The Role of Secretion Systems and Small Molecules in Soft-RotEnterobacteriaceaePathogenicity

ABSTRACT The release of dipicolinic acid (DPA) during the germination of Bacillus subtilis spores by the cationic surfactant dodecylamine exhibited a pH optimum of ∼9 and a temperature optimum of 60°C. DPA release during dodecylamine germination of B. subtilis spores with fourfold-elevated levels of the SpoVA proteins that have been suggested to be involved in the release of DPA during nutrient germination was about fourfold faster than DPA release during dodecylamine germination of wild-type spores and was inhibited by HgCl2. Spores carrying temperature-sensitive mutants in the spoVA operon were also temperature sensitive in DPA release during dodecylamine germination as well as in lysozyme germination of decoated spores. In addition to DPA, dodecylamine triggered the release of amounts of Ca2+ almost equivalent to those of DPA, and at least one other abundant spore small molecule, glutamic acid, was released in parallel with Ca2+ and DPA. These data indicate that (i) dodecylamine triggers spore germination by opening a channel in the inner membrane for Ca2+-DPA and other small molecules, (ii) this channel is composed at least in part of proteins, and (iii) SpoVA proteins are involved in the release of Ca2+-DPA and other small molecules during spore germination, perhaps by being a part of a channel in the spore's inner membrane.

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Peptidomimetic Small Molecules Disrupt Type IV Secretion System Activity in Diverse Bacterial Pathogens

mBio ◽

10.1128/mbio.00221-16 ◽

2016 ◽

Vol 7 (2) ◽

Cited By ~ 22

Author(s):

Carrie L. Shaffer ◽

James A. D. Good ◽

Santosh Kumar ◽

K. Syam Krishnan ◽

Jennifer A. Gaddy ◽

...

Keyword(s):

Antibiotic Resistance ◽

Small Molecules ◽

Bacterial Pathogens ◽

Effector Proteins ◽

Type Iv Secretion ◽

Target Cells ◽

Effector Protein ◽

Secretion Systems ◽

Type Iv ◽

H Pylori

ABSTRACT Bacteria utilize complex type IV secretion systems (T4SSs) to translocate diverse effector proteins or DNA into target cells. Despite the importance of T4SSs in bacterial pathogenesis, the mechanism by which these translocation machineries deliver cargo across the bacterial envelope remains poorly understood, and very few studies have investigated the use of synthetic molecules to disrupt T4SS-mediated transport. Here, we describe two synthetic small molecules (C10 and KSK85) that disrupt T4SS-dependent processes in multiple bacterial pathogens. Helicobacter pylori exploits a pilus appendage associated with the cag T4SS to inject an oncogenic effector protein (CagA) and peptidoglycan into gastric epithelial cells. In H. pylori , KSK85 impedes biogenesis of the pilus appendage associated with the cag T4SS, while C10 disrupts cag T4SS activity without perturbing pilus assembly. In addition to the effects in H. pylori , we demonstrate that these compounds disrupt interbacterial DNA transfer by conjugative T4SSs in Escherichia coli and impede vir T4SS-mediated DNA delivery by Agrobacterium tumefaciens in a plant model of infection. Of note, C10 effectively disarmed dissemination of a derepressed IncF plasmid into a recipient bacterial population, thus demonstrating the potential of these compounds in mitigating the spread of antibiotic resistance determinants driven by conjugation. To our knowledge, this study is the first report of synthetic small molecules that impair delivery of both effector protein and DNA cargos by diverse T4SSs. IMPORTANCE Many human and plant pathogens utilize complex nanomachines called type IV secretion systems (T4SSs) to transport proteins and DNA to target cells. In addition to delivery of harmful effector proteins into target cells, T4SSs can disseminate genetic determinants that confer antibiotic resistance among bacterial populations. In this study, we sought to identify compounds that disrupt T4SS-mediated processes. Using the human gastric pathogen H. pylori as a model system, we identified and characterized two small molecules that prevent transfer of an oncogenic effector protein to host cells. We discovered that these small molecules also prevented the spread of antibiotic resistance plasmids in E. coli populations and diminished the transfer of tumor-inducing DNA from the plant pathogen A. tumefaciens to target cells. Thus, these compounds are versatile molecular tools that can be used to study and disarm these important bacterial machines.

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Interactions of small molecules with TiO2(110) surfaces: The role of defects

Journal of Vacuum Science & Technology A Vacuum Surfaces and Films ◽

10.1116/1.580291 ◽

1996 ◽

Vol 14 (3) ◽

pp. 1532-1538 ◽

Cited By ~ 14

Author(s):

Li‐Qiong Wang ◽

A. N. Shultz ◽

D. R. Baer ◽

M. H. Engelhard

Keyword(s):

Small Molecules

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The Role of Membranes in the Transport of Small Molecules

Organization of Prokaryotic Cell Membranes ◽

10.1201/9781351075237-1 ◽

2018 ◽

pp. 1-52 ◽

Cited By ~ 1

Author(s):

J. E. Leonard ◽

C. A. Lee ◽

A. J. Apperson ◽

S. S. Dills ◽

M. H. Saier

Keyword(s):

