scholarly journals Structural characterization of a novel subfamily of leucine-rich repeat proteins from the human pathogenLeptospira interrogans

2015 ◽  
Vol 71 (6) ◽  
pp. 1351-1359 ◽  
Author(s):  
Isabelle Miras ◽  
Frederick Saul ◽  
Mireille Nowakowski ◽  
Patrick Weber ◽  
Ahmed Haouz ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Cell Attachment ◽  
Leucine Rich Repeat ◽  
Host Proteins ◽  
Repeat Proteins ◽  
Number Of Genes ◽  
Genes Encoding ◽  
Host Cell Attachment ◽  
Insight Into

PathogenicLeptospiraspp. are the agents of leptospirosis, an emerging zoonotic disease. Analyses ofLeptospiragenomes have shown that the pathogenic leptospires (but not the saprophytes) possess a large number of genes encoding proteins containing leucine-rich repeat (LRR) domains. In other pathogenic bacteria, proteins with LRR domains have been shown to be involved in mediating host-cell attachment and invasion, but their functions remain unknown inLeptospira. To gain insight into the potential function of leptospiral LRR proteins, the crystal structures of four LRR proteins that represent a novel subfamily with consecutive stretches of a 23-amino-acid LRR repeat motif have been solved. The four proteins analyzed adopt the characteristic α/β-solenoid horseshoe fold. The exposed residues of the inner concave surfaces of the solenoid, which constitute a putative functional binding site, are not conserved. The various leptospiral LRR proteins could therefore recognize distinct structural motifs of different host proteins and thus serve separate and complementary functions in the physiology of these bacteria.

scholarly journals The Tomato Cf-2 Disease Resistance Locus Comprises Two Functional Genes Encoding Leucine-Rich Repeat Proteins

Cell ◽  
1996 ◽  
Vol 84 (3) ◽  
pp. 451-459 ◽  
Author(s):  
Mark S Dixon ◽  
David A Jones ◽  
James S Keddie ◽  
Colwyn M Thomas ◽  
Kate Harrison ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Functional Genes ◽  
Resistance Locus ◽  
Leucine Rich Repeat ◽  
Repeat Proteins ◽  
Genes Encoding

scholarly journals Genome-Guided Characterization of Ochrobactrum sp. POC9 Enhancing Sewage Sludge Utilization—Biotechnological Potential and Biosafety Considerations

2018 ◽  
Vol 15 (7) ◽  
pp. 1501 ◽  
Author(s):  
Krzysztof Poszytek ◽  
Joanna Karczewska-Golec ◽  
Anna Ciok ◽  
Przemyslaw Decewicz ◽  
Mikolaj Dziurzynski ◽  
...  
Keyword(s):  
Sewage Sludge ◽  
Pathogenic Bacteria ◽  
Biogas Production ◽  
Treatment Plant ◽  
Antibiotic Resistance Genes ◽  
Biotechnological Potential ◽  
Sewage Sludge Sample ◽  
Complex Organic ◽  
Insight Into

Sewage sludge is an abundant source of microorganisms that are metabolically active against numerous contaminants, and thus possibly useful in environmental biotechnologies. However, amongst the sewage sludge isolates, pathogenic bacteria can potentially be found, and such isolates should therefore be carefully tested before their application. A novel bacterial strain, Ochrobactrum sp. POC9, was isolated from a sewage sludge sample collected from a wastewater treatment plant. The strain exhibited lipolytic, proteolytic, cellulolytic, and amylolytic activities, which supports its application in biodegradation of complex organic compounds. We demonstrated that bioaugmentation with this strain substantially improved the overall biogas production and methane content during anaerobic digestion of sewage sludge. The POC9 genome content analysis provided a deeper insight into the biotechnological potential of this bacterium and revealed that it is a metalotolerant and a biofilm-producing strain capable of utilizing various toxic compounds. The strain is resistant to rifampicin, chloramphenicol and β-lactams. The corresponding antibiotic resistance genes (including blaOCH and cmlA/floR) were identified in the POC9 genome. Nevertheless, as only few genes in the POC9 genome might be linked to pathogenicity, and none of those genes is a critical virulence factor found in severe pathogens, the strain appears safe for application in environmental biotechnologies.

scholarly journals Characterization of the Erwinia chrysanthemi gan Locus, Involved in Galactan Catabolism

2007 ◽  
Vol 189 (19) ◽  
pp. 7053-7061 ◽  
Author(s):  
Aurélie Delangle ◽  
Anne-France Prouvost ◽  
Virginie Cogez ◽  
Jean-Pierre Bohin ◽  
Jean-Marie Lacroix ◽  
...  
Keyword(s):  
Abc Transporter ◽  
Transport System ◽  
Pathogenic Bacteria ◽  
Erwinia Chrysanthemi ◽  
Potato Tubers ◽  
Inner Membrane ◽  
Saintpaulia Ionantha ◽  
Genes Encoding

