Faculty Opinions recommendation of The molecular structure and catalytic mechanism of a quorum-quenching N-acyl-L-homoserine lactone hydrolase.

2005 ◽  
Author(s):  
Wilhelm Boland
Keyword(s):  
Molecular Structure ◽  
Catalytic Mechanism ◽  
Quorum Quenching ◽  
Homoserine Lactone

scholarly journals The molecular structure and catalytic mechanism of a quorum-quenching N-acyl-L-homoserine lactone hydrolase

2005 ◽  
Vol 102 (49) ◽  
pp. 17606-17611 ◽  
Author(s):  
M. H. Kim ◽  
W.-C. Choi ◽  
H. O. Kang ◽  
J. S. Lee ◽  
B. S. Kang ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Catalytic Mechanism ◽  
Quorum Quenching ◽  
Homoserine Lactone

scholarly journals A single point mutation converts a glutaryl-7-aminocephalosporanic acid acylase into an N-acyl-homoserine lactone acylase

2021 ◽  
Author(s):  
Shereen A. Murugayah ◽  
Gary B. Evans ◽  
Joel D. A. Tyndall ◽  
Monica L. Gerth
Keyword(s):  
Single Point ◽  
Quorum Quenching ◽  
Homoserine Lactone ◽  
Site Directed Mutagenesis ◽  
Saturation Mutagenesis ◽  
Single Amino Acid ◽  
Single Point Mutation ◽  
Acyl Homoserine Lactone ◽  
Signalling Molecules ◽  
Single Amino Acid Residue

Abstract Objective To change the specificity of a glutaryl-7-aminocephalosporanic acid acylase (GCA) towards N-acyl homoserine lactones (AHLs; quorum sensing signalling molecules) by site-directed mutagenesis. Results Seven residues were identified by analysis of existing crystal structures as potential determinants of substrate specificity. Site-saturation mutagenesis libraries were created for each of the seven selected positions. High-throughput activity screening of each library identified two variants—Arg255Ala, Arg255Gly—with new activities towards N-acyl homoserine lactone substrates. Structural modelling of the Arg255Gly mutation suggests that the smaller side-chain of glycine (as compared to arginine in the wild-type enzyme) avoids a key clash with the acyl group of the N-acyl homoserine lactone substrate. Conclusions Mutation of a single amino acid residue successfully converted a GCA (with no detectable activity against AHLs) into an AHL acylase. This approach may be useful for further engineering of ‘quorum quenching’ enzymes.

scholarly journals AidH, an Alpha/Beta-Hydrolase Fold Family Member from an Ochrobactrum sp. Strain, Is a Novel N-Acylhomoserine Lactonase

2010 ◽  
Vol 76 (15) ◽  
pp. 4933-4942 ◽  
Author(s):  
Gui-Ying Mei ◽  
Xiao-Xue Yan ◽  
Ali Turak ◽  
Zhao-Qing Luo ◽  
Li-Qun Zhang
Keyword(s):  
Pathogenic Bacteria ◽  
Divalent Cations ◽  
Hydrolytic Enzyme ◽  
Quorum Quenching ◽  
Homoserine Lactone ◽  
Great Promise ◽  
Fold Family ◽  
Hydrolase Fold ◽  
Enzymatic Inactivation ◽  
Alpha Beta

