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Scott P Hefty - One of the best experts on this subject based on the ideXlab platform.
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chlamydia trachomatis Protein ct009 is a structural and functional homolog to the key morphogenesis component rodz and interacts with division septal plane localized MreB
Molecular Microbiology, 2015Co-Authors: Kyle Evan Kemege, John M Hickey, Michael L Barta, Jason R Wickstrum, Namita Ashwin Balwalli, Scott Lovell, Kevin P Battaile, Scott P HeftyAbstract:Cell division in Chlamydiae is poorly understood as apparent homologs to most conserved bacterial cell division Proteins are lacking and presence of elongation (rod shape) associated Proteins indicate non-canonical mechanisms may be employed. The rod-shape determining Protein MreB has been proposed as playing a unique role in chlamydial cell division. In other organisms, MreB is part of an elongation complex that requires RodZ for proper function. A recent study reported that the Protein encoded by ORF CT009 interacts with MreB despite low sequence similarity to RodZ. The studies herein expand on those observations through Protein structure, mutagenesis and cellular localization analyses. Structural analysis indicated that CT009 shares high level of structural similarity to RodZ, revealing the conserved orientation of two residues critical for MreB interaction. Substitutions eliminated MreB Protein interaction and partial complementation provided by CT009 in RodZ deficient Escherichia coli. Cellular localization analysis of CT009 showed uniform membrane staining in Chlamydia. This was in contrast to the localization of MreB, which was restricted to predicted septal planes. MreB localization to septal planes provides direct experimental observation for the role of MreB in cell division and supports the hypothesis that it serves as a functional replacement for FtsZ in Chlamydia.
Peter L Graumann - One of the best experts on this subject based on the ideXlab platform.
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translation elongation factor ef tu modulates filament formation of actin like MreB Protein in vitro
Journal of Molecular Biology, 2015Co-Authors: Herve Joel Defeu Soufo, Christian Reimold, Hannes Breddermann, Hans Georg Mannherz, Peter L GraumannAbstract:EF-Tu has been shown to interact with actin-like Protein MreB and to affect its localization in Escherichia coli and in Bacillus subtilis cells. We have purified YFP-MreB in an active form, which forms filaments on glass slides in vitro and was active in dynamic light-scattering assays, polymerizing in milliseconds after addition of magnesium. Purified EF-Tu enhanced the amount of MreB filaments, as seen by sedimentation assays, the speed of filament formation and the length of MreB filaments in vitro. EF-Tu had the strongest impact on MreB filaments in a 1:1 ratio, and EF-Tu co-sedimented with MreB filaments, revealing a stoichiometric interaction between both Proteins. This was supported by cross-linking assays where 1:1 species were well detectable. When expressed in E. coli cells, B. subtilis MreB formed filaments and induced the formation of co-localizing B. subtilis EF-Tu structures, indicating that MreB can direct the positioning of EF-Tu structures in a heterologous cell system. Fluorescence recovery after photobleaching analysis showed that MreB filaments have a higher turnover in B. subtilis cells than in E. coli cells, indicating different filament kinetics in homologous or heterologous cell systems. The data show that MreB can direct the localization of EF-Tu in vivo, which in turn positively affects the formation and dynamics of MreB filaments. Thus, EF-Tu is a modulator of the activity of a bacterial actin-like Protein.
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bacterial translation elongation factor ef tu interacts and colocalizes with actin like MreB Protein
Proceedings of the National Academy of Sciences of the United States of America, 2010Co-Authors: Christian Reimold, Uwe Linne, Tobias Knust, Johannes Gescher, Peter L GraumannAbstract:We show that translation initiation factor EF-Tu plays a second important role in cell shape maintenance in the bacterium Bacillus subtilis. EF-Tu localizes in a helical pattern underneath the cell membrane and colocalizes with MreB, an actin-like cytoskeletal element setting up rod cell shape. The localization of MreB and of EF-Tu is interdependent, but in contrast to the dynamic MreB filaments, EF-Tu structures are more static and may serve as tracks for MreB filaments. In agreement with this idea, EF-Tu and MreB interact in vivo and in vitro. Lowering of the EF-Tu levels had a minor effect on translation but a strong effect on cell shape and on the localization of MreB, and blocking of the function of EF-Tu in translation did not interfere with the localization of MreB, showing that, directly or indirectly, EF-Tu affects the cytoskeletal MreB structure and thus serves two important functions in a bacterium.
