Search results for "Escherichia coli Proteins"
showing 10 items of 121 documents
Essentiality Is a Strong Determinant of Protein Rates of Evolution during Mutation Accumulation Experiments in Escherichia coli
2016
[EN] The Neutral Theory of Molecular Evolution is considered the most powerful theory to understand the evolutionary behavior of proteins. One of the main predictions of this theory is that essential proteins should evolve slower than dispensable ones owing to increased selective constraints. Comparison of genomes of different species, however, has revealed only small differences between the rates of evolution ofessential and nonessential proteins. In some analyses, these differences vanish once confounding factors are controlled for, whereas in other cases essentiality seems to have an independent, albeit small, effect. It has been argued that comparing relatively distant genomes may entai…
Cellular Concentrations of the Transporters DctA and DcuB and the Sensor DcuS of Escherichia coli and the Contributions of Free and Complexed DcuS to…
2017
ABSTRACT In Escherichia coli , the catabolism of C 4 -dicarboxylates is regulated by the DcuS-DcuR two-component system. The functional state of the sensor kinase DcuS is controlled by C 4 -dicarboxylates (like fumarate) and complexation with the C 4 -dicarboxylate transporters DctA and DcuB, respectively. Free DcuS (DcuS F ) is known to be constantly active even in the absence of fumarate, whereas the DcuB-DcuS and DctA-DcuS complexes require fumarate for activation. To elucidate the impact of the transporters on the functional state of DcuS and the concentrations of DcuS F and DcuB-DcuS (or DctA-DcuS), the absolute levels of DcuS, DcuB, and DctA were determined in aerobically or anaerobic…
C 4 -Dicarboxylate Utilization in Aerobic and Anaerobic Growth
2016
C 4 -dicarboxylates and the C 4 -dicarboxylic amino acid l -aspartate support aerobic and anaerobic growth of Escherichia coli and related bacteria. In aerobic growth, succinate, fumarate, D - and L -malate, L -aspartate, and L -tartrate are metabolized by the citric acid cycle and associated reactions. Because of the interruption of the citric acid cycle under anaerobic conditions, anaerobic metabolism of C 4 -dicarboxylates depends on fumarate reduction to succinate (fumarate respiration). In some related bacteria (e.g., Klebsiella ), utilization of C 4 -dicarboxylates, such as tartrate, is independent of fumarate respiration and uses a Na + -dependent membrane-bound oxaloacetate decarbo…
Transmembrane signaling and cytoplasmic signal conversion by dimeric transmembrane helix 2 and a linker domain of the DcuS sensor kinase
2020
Transmembrane (TM) signaling is a key process of membrane-bound sensor kinases. The C4-dicarboxylate (fumarate) responsive sensor kinase DcuS of Escherichia coli is anchored by TM helices TM1 and TM2 in the membrane. Signal transmission across the membrane relies on the piston-type movement of the periplasmic part of TM2. To define the role of TM2 in TM signaling, we use oxidative Cys cross-linking to demonstrate that TM2 extends over the full distance of the membrane and forms a stable TM homodimer in both the inactive and fumarate-activated state of DcuS. An S186xxxGxxxG194 motif is required for the stability and function of the TM2 homodimer. The TM2 helix further extends on the periplas…
Plasmonic Nanosensors for the Determination of Drug Effectiveness on Membrane Receptors.
2016
We demonstrate the potential of the NanoSPR (nanoscale surface plasmon resonance sensors) method as a simple and cheap tool for the quantitative study of membrane protein–protein interactions. We use NanoSPR to determine the effectiveness of two potential drug candidates that inhibit the protein complex formation between FtsA and ZipA at initial stages of bacterial division. As the NanoSPR method relies on individual gold nanorods as sensing elements, there is no need for fluorescent labels or organic cosolvents, and it provides intrinsically high statistics. NanoSPR could become a powerful tool in drug development, drug delivery, and membrane studies.
Single Particle Plasmon Sensors as Label-Free Technique To Monitor MinDE Protein Wave Propagation on Membranes.
2016
We use individual gold nanorods as pointlike detectors for the intrinsic dynamics of an oscillating biological system. We chose the pattern forming MinDE protein system from Escherichia coli (E. coli), a prominent example for self-organized chemical oscillations of membrane-associated proteins that are involved in the bacterial cell division process. Similar to surface plasmon resonance (SPR), the gold nanorods report changes in their protein surface coverage without the need for fluorescence labeling, a technique we refer to as NanoSPR. Comparing the dynamics for fluorescence labeled and unlabeled proteins, we find a reduction of the oscillation period by about 20%. The absence of photoble…
Detection of plasmid-mediated colistin resistance, mcr-1 gene, in Escherichia coli isolated from high-risk patients with acute leukemia in Spain
2019
Background: Bacterial infections in immunocompromised patients are associated with a high mortality and morbidity rate. In this high-risk group, the presence of multidrug-resistant (MDR) bacteria, particularly bacteria that harbor a transferable antibiotic resistance gene, complicates the management of bacterial infections. In this study, we investigated the presence of the transferable colistin resistance mcr genes in patients with leukemia in Spain. Methods: 217 fecal samples collected in 2013-2015 from 56 patients with acute leukemia and colonized with MDR Enterobacteriaceae strains, were screened on September 2017 for the presence of the colistin resistance mcr genes (mcr-1 to -5) by mu…
Revisiting the pH-gated conformational switch on the activities of HisKA-family histidine kinases
2020
13 páginas, 6 figuras, 3 tablas
Discovery and validation of 2-styryl substituted benzoxazin-4-ones as a novel scaffold for rhomboid protease inhibitors
2017
Abstract Rhomboids are intramembrane serine proteases with diverse physiological functions in organisms ranging from archaea to humans. Crystal structure analysis has provided a detailed understanding of the catalytic mechanism, and rhomboids have been implicated in various disease contexts. Unfortunately, the design of specific rhomboid inhibitors has lagged behind, and previously described small molecule inhibitors displayed insufficient potency and/or selectivity. Using a computer-aided approach, we focused on the discovery of novel scaffolds with reduced liabilities and the possibility for broad structural variations. Docking studies with the E. coli rhomboid GlpG indicated that 2-styry…
Insights into the inhibited form of the redox-sensitive SufE-like sulfur acceptor CsdE
2017
17 p.-8 fig.