ABSTRACT N-Acylhomoserine lactones (AHLs) are signaling molecules in many quorum-sensing (QS) systems that regulate interactions between various pathogenic bacteria and their hosts. Quorum quenching by the enzymatic inactivation of AHLs holds great promise in preventing and treating infections, and several such enzymes have been reported. In this study, we report the characterization of a novel AHL-degrading protein from the soil bacterium Ochrobactrum sp. strain T63. This protein, termed AidH, shares no similarity with any of the known AHL degradases but is highly homologous with a hydrolytic enzyme from Ochrobactrum anthropi ATCC 49188 that contains the alpha/beta-hydrolase fold. By liquid chromatography-mass spectrometry (MS) analysis, we demonstrate that AidH functions as an AHL-lactonase that hydrolyzes the ester bond of the homoserine lactone ring of AHLs. Mutational analyses indicate that the G-X-Nuc-X-G motif or the histidine residue conserved among alpha/beta-hydrolases is critical for the activity of AidH. Furthermore, the AHL-inactivating activity of AidH requires Mn2+ but not several other tested divalent cations. We also showed that AidH significantly reduces biofilm formation by Pseudomonas fluorescens 2P24 and the pathogenicity of Pectobacterium carotovorum, indicating that this enzyme is able to effectively quench QS-dependent functions in these bacteria by degrading AHLs.

scholarly journals Endophytic Actinomycetes: A Novel Source of Potential Acyl Homoserine Lactone Degrading Enzymes

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Surang Chankhamhaengdecha ◽  
Suphatra Hongvijit ◽  
Akkaraphol Srichaisupakit ◽  
Pattra Charnchai ◽  
Watanalai Panbangred
Keyword(s):  
Pathogenic Bacteria ◽  
Sequence Similarity ◽  
Soft Rot ◽  
Quorum Quenching ◽  
Homoserine Lactone ◽  
Amide Bond ◽  
Side Chain ◽  
Signal Molecules ◽  
Endophytic Actinomycetes

Several Gram-negative pathogenic bacteria employN-acyl-L-homoserine lactone (HSL) quorum sensing (QS) system to control their virulence traits. Degradation of acyl-HSL signal molecules by quorum quenching enzyme (QQE) results in a loss of pathogenicity in QS-dependent organisms. The QQE activity of actinomycetes in rhizospheric soil and inside plant tissue was explored in order to obtain novel strains with high HSL-degrading activity. Among 344 rhizospheric and 132 endophytic isolates, 127 (36.9%) and 68 (51.5%) of them, respectively, possessed the QQE activity. The highest HSL-degrading activity was at151.30±3.1 nmole/h/mL from an endophytic actinomycetes isolate, LPC029. The isolate was identified asStreptomycesbased on16S  rRNAgene sequence similarity. The QQE from LPC029 revealed HSL-acylase activity that was able to cleave an amide bond of acyl-side chain in HSL substrate as determined by HPLC. LPC029 HSL-acylase showed broad substrate specificity from C6- to C12-HSL in which C10HSL is the most favorable substrate for this enzyme. In anin vitropathogenicity assay, the partially purified HSL-acylase efficiently suppressed soft rot of potato caused byPectobacterium carotovorumssp.carotovorumas demonstrated. To our knowledge, this is the first report of HSL-acylase activity derived from an endophyticStreptomyces.

scholarly journals Quorum Quenching Properties and Probiotic Potentials of Intestinal Associated Bacteria in Asian Sea Bass Lates calcarifer

Marine Drugs ◽  
2019 ◽  
Vol 18 (1) ◽  
pp. 23 ◽  
Author(s):  
Reza Ghanei-Motlagh ◽  
Takavar Mohammadian ◽  
Darioush Gharibi ◽  
Simon Menanteau-Ledouble ◽  
Esmaeil Mahmoudi ◽  
...  
Keyword(s):  
High Capacity ◽  
Quorum Quenching ◽  
Homoserine Lactone ◽  
Amino Acid Sequences ◽  
Diffusion Method ◽  
Asian Sea Bass ◽  
Pathogenic Vibrio ◽  
Rdna Sequencing ◽  
Degrading Bacteria

