scholarly journals NMR structure of the C-terminal domain of TonB protein from Pseudomonas aeruginosa

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5412 ◽  
Author(s):  
Jesper S. Oeemig ◽  
O.H. Samuli Ollila ◽  
Hideo Iwaï
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Structural Changes ◽  
Nmr Structure ◽  
Dynamics Simulation ◽  
Solution Nmr ◽  
Gram Negative Bacteria ◽  
E Coli ◽  
Terminal Domain ◽  
Tonb Protein ◽  
Monomeric Structure

The TonB protein plays an essential role in the energy transduction system to drive active transport across the outer membrane (OM) using the proton-motive force of the cytoplasmic membrane of Gram-negative bacteria. The C-terminal domain (CTD) of TonB protein is known to interact with the conserved TonB box motif of TonB-dependent OM transporters, which likely induces structural changes in the OM transporters. Several distinct conformations of differently dissected CTDs of Escherichia coli TonB have been previously reported. Here we determined the solution NMR structure of a 96-residue fragment of Pseudomonas aeruginosa TonB (PaTonB-96). The structure shows a monomeric structure with the flexible C-terminal region (residues 338–342), different from the NMR structure of E. coli TonB (EcTonB-137). The extended and flexible C-terminal residues are confirmed by 15N relaxation analysis and molecular dynamics simulation. We created models for the PaTonB-96/TonB box interaction and propose that the internal fluctuations of PaTonB-96 makes it more accessible for the interactions with the TonB box and possibly plays a role in disrupting the plug domain of the TonB-dependent OM transporters.

scholarly journals Solution NMR Structure of the Ca2+-bound N-terminal Domain of CaBP7

2012 ◽  
Vol 287 (45) ◽  
pp. 38231-38243 ◽  
Author(s):  
Hannah V. McCue ◽  
Pryank Patel ◽  
Andrew P. Herbert ◽  
Lu-Yun Lian ◽  
Robert D. Burgoyne ◽  
...  
Keyword(s):  
Nmr Structure ◽  
Solution Nmr ◽  
Terminal Domain

scholarly journals Solution NMR structure of the N-terminal domain of the human DEK protein

2008 ◽  
Vol 17 (2) ◽  
pp. 205-215 ◽  
Author(s):  
Matthew Devany ◽  
Ferdinand Kappes ◽  
Kuan-Ming Chen ◽  
David M. Markovitz ◽  
Hiroshi Matsuo
Keyword(s):  
Nmr Structure ◽  
Solution Nmr ◽  
Terminal Domain

scholarly journals National Surveillance of Antimicrobial Susceptibility of Bacteremic Gram-Negative Bacteria with Emphasis on Community-Acquired Resistant Isolates: Report from the 2019 Surveillance of Multicenter Antimicrobial Resistance in Taiwan (SMART)

2020 ◽  
Vol 64 (10) ◽  
Author(s):  
Po-Yu Liu ◽  
Yu-Lin Lee ◽  
Min-Chi Lu ◽  
Pei-Lan Shao ◽  
Po-Liang Lu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Antimicrobial Resistance ◽  
Klebsiella Pneumoniae ◽  
Gram Negative Bacteria ◽  
National Surveillance ◽  
Gram Negative ◽  
Content Type ◽  
E Coli ◽  
Carbapenem Resistant

ABSTRACT A multicenter collection of bacteremic isolates of Escherichia coli (n = 423), Klebsiella pneumoniae (n = 372), Pseudomonas aeruginosa (n = 300), and Acinetobacter baumannii complex (n = 199) was analyzed for susceptibility. Xpert Carba-R assay and sequencing for mcr genes were performed for carbapenem- or colistin-resistant isolates. Nineteen (67.8%) carbapenem-resistant K. pneumoniae (n = 28) and one (20%) carbapenem-resistant E. coli (n = 5) isolate harbored blaKPC (n = 17), blaOXA-48 (n = 2), and blaVIM (n = 1) genes.

scholarly journals NMR structure of the N-terminal domain of E. coli DnaB helicase: implications for structure rearrangements in the helicase hexamer

Structure ◽  
1999 ◽  
Vol 7 (6) ◽  
pp. 681-690 ◽  
Author(s):  
Johan Weigelt ◽  
Susan E Brown ◽  
Caroline S Miles ◽  
Nicholas E Dixon ◽  
Gottfried Otting
Keyword(s):  
Nmr Structure ◽  
E Coli ◽  
Terminal Domain ◽  
Dnab Helicase

scholarly journals Regulatory Conservation and Divergence of ς32 Homologs from Gram-Negative Bacteria: Serratia marcescens, Proteus mirabilis, Pseudomonas aeruginosa, and Agrobacterium tumefaciens

1998 ◽  
Vol 180 (9) ◽  
pp. 2402-2408 ◽  
Author(s):  
Kenji Nakahigashi ◽  
Hideki Yanagi ◽  
Takashi Yura
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Heat Shock ◽  
Serratia Marcescens ◽  
Proteus Mirabilis ◽  
Heat Shock Response ◽  
Gram Negative Bacteria ◽  
Heat Shock Genes ◽  
Gram Negative ◽  
E Coli ◽  
Shock Response

