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Pesquisa : D12.644.360.420 [Categoria DeCS]
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  1 / 882 MEDLINE  
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[PMID]:28755474
[Au] Autor:McKay R; Hauk P; Wu HC; Pottash AE; Shang W; Terrell J; Payne GF; Bentley WE
[Ad] Endereço:Fischell Department of Bioengineering, University of Maryland, College Park, Maryland.
[Ti] Título:Controlling localization of Escherichia coli populations using a two-part synthetic motility circuit: An accelerator and brake.
[So] Source:Biotechnol Bioeng;114(12):2883-2895, 2017 Dec.
[Is] ISSN:1097-0290
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Probiotics, whether taken as capsules or consumed in foods, have been regarded as safe for human use by regulatory agencies. Being living cells, they serve as "tunable" factories for the synthesis of a vast array of beneficial molecules. The idea of reprogramming probiotics to act as controllable factories, producing potential therapeutic molecules under user-specified conditions, represents a new and powerful concept in drug synthesis and delivery. Probiotics that serve as drug delivery vehicles pose several challenges, one being targeting (as seen with nanoparticle approaches). Here, we employ synthetic biology to control swimming directionality in a process referred to as "pseudotaxis." Escherichia coli, absent the motility regulator cheZ, swim sporadically, missing the traditional "run" in the run:tumble swimming paradigm. Upon introduction of cheZ in trans and its signal-generated upregulation, engineered bacteria can be "programmed" to swim toward the source of the chemical cue. Here, engineered cells that encounter sufficient levels of the small signal molecule pyocyanin, produce an engineered CheZ and swim with programmed directionality. By incorporating a degradation tag at the C-terminus of CheZ, the cells stop running when they exit spaces containing pyocyanin. That is, the engineered CheZ modified with a C-terminal extension derived from the putative DNA-binding transcriptional regulator YbaQ (RREERAAKKVA) is consumed by the ClpXP protease machine at a rate sufficient to "brake" the cells when pyocyanin levels are too low. Through this process, we demonstrate that over time, these engineered E. coli accumulate in pyocyanin-rich locales. We suggest that such approaches may find utility in engineering probiotics so that their beneficial functions can be focused in areas of principal benefit.
[Mh] Termos MeSH primário: Quimiotaxia/fisiologia
Proteínas de Escherichia coli/genética
Escherichia coli/fisiologia
Redes Reguladoras de Genes/genética
Melhoramento Genético/métodos
Proteínas Quimiotáticas Aceptoras de Metil/genética
Transativadores/genética
[Mh] Termos MeSH secundário: Quimiotaxia/efeitos dos fármacos
Escherichia coli/efeitos dos fármacos
Piocianina/administração & dosagem
Biologia Sintética/métodos
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Escherichia coli Proteins); 0 (Methyl-Accepting Chemotaxis Proteins); 0 (Trans-Activators); 0 (cheZ protein, E coli); 137804-82-1 (SoxS protein, E coli); 9OQM399341 (Pyocyanine)
[Em] Mês de entrada:1711
[Cu] Atualização por classe:171116
[Lr] Data última revisão:
171116
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170730
[St] Status:MEDLINE
[do] DOI:10.1002/bit.26391


  2 / 882 MEDLINE  
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[PMID]:28664727
[Au] Autor:Pedetta A; Massazza DA; Herrera Seitz MK; Studdert CA
[Ad] Endereço:Instituto de Investigaciones Biológicas, Universidad Nacional de Mar del Plata-CONICET , Mar del Plata, Buenos Aires, Argentina.
[Ti] Título:Mutational Replacements at the "Glycine Hinge" of the Escherichia coli Chemoreceptor Tsr Support a Signaling Role for the C-Helix Residue.
[So] Source:Biochemistry;56(29):3850-3862, 2017 Jul 25.
[Is] ISSN:1520-4995
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Bacterial chemoreceptors are dimeric membrane proteins that transmit signals from a periplasmic ligand-binding domain to the interior of the cells. The highly conserved cytoplasmic domain consists of a long hairpin that in the dimer forms a four-helix coiled-coil bundle. The central region of the bundle couples changes in helix packing that occur in the membrane proximal region to the signaling tip, controlling the activity of an associated histidine kinase. This subdomain contains certain glycine residues that are postulated to form a hinge in chemoreceptors from enteric bacteria and have been largely postulated to play a role in the coupling mechanism, and/or in the formation of higher-order chemoreceptor assemblies. In this work, we directly assessed the importance of the "glycine hinge" by obtaining nonfunctional replacements at each of its positions in the Escherichia coli serine receptor Tsr and characterizing them. Our results indicate that, rather than being essential for proper receptor-receptor interaction, the "glycine hinge" residues are involved in the ability of the receptor to switch between different signaling states. Mainly, the C-helix residue G439 has a key role in shifting the equilibrium toward a kinase-activating conformation. However, we found second-site mutations that restore the chemotactic proficiency of some of the "glycine hinge" mutants, suggesting that a complete hinge is not strictly essential. Rather, glycine residues seem to favor the coupling activity that relies on some other structural features of the central subdomain.
[Mh] Termos MeSH primário: Escherichia coli K12/química
Proteínas Quimiotáticas Aceptoras de Metil/química
Transdução de Sinais
[Mh] Termos MeSH secundário: Substituição de Aminoácidos
Escherichia coli K12/genética
Proteínas Quimiotáticas Aceptoras de Metil/genética
Mutação de Sentido Incorreto
Estrutura Secundária de Proteína
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Methyl-Accepting Chemotaxis Proteins); 0 (tsr protein, E coli)
[Em] Mês de entrada:1707
[Cu] Atualização por classe:171116
[Lr] Data última revisão:
171116
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170701
[St] Status:MEDLINE
[do] DOI:10.1021/acs.biochem.7b00455