Quorum quenching (QQ), the enzymatic degradation of N-acyl homoserine lactones (AHLs), has been suggested as a promising strategy to control bacterial diseases. In this study, 10 AHL-degrading bacteria isolated from the intestine of barramundi were identified by 16S rDNA sequencing. They were able to degrade both short and long-chain AHLs associated with several pathogenic Vibrio species (spp.) in fish, including N-[(RS)-3-Hydroxybutyryl]-l-homoserine lactone (3-oh-C4-HSL), N-Hexanoyl-l-homoserine lactone (C6-HSL), N-(β-Ketocaproyl)-l-homoserine lactone (3-oxo-C6-HSL), N-(3-Oxodecanoyl)-l-homoserine lactone (3-oxo-C10-HSL), N-(3-Oxotetradecanoyl)-l-homoserine lactone (3-oxo-C14-HSL). Five QQ isolates (QQIs) belonging to the Bacillus and Shewanella genera, showed high capacity to degrade both synthetic AHLs as well as natural AHLs produced by Vibrio harveyi and Vibrio alginolyticus using the well-diffusion method and thin-layer chromatography (TLC). The genes responsible for QQ activity, including aiiA, ytnP, and aaC were also detected. Analysis of the amino acid sequences from the predicted lactonases revealed the presence of the conserved motif HxHxDH. The selected isolates were further characterized in terms of their probiotic potentials in vitro. Based on our scoring system, Bacillus thuringiensis QQ1 and Bacillus cereus QQ2 exhibited suitable probiotic characteristics, including the production of spore and exoenzymes, resistance to bile salts and pH, high potential to adhere on mucus, appropriate growth abilities, safety to barramundi, and sensitivity to antibiotics. These isolates, therefore, constitute new QQ probiotics that could be used to control vibriosis in Lates calcalifer.

scholarly journals Diversity of Acyl Homoserine Lactone Molecules in Anaerobic Membrane Bioreactors Treating Sewage at Psychrophilic Temperatures

Membranes ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 320
Author(s):  
Shamas Tabraiz ◽  
Burhan Shamurad ◽  
Evangelos Petropoulos ◽  
Alex Charlton ◽  
Obaidullah Mohiudin ◽  
...  
Keyword(s):  
Membrane Bioreactor ◽  
Quorum Quenching ◽  
Homoserine Lactone ◽  
Membrane Bioreactors ◽  
Acyl Homoserine Lactone ◽  
Mixed Liquor ◽  
Anaerobic Membrane Bioreactor ◽  
Anaerobic Bioreactors ◽  
New Information ◽  
Anaerobic Membrane Bioreactors

This study explores the types of acyl homoserine lactone (AHL) and their concentrations in different compartments of different conventional anaerobic bioreactors: (i) an upflow anaerobic membrane bioreactor (UAnMBR, biofilm/mixed liquor (sludge)); (ii) an anaerobic membrane bioreactor (AnMBR, biofilm/mixed liquor (sludge)); and (iii) an upflow sludge blanket (UASB, sludge only), all operating at 15 °C. Ten types of the AHL, namely C4-HSL, 3-oxo-C4-HSL, C6-HSL, 3-oxo-C6-HSL, C8-HSL, 3-oxo-C8-HSL, C10-HSL, 3-oxo-C10-HSL, C12-HSL, and 3-oxo-C12-HSL, which were investigated in this study, were found in UAnMBR and UASB, whilst only six of them (C4-HSL, 3-oxo-C4-HSL, C8-HSL, C10-HSL, 3-oxo-C10-HSL, and C12-HSL) were found in AnMBR. Concentrations of total AHL were generally higher in the biofilm than the sludge for both membrane bioreactors trialed. C10-HSL was the predominant AHL found in all reactors (biofilm and sludge) followed by C4-HSL and C8-HSL. Overall, the UAnMBR biofilm and sludge had 10-fold higher concentrations of AHL compared to the AnMBR. C10-HSL was only correlated with bacteria (p < 0.05), whilst other types of AHL were correlated with both bacteria and archaea. This study improves our understanding of AHL-mediated Quorum Sensing (QS) in the biofilms/sludge of UAnMBR and AnMBR, and provides new information that could contribute to the development of quorum quenching anti-fouling strategies in such systems.

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