Small Molecules

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Minimal mechanistic component of proteasome activation and prevention of impairment by pathological oligomers

10.21203/rs.3.rs-900719/v1 ◽

2021 ◽

Author(s):

Janelle Chuah ◽

Tifffany Thibaudeau ◽

David Smith

Keyword(s):

Small Molecules ◽

Conformational Changes ◽

Bound State ◽

Proof Of Concept ◽

Α Subunit ◽

Gate Opening ◽

Allosteric Mechanism ◽

Dependent Mechanism ◽

Degradation Of Peptides

Abstract Impairment of proteasomal function has been implicated in neurodegenerative diseases, justifying the need to understand how the proteasome is activated for protein degradation. Here, using biochemical and structural (cryo-EM) strategies in both archaeal and mammalian proteasomes, we further determine the HbYX(-motif)-dependent mechanism of proteasomal activation used by multiple proteasome-activating complexes including the 19S Particle. We identify multiple proteasome α subunit residues involved in HbYX-dependent activation, a point mutation that activates the proteasome by partially mimicking a HbYX-bound state, and conformational changes involved in gate-opening with a 2.0A structure. Through an iterative process of peptide synthesis, we successfully design a HbYX-like dipeptide mimetic as a robust tool to elucidate how the motif autonomously activates the proteasome. The mimetic induces near complete gate-opening at saturating concentration, activating mammalian proteasomal degradation of peptides and proteins. Findings using our peptide mimetic suggest the HbYX-dependent mechanism requires cooperative binding in at least two intersubunit pockets of the α ring. Collectively, the results presented here unambiguously demonstrate the lone role of the HbYX tyrosine in the allosteric mechanism of proteasome activation and offer proof of concept for the robust potential of HbYX-like small molecules to activate the proteasome.

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Causal role of L-glutamine in sickle cell disease painful crises: a Mendelian randomization analysis

10.1101/872358 ◽

2019 ◽

Author(s):

Yann Iboudo ◽

Melanie E. Garrett ◽

Pablo Bartolucci ◽

Carlo Brugnara ◽

Clary B. Clish ◽

...

Keyword(s):

Sickle Cell Disease ◽

Small Molecules ◽

Causal Relationship ◽

Sickle Cell ◽

Drug Targets ◽

Mendelian Randomization ◽

Cell Disease ◽

Aseptic Necrosis ◽

Randomization Analysis

ABSTRACTIn a recent clinical trial, the metabolite L-glutamine was shown to reduce painful crises in sickle cell disease (SCD) patients. To confirm this observation and identify other metabolites implicated in SCD clinical heterogeneity, we profiled 129 metabolites in the plasma of 705 SCD patients. We tested correlations between metabolite levels and six SCD-related complications (painful crises, cholecystectomy, retinopathy, leg ulcer, priapism, aseptic necrosis) or estimated glomerular filtration rate (eGFR), and used Mendelian randomization (MR) to assess causality. We found a causal relationship between L-glutamine levels and painful crises (N=1,278, odds ratio (OR) [95% confidence interval] = 0.68 [0.52 – 0.89], P=0.0048). In two smaller SCD cohorts (N=299 and 406), the protective effect of L-glutamine was observed (OR=0.82 [0.50-1.34]), although the MR result was not significant (P=0.44). We identified 66 significant correlations between the levels of other metabolites and SCD-related complications or eGFR. We tested these correlations for causality using MR analyses and found no significant causal relationship. The baseline levels of quinolinic acid was associated with prospectively ascertained survival in SCD patients, and this effect was dependent on eGFR. Metabolomics provide a promising approach to prioritize small molecules that may serve as biomarkers or drug targets in SCD.

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PET Imaging Radiotracers of Chemokine Receptors

Molecules ◽

10.3390/molecules26175174 ◽

2021 ◽

Vol 26 (17) ◽

pp. 5174

Author(s):

Santosh R. Alluri ◽

Yusuke Higashi ◽

Kun-Eek Kil

Keyword(s):

Small Molecules ◽

Chemokine Receptors ◽

Brain Disorders ◽

Infectious Agents ◽

Cardiovascular Research ◽

Critical Signal ◽

Inflammatory Reactions ◽

Positron Emission

Chemokines and chemokine receptors have been recognized as critical signal components that maintain the physiological functions of various cells, particularly the immune cells. The signals of chemokines/chemokine receptors guide various leukocytes to respond to inflammatory reactions and infectious agents. Many chemokine receptors play supportive roles in the differentiation, proliferation, angiogenesis, and metastasis of diverse tumor cells. In addition, the signaling functions of a few chemokine receptors are associated with cardiac, pulmonary, and brain disorders. Over the years, numerous promising molecules ranging from small molecules to short peptides and antibodies have been developed to study the role of chemokine receptors in healthy states and diseased states. These drug-like candidates are in turn exploited as radiolabeled probes for the imaging of chemokine receptors using noninvasive in vivo imaging, such as positron emission tomography (PET). Recent advances in the development of radiotracers for various chemokine receptors, particularly of CXCR4, CCR2, and CCR5, shed new light on chemokine-related cancer and cardiovascular research and the subsequent drug development. Here, we present the recent progress in PET radiotracer development for imaging of various chemokine receptors.