Kyle Evan Kemege - One of the best experts on this subject based on the ideXlab platform.
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chlamydia trachomatis Protein ct009 is a structural and functional homolog to the key morphogenesis component rodz and interacts with division septal plane localized MreB
Molecular Microbiology, 2015Co-Authors: Kyle Evan Kemege, John M Hickey, Michael L Barta, Jason R Wickstrum, Namita Ashwin Balwalli, Scott Lovell, Kevin P Battaile, Scott P HeftyAbstract:Cell division in Chlamydiae is poorly understood as apparent homologs to most conserved bacterial cell division Proteins are lacking and presence of elongation (rod shape) associated Proteins indicate non-canonical mechanisms may be employed. The rod-shape determining Protein MreB has been proposed as playing a unique role in chlamydial cell division. In other organisms, MreB is part of an elongation complex that requires RodZ for proper function. A recent study reported that the Protein encoded by ORF CT009 interacts with MreB despite low sequence similarity to RodZ. The studies herein expand on those observations through Protein structure, mutagenesis and cellular localization analyses. Structural analysis indicated that CT009 shares high level of structural similarity to RodZ, revealing the conserved orientation of two residues critical for MreB interaction. Substitutions eliminated MreB Protein interaction and partial complementation provided by CT009 in RodZ deficient Escherichia coli. Cellular localization analysis of CT009 showed uniform membrane staining in Chlamydia. This was in contrast to the localization of MreB, which was restricted to predicted septal planes. MreB localization to septal planes provides direct experimental observation for the role of MreB in cell division and supports the hypothesis that it serves as a functional replacement for FtsZ in Chlamydia.
Nitin Chaudhary - One of the best experts on this subject based on the ideXlab platform.
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interaction of MreB derived antimicrobial peptides with membranes
Biochemical and Biophysical Research Communications, 2018Co-Authors: Karabi Saikia, Nitin ChaudharyAbstract:Abstract Antimicrobial peptides are critical components of defense systems in living forms. The activity is conferred largely by the selective membrane-permeabilizing ability. In our earlier work, we derived potent antimicrobial peptides from the 9-residue long, N-terminal amphipathic helix of E. coli MreB Protein. The peptides display broad-spectrum activity, killing not only Gram-positive and Gram-negative bacteria but opportunistic fungus, Candida albicans as well. These results proved that membrane-binding stretches of bacterial Proteins could turn out to be self-harming when applied from outside. Here, we studied the membrane-binding and membrane-perturbing potential of these peptides. Steady-state tryptophan fluorescence studies with tryptophan extended peptides, WMreB1-9 and its N-terminal acetylated analog, Ac-WMreB1-9 show preferential binding to negatively-charged liposomes. Both the peptides cause permeabilization of E. coli inner and outer-membranes. Tryptophan-lacking peptides, though permeabilize the outer-membrane efficiently, little permeabilization of the inner-membrane is observed. These data attest membrane-destabilization as the mechanism of rapid bacterial killing. This study is expected to motivate the research in identifying microbes' self-sequences to combat them.