ABSTRACT β-1,4-Galactan is a major component of the ramified regions of pectin. Analysis of the genome of the plant pathogenic bacteria Erwinia chrysanthemi revealed the presence of a cluster of eight genes encoding proteins potentially involved in galactan utilization. The predicted transport system would comprise a specific porin GanL and an ABC transporter made of four proteins, GanFGK2. Degradation of galactans would be catalyzed by the periplasmic 1,4-β-endogalactanase GanA, which released oligogalactans from trimer to hexamer. After their transport through the inner membrane, oligogalactans would be degraded into galactose by the cytoplasmic 1,4-β-exogalactanase GanB. Mutants affected for the porin or endogalactanase were unable to grow on galactans, but they grew on galactose and on a mixture of galactotriose, galactotetraose, galactopentaose, and galactohexaose. Mutants affected for the periplasmic galactan binding protein, the transporter ATPase, or the exogalactanase were only able to grow on galactose. Thus, the phenotypes of these mutants confirmed the functionality of the gan locus in transport and catabolism of galactans. These mutations did not affect the virulence of E. chrysanthemi on chicory leaves, potato tubers, or Saintpaulia ionantha, suggesting an accessory role of galactan utilization in the bacterial pathogeny.

scholarly journals Huge and variable diversity of episymbiotic CPR bacteria and DPANN archaea in groundwater ecosystems

2020 ◽  
Author(s):  
Christine He ◽  
Ray Keren ◽  
Michael Whittaker ◽  
Ibrahim F. Farag ◽  
Jennifer Doudna ◽  
...  
Keyword(s):  
Cell Attachment ◽  
Taxonomic Diversity ◽  
Host Cells ◽  
Groundwater Aquifers ◽  
Groundwater Ecosystems ◽  
Genomic Analyses ◽  
Host Cell Attachment ◽  
Health Relevance ◽  
Candidate Phyla Radiation

AbstractCandidate Phyla Radiation (CPR) bacteria and DPANN archaea are uncultivated, small-celled symbionts often detected in groundwater. However, variations in CPR/DPANN organism abundance, distribution, taxonomic diversity, and degree/nature of host association with groundwater chemistry remain understudied. Here, we performed genome-resolved metagenomic characterization of one agriculturally-impacted and seven pristine groundwater microbial communities in California, recovering 746 dereplicated CPR and DPANN genomes. Our finding of up to 31% CPR bacteria and 4% DPANN archaea in the pristine sites, which serve as local sources of drinking water, may hold health relevance, given growing awareness of the presence of CPR/DPANN organisms in human microbiomes and their association with disease. There is little species-level genome overlap across groundwater sites, indicating that CPR and DPANN communities are highly differentiated according to host populations and physicochemical conditions. Cryo-TEM imaging and genomic analyses indicate that CPR growth may be stimulated by attachment to the surface of host cells, and identified CPR and DPANN lineages with particularly prevalent and/or resilient host cell attachment. These results establish the huge but site-specific diversity of CPR bacteria and DPANN archaea coexisting with diverse hosts in groundwater aquifers, and raise important questions about potential impacts on human health.

scholarly journals Structural characterization of a nonhydrolyzing UDP-GlcNAc 2-epimerase from Neisseria meningitidis serogroup A

2020 ◽  
Vol 76 (11) ◽  
pp. 557-567
Author(s):  
Nicholas K. Hurlburt ◽  
Jasper Guan ◽  
Hoonsan Ong ◽  
Hai Yu ◽  
Xi Chen ◽  
...  
Keyword(s):  
Neisseria Meningitidis ◽  
Active Site ◽  
Pathogenic Bacteria ◽  
Allosteric Site ◽  
Additional Insight ◽  
Large Conformational Change ◽  
Surface Polysaccharides ◽  
Important Intermediate ◽  
Insight Into

Bacterial nonhydrolyzing UDP-N-acetylglucosamine 2-epimerases catalyze the reversible interconversion of UDP-N-acetylglucosamine (UDP-GlcNAc) and UDP-N-acetylmannosamine (UDP-ManNAc). UDP-ManNAc is an important intermediate in the biosynthesis of certain cell-surface polysaccharides, including those in some pathogenic bacteria, such as Neisseria meningitidis and Streptococcus pneumoniae. Many of these epimerases are allosterically regulated by UDP-GlcNAc, which binds adjacent to the active site and is required to initiate UDP-ManNAc epimerization. Here, two crystal structures of UDP-N-acetylglucosamine 2-epimerase from Neisseria meningitidis serogroup A (NmSacA) are presented. One crystal structure is of the substrate-free enzyme, while the other structure contains UDP-GlcNAc substrate bound to the active site. Both structures form dimers as seen in similar epimerases, and substrate binding to the active site induces a large conformational change in which two Rossmann-like domains clamp down on the substrate. Unlike other epimerases, NmSacA does not require UDP-GlcNAc to instigate the epimerization of UDP-ManNAc, although UDP-GlcNAc was found to enhance the rate of epimerization. In spite of the conservation of residues involved in binding the allosteric UDP-GlcNAc observed in similar UDP-GlcNAc 2-epimerases, the structures presented here do not contain UDP-GlcNAc bound in the allosteric site. These structural results provide additional insight into the mechanism and regulation of this critical enzyme and improve the structural understanding of the ability of NmSacA to epimerize modified substrates.