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SPIKE PROTEIN AND ITS PROTEASES ROLE IN SARS-COV-2 PATHOGENICITY AND TREATMENT; A REVIEW

Proceedings of the Shevchenko Scientific Society. Medical Sciences ◽

10.25040/ntsh2021.01.05 ◽

2021 ◽

Vol 64 (1) ◽

Author(s):

Fateme Tavakoli Far ◽

◽

Ehsan Amiri-Ardekani ◽

Keyword(s):

Blood Pressure ◽

Severe Acute Respiratory Syndrome ◽

Small Molecules ◽

Cathepsin B ◽

Host Cells ◽

Spike Protein ◽

Pressure Regulation ◽

Common Receptor ◽

The World

Since December 2019, a novel beta coronavirus has spread around the world. This virus can cause severe acute respiratory syndrome (SARS). In this study, we reviewed proteases of SARS-CoV-2 based on related articles published in journals indexed by Scopus, PubMed, and Google Scholar from December 2019 to April 2020. Based on this study, we can claim that this coronavirus has about 76% genotype similarity to SARS coronavirus (SARS-CoV). Also, similarities between these two viruses have been found in the mechanism of entry into host cells and pathogenicity. ACE 2, the angiotensin convertase enzyme 2, plays a role in the Renin-Angiotensin-Aldosterone system (RAAS) and blood pressure regulation. Some mechanisms have been reported for the role of ACE 2 in the pathogenicity of SARS-CoV-2. For example, the interaction between the ACE 2 receptor and spike protein mediated by TMPRSS2, Cathepsin B/L, and other enzymes is responsible for the entry of the virus into human cells and pathogenicity. Some host cell endosomal enzymes are necessary to cleavage coronavirus spike protein and cause binding to their common receptor. So, we conclude that molecules like antibodies or small molecules like ACE 2 antagonists and soluble ACE 2 can be used as a good therapeutic candidate to prevent SARS-CoV-2.

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Mycobacterial Pan-Genome Analysis Suggests Important Role of Plasmids in the Radiation of Type VII Secretion Systems

Genome Biology and Evolution ◽

10.1093/gbe/evw001 ◽

2016 ◽

Vol 8 (2) ◽

pp. 387-402 ◽

Cited By ~ 37

Author(s):

Emilie Dumas ◽

Eva Christina Boritsch ◽

Mathias Vandenbogaert ◽

Ricardo C. Rodríguez de la Vega ◽

Jean-Michel Thiberge ◽

...

Keyword(s):

Genome Analysis ◽

Secretion Systems ◽

Pan Genome ◽

Type Vii Secretion

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Dissection of the Role of Pili and Type 2 and 3 Secretion Systems in Adherence and Biofilm Formation of an Atypical Enteropathogenic Escherichia coli Strain

Infection and Immunity ◽

10.1128/iai.00620-13 ◽

2013 ◽

Vol 81 (10) ◽

pp. 3793-3802 ◽

Cited By ~ 25

Author(s):

Rodrigo T. Hernandes ◽

Miguel A. De la Cruz ◽

Denise Yamamoto ◽

Jorge A. Girón ◽

Tânia A. T. Gomes

Keyword(s):

Escherichia Coli ◽

Biofilm Formation ◽

Coli Strain ◽

Mass Spectrometry Analysis ◽

Secretion Systems ◽

Content Type ◽

Spectrometry Analysis ◽

Rigid Rod

ABSTRACTAtypical enteropathogenicEscherichia coli(aEPEC) strains are diarrheal pathogens that lack bundle-forming pilus production but possess the virulence-associated locus of enterocyte effacement. aEPEC strain 1551-2 produces localized adherence (LA) on HeLa cells; however, its isogenic intimin (eae) mutant produces a diffuse-adherence (DA) pattern. In this study, we aimed to identify the DA-associated adhesin of the 1551-2eaemutant. Electron microscopy of 1551-2 identified rigid rod-like pili composed of an 18-kDa protein, which was identified as the major pilin subunit of type 1 pilus (T1P) by mass spectrometry analysis. Deletion offimAin 1551-2 affected biofilm formation but had no effect on adherence properties. Analysis of secreted proteins in supernatants of this strain identified a 150-kDa protein corresponding to SslE, a type 2 secreted protein that was recently reported to be involved in biofilm formation of rabbit and human EPEC strains. However, neither adherence nor biofilm formation was affected in a 1551-2sslEmutant. We then investigated the role of the EspA filament associated with the type 3 secretion system (T3SS) in DA by generating a doubleeae espAmutant. This strain was no longer adherent, strongly suggesting that the T3SS translocon is the DA adhesin. In agreement with these results, specific anti-EspA antibodies blocked adherence of the 1551-2eaemutant. Our data support a role for intimin in LA, for the T3SS translocon in DA, and for T1P in biofilm formation, all of which may act in concert to facilitate host intestinal colonization by aEPEC strains.

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