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highly potent antimicrobial peptides from n terminal membrane binding region of e coli MreB
Scientific Reports, 2017Co-Authors: Karabi Saikia, Yalavarthi Durga Sravani, Vibin Ramakrishnan, Nitin ChaudharyAbstract:Microbial pathogenesis is a serious health concern. The threat escalates as the existing conventional antimicrobials are losing their efficacy against the evolving pathogens. Peptides hold promise to be developed into next-generation antibiotics. Antimicrobial peptides adopt amphipathic structures that could selectively bind to and disrupt the microbial membranes. Interaction of Proteins with membranes is central to all living systems and we reasoned that the membrane-binding domains in microbial Proteins could be developed into efficient antimicrobials. This is an interesting approach as self-like sequences could elude the microbial strategies of degrading the antimicrobial peptides, one of the mechanisms of showing resistance to antimicrobials. We selected the 9-residue-long membrane-binding region of E. coli MreB Protein. The 9-residue peptide (C-terminal amide) and its N-terminal acetylated analog displayed broad-spectrum activity, killing Gram-negative bacteria, Gram-positive bacteria, and fungi. Extension with a tryptophan residue at the N-terminus drastically improved the activity of the peptides with lethal concentrations ≤10 μM against all the organisms tested. The tryptophan-extended peptides caused complete killing of C. albicans as well as gentamicin and methicillin resistant S. aureus at 5 μM concentration. Lipid-binding studies and electron microscopic analyses of the peptide-treated microbes suggest membrane disruption as the mechanism of killing.
Christian Reimold - One of the best experts on this subject based on the ideXlab platform.
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translation elongation factor ef tu modulates filament formation of actin like MreB Protein in vitro
Journal of Molecular Biology, 2015Co-Authors: Herve Joel Defeu Soufo, Christian Reimold, Hannes Breddermann, Hans Georg Mannherz, Peter L GraumannAbstract:EF-Tu has been shown to interact with actin-like Protein MreB and to affect its localization in Escherichia coli and in Bacillus subtilis cells. We have purified YFP-MreB in an active form, which forms filaments on glass slides in vitro and was active in dynamic light-scattering assays, polymerizing in milliseconds after addition of magnesium. Purified EF-Tu enhanced the amount of MreB filaments, as seen by sedimentation assays, the speed of filament formation and the length of MreB filaments in vitro. EF-Tu had the strongest impact on MreB filaments in a 1:1 ratio, and EF-Tu co-sedimented with MreB filaments, revealing a stoichiometric interaction between both Proteins. This was supported by cross-linking assays where 1:1 species were well detectable. When expressed in E. coli cells, B. subtilis MreB formed filaments and induced the formation of co-localizing B. subtilis EF-Tu structures, indicating that MreB can direct the positioning of EF-Tu structures in a heterologous cell system. Fluorescence recovery after photobleaching analysis showed that MreB filaments have a higher turnover in B. subtilis cells than in E. coli cells, indicating different filament kinetics in homologous or heterologous cell systems. The data show that MreB can direct the localization of EF-Tu in vivo, which in turn positively affects the formation and dynamics of MreB filaments. Thus, EF-Tu is a modulator of the activity of a bacterial actin-like Protein.
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bacterial translation elongation factor ef tu interacts and colocalizes with actin like MreB Protein
Proceedings of the National Academy of Sciences of the United States of America, 2010Co-Authors: Christian Reimold, Uwe Linne, Tobias Knust, Johannes Gescher, Peter L GraumannAbstract:We show that translation initiation factor EF-Tu plays a second important role in cell shape maintenance in the bacterium Bacillus subtilis. EF-Tu localizes in a helical pattern underneath the cell membrane and colocalizes with MreB, an actin-like cytoskeletal element setting up rod cell shape. The localization of MreB and of EF-Tu is interdependent, but in contrast to the dynamic MreB filaments, EF-Tu structures are more static and may serve as tracks for MreB filaments. In agreement with this idea, EF-Tu and MreB interact in vivo and in vitro. Lowering of the EF-Tu levels had a minor effect on translation but a strong effect on cell shape and on the localization of MreB, and blocking of the function of EF-Tu in translation did not interfere with the localization of MreB, showing that, directly or indirectly, EF-Tu affects the cytoskeletal MreB structure and thus serves two important functions in a bacterium.