ABSTRACT The heat shock response in Escherichia coli is mediated primarily by the rpoH gene, encoding ς32, which is specifically required for transcription of heat shock genes. A number of ς32 homologs have recently been cloned from gram-negative bacteria that belong to the gamma or alpha subdivisions of the proteobacteria. We report here some of the regulatory features of several such homologs (RpoH) expressed in E. coli as well as in respective cognate bacteria. When expressed in an E. coli ΔrpoH strain lacking its own ς32, these homologs activated the transcription of heat shock genes (groE and dnaK) from the start sites normally used in E. coli. The level of RpoH inSerratia marcescens and Pseudomonas aeruginosacells was very low at 30°C but was elevated markedly upon a shift to 42°C, as found previously with E. coli. The increased RpoH levels upon heat shock resulted from both increased synthesis and stabilization of the normally unstable RpoH protein. In contrast, the RpoH level in Proteus mirabilis was relatively high at 30°C and increased less markedly upon heat shock, mostly by increased synthesis; this ς32 homolog was already stable at 30°C, and little further stabilization occurred upon the shift to 42°C. The increased synthesis of RpoH homologs in all these gamma proteobacteria was observed even in the presence of rifampin, suggesting that the induction occurred at the level of translation. Thus, the basic regulatory strategy of the heat shock response by enhancing the RpoH level is well conserved in the gamma proteobacteria, but some divergence in the actual mechanisms used occurred during evolution.

scholarly journals Biotinylation Facilitates the Uptake of Large Peptides by Escherichia coli and Other Gram-Negative Bacteria

2005 ◽  
Vol 71 (4) ◽  
pp. 1850-1855 ◽  
Author(s):  
Jennifer R. Walker ◽  
Elliot Altman
Keyword(s):  
Escherichia Coli ◽  
Amino Acids ◽  
Pseudomonas Aeruginosa ◽  
Gram Negative Bacteria ◽  
Cell Fractionation ◽  
Peptide Antibiotics ◽  
Small Peptides ◽  
Gram Negative ◽  
E Coli ◽  
Serovar Typhimurium

ABSTRACT Gram-negative bacteria such as Escherichia coli can normally only take up small peptides less than 650 Da, or five to six amino acids, in size. We have found that biotinylated peptides up to 31 amino acids in length can be taken up by E. coli and that uptake is dependent on the biotin transporter. Uptake could be competitively inhibited by free biotin or avidin and blocked by the protonophore carbonyl m-chlorophenylhydrazone and was abolished in E. coli mutants that lacked the biotin transporter. Biotinylated peptides could be used to supplement the growth of a biotin auxotroph, and the transported peptides were shown to be localized to the cytoplasm in cell fractionation experiments. The uptake of biotinylated peptides was also demonstrated for two other gram-negative bacteria, Salmonella enterica serovar Typhimurium and Pseudomonas aeruginosa. This finding may make it possible to create new peptide antibiotics that can be used against gram-negative pathogens. Researchers have used various moieties to cause the illicit transport of compounds in bacteria, and this study demonstrates the illicit transport of the largest known compound to date.

scholarly journals Colonization and Resistance Dynamics of Gram-Negative Bacteria in Patients during and after Hospitalization

2005 ◽  
Vol 49 (7) ◽  
pp. 2879-2886 ◽  
Author(s):  
P. Margreet G. Filius ◽  
Inge C. Gyssens ◽  
Irma M. Kershof ◽  
Patty J. E. Roovers ◽  
Alewijn Ott ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Susceptibility Testing ◽  
General Ward ◽  
Gram Negative Bacteria ◽  
Icu Patients ◽  
Gram Negative ◽  
E Coli ◽  
General Wards ◽  
Colonization Rates

ABSTRACT The colonization and resistance dynamics of aerobic gram-negative bacteria in the intestinal and oropharyngeal microfloras of patients admitted to intensive care units (ICU) and general wards were investigated during and after hospitalization. A total of 3,316 specimens were obtained from patients upon admission, once weekly during hospitalization, at discharge from the ICU, at discharge from the hospital, and 1 and 3 months after discharge from the hospital. Five colonies per specimen were selected for identification and susceptibility testing. In both patient populations, the gram-negative colonization rates in oropharyngeal specimens increased during hospitalization and did not decrease in the 3 months after discharge. In rectal specimens, colonization rates decreased during hospitalization and increased after discharge. There was a change in species distribution among the dominant microfloras during hospitalization. Klebsiella spp., Enterobacter spp., Serratia marcescens, and Pseudomonas aeruginosa were isolated more often, whereas the frequency of Escherichia coli declined. The percentage of ICU patients colonized with ampicillin- and/or cephalothin-resistant fecal E. coli was significantly increased at discharge from the hospital and did not change in the 3 months after discharge. The emergence of multidrug resistance was observed for E. coli during patient stays in the ICU. Resistance frequencies in E. coli significantly increased with the length of stay in the ICU. For the general ward population, no significant changes in resistance frequencies were found during hospitalization. From a population perspective, the risk of dissemination of resistant gram-negative bacteria into the community through hospitalized patients appears to be low for general ward patients but is noticeably higher among ICU patients.