Characterization of two genes encoding leucine-rich repeat-containing proteins in grass carp Ctenopharyngodon idellus

2004 ◽  
Vol 56 (10) ◽  
pp. 710-721 ◽  
Author(s):  
M. X. Chang ◽  
P. Nie ◽  
H. X. Xie ◽  
B. J. Sun ◽  
Q. Gao
Keyword(s):  
Grass Carp ◽  
Ctenopharyngodon Idellus ◽  
Leucine Rich Repeat ◽  
Genes Encoding

scholarly journals O-fucosylation of thrombospondin-like repeats is required for processing of MIC2 and for efficient host cell invasion by Toxoplasma gondii tachyzoites

2018 ◽  
Author(s):  
Giulia Bandini ◽  
Deborah R. Leon ◽  
Carolin M. Hoppe ◽  
Yue Zhang ◽  
Carolina Agop-Nersesian ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Host Cell ◽  
Secretory Pathway ◽  
Cell Attachment ◽  
Host Cells ◽  
Type I ◽  
Human Foreskin Fibroblasts ◽  
Genes Encoding ◽  
Host Cell Attachment ◽  
Glycosylation Pathway

AbstractToxoplasma gondii is an intracellular parasite that causes disseminated infections which can lead to neurological damage in fetuses and immunocompromised individuals. Microneme protein 2 (MIC2)2, a member of the thrombospondin-related anonymous protein (TRAP) family, is a secreted protein important for motility, host cell attachment, invasion, and egress. MIC2 contains six thrombospondin type I repeats (TSRs) that are modified by C-mannose and O-fucose in Plasmodium spp. and mammals.Here we used mass spectrometry to show that the four TSRs in T. gondii MIC2 with protein O-fucosyltransferase 2 (POFUT2) acceptor sites are modified by a dHexHex disaccharide, while Trp residues within three TSRs are also modified with C-mannose. Disruption of genes encoding either pofut2 or nucleotide sugar transporter 2 (nst2), the putative GDP-fucose transporter, results in loss of MIC2 O-fucosylation, as detected by an antibody against the GlcFuc disaccharide, and markedly reduced cellular levels of MIC2. Furthermore, in 10-15% of the Δpofut2 or Δnst2 vacuoles, MIC2 accumulates earlier in the secretory pathway rather than localizing to micronemes. Dissemination of tachyzoites in human foreskin fibroblasts is reduced in these knockouts, which both show defects in attachment to and invasion of host cells comparable to the phenotype observed in the Βmic2.These results, which show O-fucosylation of TSRs is required for efficient processing of MIC2 and for normal parasite invasion, are consistent with the recent demonstration that P. falciparum Δpofut2 has decreased virulence and support a conserved role for this glycosylation pathway in quality control of TSR-containing proteins in eukaryotes.

scholarly journals Activation of TIR signaling is required for pattern-triggered immunity

2020 ◽  
Author(s):  
Hainan Tian ◽  
Siyu Chen ◽  
Zhongshou Wu ◽  
Kevin Ao ◽  
Hoda Yaghmaiean ◽  
...  
Keyword(s):  
Immune Responses ◽  
Interleukin 1 ◽  
Defense Responses ◽  
Effector Proteins ◽  
Leucine Rich Repeat ◽  
Number Of Genes ◽  
Genes Encoding ◽  
Signaling Activation ◽  
Tir Domains ◽  
The Relationship

AbstractPlant immune responses are mainly activated by two types of receptors. Plasma membrane-localized pattern recognition receptors (PRRs) recognize conserved features of microbes, and intracellular nucleotide-binding leucine rich repeat receptors (NLRs) recognize effector proteins from pathogens. NLRs possessing N-terminal Toll/interleukin-1 receptor (TIR) domains (TNLs) activate two parallel signaling pathways via the EDS1/PAD4/ADR1s and the EDS1/SAG101/NRG1s modules. The relationship between PRR-mediated pattern-triggered immunity (PTI) and TIR signaling is unclear. Here we report that activation of TIR signaling plays a key role in PTI. Blocking TIR signaling by knocking out components of the EDS1/PAD4/ADR1s and EDS1/SAG101/NRG1s modules results in attenuated PTI responses such as reduced salicylic acid (SA) levels and expression of defense genes, and compromised resistance against pathogens. Consistently, PTI is attenuated in transgenic plants that have reduced accumulation of NLRs. Upon treatment with PTI elicitors such as flg22 and nlp20, a large number of genes encoding TNLs or TIR domain-containing proteins are rapidly induced, likely responsible for activating TIR signaling during PTI. In support, overexpression of some of these genes results in activation of defense responses. Overall, our study reveals that TIR signaling activation is an important mechanism for boosting plant defense during PTI.

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