Crystallization and preliminary X-ray studies of SdiA from<i>Escherichia coli</i>

Wu, Chunai; Lokanath, N.K.; Kim, Dong Young; Nguyen, Lan-Anh T.; Kim, Kyeong Kyu

doi:10.1107/s1744309107059696

Cited by 4 publications

(3 citation statements)

References 11 publications

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“…Some reports have shown the expression of recombinant SdiA from culture medium supplemented with AHLs autoinducers ( Yao et al, 2006 ; Abed et al, 2014 ). Since we aimed to conduct EMSA with the K. pneumoniae SdiA protein in its apo form (i.e., not complexed with autoinducers), we did not add AHLs in the culture medium, as has been done by others ( Kanamaru et al, 2000 ; Yamamoto et al, 2001 ; Wu et al, 2008 ; Kim et al, 2013 ; Shimada et al, 2014 ; Nguyen et al, 2015 ; Lu et al, 2017 ). In brief, transformed BL21(DE3) was grown in 500 mL of LB medium at 37°C to an O.D.…”

Section: Methodsmentioning

confidence: 99%

SdiA, a Quorum-Sensing Regulator, Suppresses Fimbriae Expression, Biofilm Formation, and Quorum-Sensing Signaling Molecules Production in Klebsiella pneumoniae

et al. 2021

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Klebsiella pneumoniae is a Gram-negative pathogen that has become a worldwide concern due to the emergence of multidrug-resistant isolates responsible for various invasive infectious diseases. Biofilm formation constitutes a major virulence factor for K. pneumoniae and relies on the expression of fimbrial adhesins and aggregation of bacterial cells on biotic or abiotic surfaces in a coordinated manner. During biofilm aggregation, bacterial cells communicate with each other through inter- or intra-species interactions mediated by signallng molecules, called autoinducers, in a mechanism known as quorum sensing (QS). In most Gram-negative bacteria, intra-species communication typically involves the LuxI/LuxR system: LuxI synthase produces N-acyl homoserine lactones (AHLs) as autoinducers and the LuxR transcription factor is their cognate receptor. However, K. pneumoniae does not produce AHL but encodes SdiA, an orphan LuxR-type receptor that responds to exogenous AHL molecules produced by other bacterial species. While SdiA regulates several cellular processes and the expression of virulence factors in many pathogens, the role of this regulator in K. pneumoniae remains unknown. In this study, we describe the characterization of sdiA mutant strain of K. pneumoniae. The sdiA mutant strain has increased biofilm formation, which correlates with the increased expression of type 1 fimbriae, thus revealing a repressive role of SdiA in fimbriae expression and bacterial cell adherence and aggregation. On the other hand, SdiA acts as a transcriptional activator of cell division machinery assembly in the septum, since cells lacking SdiA regulator exhibited a filamentary shape rather than the typical rod shape. We also show that K. pneumoniae cells lacking SdiA regulator present constant production of QS autoinducers at maximum levels, suggesting a putative role for SdiA in the regulation of AI-2 production. Taken together, our results demonstrate that SdiA regulates cell division and the expression of virulence factors such as fimbriae expression, biofilm formation, and production of QS autoinducers in K. pneumoniae.

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Section: Methodsmentioning

confidence: 99%

SdiA, a Quorum-Sensing Regulator, Suppresses Fimbriae Expression, Biofilm Formation, and Quorum-Sensing Signaling Molecules Production in Klebsiella pneumoniae

et al. 2021

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“…We sought to define the mechanisms by which a P. aeruginosa LuxR-type receptor can respond to either AHL agonists or antagonists. As LasR was not suitable for study because of its low solubility in vitro (Lerat and Moran, 2004;Wu et al, 2008;Kim et al, 2014), we chose QscR because full-length QscR is amenable to structural studies, and like LasR, it recognizes 3OC12-HSL (Lintz et al, 2011). Reporter-based assays were used to define a small set of synthetic AHL agonists and antagonists developed in our laboratories (Mattmann et al, 2011) and elsewhere for investigation.…”

Section: Introductionmentioning

confidence: 99%

Mechanism of agonism and antagonism of the Pseudomonas aeruginosa quorum sensing regulator QscR with non‐native ligands

Wysoczynski-Horita

Boursier

Hill

et al. 2018

Molecular Microbiology

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Pseudomonas aeruginosa is an opportunistic pathogen that uses the process of quorum sensing (QS) to coordinate the expression of many virulence genes. During quorum sensing, N-acyl-homoserine lactone (AHL) signaling molecules regulate the activity of three LuxR-type transcription factors, LasR, RhlR and QscR. To better understand P. aeruginosa QS signal reception, we examined the mechanism underlying the response of QscR to synthetic agonists and antagonists using biophysical and structural approaches. The structure of QscR bound to a synthetic agonist reveals a novel mode of ligand binding supporting a general mechanism for agonist activity. In turn, antagonists of QscR with partial agonist activity were found to destabilize and greatly impair QscR dimerization and DNA binding. These results highlight the diversity of LuxR-type receptor responses to small molecule agonists and antagonists and demonstrate the potential for chemical strategies for the selective targeting of individual QS systems.

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“…Its crystal structure was solved using crystals that had a hexagonal space (Wu et al . ), and its direct interaction with HSL was proposed from modeling studies (Yao et al . ).…”

Section: Introductionmentioning

confidence: 99%

Roles of cell division control factor SdiA: recognition of quorum sensing signals and modulation of transcription regulation targets

Shimada

Matsui

et al. 2014

Genes to Cells

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In Gram‐negative bacteria, N‐acylhomoserine lactone (HSL) is used as a signal in cell–cell communication and quorum sensing (QS). The model prokaryote Escherichia coli lacks the system of HSL synthesis, but is capable of monitoring HSL signals in environment. Transcription factor SdiA for cell division control is believed to play a role as a HSL sensor. Using a collection of 477 species of chemically synthesized HSL analogues, we identified three synthetic signal molecules (SSMs) that bind in vitro to purified SdiA. After SELEX‐chip screening of SdiA‐binding DNA sequences, a striking difference was found between these SSMs in the pattern of regulation target genes on the E. coli genome. Based on Northern blot analysis in vivo, a set of target genes were found to be repressed by SdiA in the absence of effectors and derepressed by the addition of SSMs. Another set of genes were, however, expressed in the absence of effector ligands but repressed by the addition of SSMs. Taken together, we propose that the spectrum of taget gene selection by SdiA is modulated in multiple modes depending on the interacting HSL‐like signal molecules.

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Crystallization and preliminary X-ray studies of SdiA fromEscherichia coli

Cited by 4 publications

References 11 publications

SdiA, a Quorum-Sensing Regulator, Suppresses Fimbriae Expression, Biofilm Formation, and Quorum-Sensing Signaling Molecules Production in Klebsiella pneumoniae

SdiA, a Quorum-Sensing Regulator, Suppresses Fimbriae Expression, Biofilm Formation, and Quorum-Sensing Signaling Molecules Production in Klebsiella pneumoniae

Mechanism of agonism and antagonism of the Pseudomonas aeruginosa quorum sensing regulator QscR with non‐native ligands

Roles of cell division control factor SdiA: recognition of quorum sensing signals and modulation of transcription regulation targets

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