scholarly journals Bacteriological Profile and Antibiogram of Bacterial Isolates from Pus Samples in Tertiary Care Hospital of Kathmandu

2018 ◽  
Vol 4 ◽  
pp. 55-62
Author(s):  
Upendra Pandeya ◽  
Mithileshwor Raut ◽  
Saru Bhattarai ◽  
Padam Raj Bhatt ◽  
Puspa Raj Dahal
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Polymyxin B ◽  
Gram Negative Bacteria ◽  
Bacterial Isolates ◽  
Susceptibility Pattern ◽  
Gram Negative ◽  
Clinical Specimens ◽  
E Coli ◽  
Acinetobacter Spp ◽  
Effective Drugs

Objectives: The main aim of the study was to isolate and identify the bacterial agent and to determine the susceptibility pattern of isolates to different antibiotics.Methods: This retrospective study was conducted from February to October 2015 in microbiology laboratory of All Nepal Hospital Kathmandu, Nepal. The clinical specimens were processed for isolation and identification of bacteria following standard microbiological procedures. Antibiotic susceptibility pattern of isolates were determined according to CLSI guidelines (CLSI 2014)Results: A total of 271 clinical specimens were processed where 164 (60.5%) showed growth positivity. A total 164 bacterial isolates were detected among which 84 (51.22%) were Gram positive 80 (48.78%) were Gram negative bacteria. Thirteen different species of bacteria were isolated. The most prevalent isolate was Staphylococcus aureus 53 (32.30%) followed by E. coli 34 (20.80%), (CoNS) 15 (9.10%), Klebsiella pneumoniae 15 (9.10%), Enterococcus fecalis 12(7.30%), Pseudomonas aeruginosa 10 (6.10%), Acinetobacter spp. 7 (4.30%) Citrobacter spp., Proteus spp., Klebsiella oxytoca were less common. S. aureus was most susceptible to Amikacin. Vancomycin was the most effective drugs for Enterococcus fecalis. Among Gram negative bacteria E. coli was found most sensitive to Polymyxin B (100%) and Imipenem (76.5%) where Pseudomonas aeruginosa was sensitive to, Amikacin, Imipenem (80%). Polymyxin B was the most effective drugs for Klebsiella pneumoniae. Acinetobacter spp. was found highly resistant to different antibiotics.Conclusion: Antibiotic susceptibility evaluation showed Aminoglycosides, Phenicols Polymyxin, and Imipenem was the most effective drugs overall.

scholarly journals Correct Sorting of Lipoproteins into the Inner and Outer Membranes ofPseudomonas aeruginosaby theEscherichia coliLolCDE Transport System

mBio ◽  
2019 ◽  
Vol 10 (2) ◽  
Author(s):  
Christian Lorenz ◽  
Thomas J. Dougherty ◽  
Stephen Lory
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Outer Membrane ◽  
Transport Systems ◽  
Gram Negative Bacteria ◽  
Inner Membrane ◽  
Gram Negative ◽  
Content Type ◽  
E Coli ◽  
Outer Membranes

ABSTRACTBiogenesis of the outer membrane of Gram-negative bacteria depends on dedicated macromolecular transport systems. The LolABCDE proteins make up the machinery for lipoprotein trafficking from the inner membrane (IM) across the periplasm to the outer membrane (OM). The Lol apparatus is additionally responsible for differentiating OM lipoproteins from those for the IM. InEnterobacteriaceae, a default sorting mechanism has been proposed whereby an aspartic acid at position +2 of the mature lipoproteins prevents Lol recognition and leads to their IM retention. In other bacteria, the conservation of sequences immediately following the acylated cysteine is variable. Here we show that inPseudomonas aeruginosa, the three essential Lol proteins (LolCDE) can be replaced with those fromEscherichia coli. TheP. aeruginosalipoproteins MexA, OprM, PscJ, and FlgH, with different sequences at their N termini, were correctly sorted by either theE. coliorP. aeruginosaLolCDE. We further demonstrate that an inhibitor ofE. coliLolCDE is active againstP. aeruginosaonly when expressing theE. coliorthologues. Our work shows that Lol proteins recognize a wide range of signals, consisting of an acylated cysteine and a specific conformation of the adjacent domain, determining IM retention or transport to the OM.IMPORTANCEGram-negative bacteria build their outer membranes (OM) from components that are initially located in the inner membrane (IM). A fraction of lipoproteins is transferred to the OM by the transport machinery consisting of LolABCDE proteins. Our work demonstrates that the LolCDE complexes of the transport pathways ofEscherichia coliandPseudomonas aeruginosaare interchangeable, with theE. coliorthologues correctly sorting theP. aeruginosalipoproteins while retaining their sensitivity to a small-molecule inhibitor. These findings question the nature of IM retention signals, identified inE. colias aspartate at position +2 of mature lipoproteins. We propose an alternative model for the sorting of IM and OM lipoproteins based on their relative affinities for the IM and the ability of the promiscuous sorting machinery to deliver lipoproteins to their functional sites in the OM.

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