homologs, M10.5 is thermally unstable, suggesting that its groove is normally occupied. However, M10.5 does not bind endogenous peptides when expressed in mammalian cells or when offered a mixture of class I-binding peptides. The F pocket side of the M10.5 groove is open, suggesting that ligands larger than 8-10-mer class I-binding peptides could fit by extending out of the groove. Moreover, variable residues point up from the groove helices, rather than toward the groove as in classical MHC structures. These data suggest that M10s are unlikely to provide specific recognition of class I MHC-binding peptides, but are consistent with binding to other ligands, including proteins such as the V2Rs.
    Keywords Biology (General) ; QH301-705.5
    Subject code 570
    Language English
    Publishing date 2005-08-01T00:00:00Z
    Publisher Public Library of Science (PLoS)
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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