  3 / 882 MEDLINE  
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[PMID]:28542702
[Au] Autor:Baron S; Eisenbach M
[Ad] Endereço:Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel.
[Ti] Título:CheY acetylation is required for ordinary adaptation time in Escherichia coli chemotaxis.
[So] Source:FEBS Lett;591(13):1958-1965, 2017 Jul.
[Is] ISSN:1873-3468
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Recent studies demonstrated the dependence of speed adaptation in Escherichia coli on acetylation of the chemotaxis signaling molecule CheY. Here, we examined whether CheY acetylation is involved in chemotactic adaptation. A mutant lacking the acetylating enzyme acetyl-CoA synthetase (Acs) requires more time to adapt to attractant stimulation, and vice versa to repellent stimulation. This effect is avoided by conditions that favor production of acetyl-CoA, thus enabling Acs-independent CheY autoacetylation, or reversed by expressing Acs from a plasmid. These findings suggest that CheY should be acetylated for ordinary adaptation time, and that the function of this acetylation in adaptation is to enable the motor to shift its rotation to clockwise. We further identify the enzyme phosphotransacetylase as a third deacetylase of CheY in E. coli.
[Mh] Termos MeSH primário: Adaptação Fisiológica
Quimiotaxia
Escherichia coli/citologia
Escherichia coli/metabolismo
Proteínas Quimiotáticas Aceptoras de Metil/metabolismo
[Mh] Termos MeSH secundário: Acetilcoenzima A/metabolismo
Acetilação
Escherichia coli/fisiologia
[Pt] Tipo de publicação:LETTER
[Nm] Nome de substância:
0 (Methyl-Accepting Chemotaxis Proteins); 0 (cheY protein, E coli); 72-89-9 (Acetyl Coenzyme A)
[Em] Mês de entrada:1708
[Cu] Atualização por classe:171116
[Lr] Data última revisão:
171116
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170526
[St] Status:MEDLINE
[do] DOI:10.1002/1873-3468.12699


  4 / 882 MEDLINE  
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[PMID]:28440031
[Au] Autor:Beyersdorf MS; Sircar R; Lookadoo DB; Bottone CJ; Lynch MJ; Crane BR; Halkides CJ
[Ad] Endereço:Department of Chemistry and Biochemistry, The University of North Carolina Wilmington, Wilmington, North Carolina, 28403.
[Ti] Título:Production, characterization, and assessment of a stable analog of the response regulator CheY-phosphate from Thermotoga maritima.
[So] Source:Protein Sci;26(8):1547-1554, 2017 Aug.
[Is] ISSN:1469-896X
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Phosphorylation of CheY promotes association with the flagellar motor and ultimately controls the directional bias of the motor. However, biochemical studies of activated CheY-phosphate have been challenging due to the rapid hydrolysis of the aspartyl-phosphate in vitro. An inert analog of Tm CheY-phosphate, phosphono-CheY, was synthesized by chemical modification and purified by cation-exchange chromatography. Changes in HPLC retention times, chemical assays for phosphate and free thiol, and mass spectrometry experiments demonstrate modification of Cys54 with a phosphonomethyl group. Additionally, a crystal structure showed electron density for the phosphonomethyl group at Cys54, consistent with a modification at that position. Subsequent biochemical experiments confirmed that protein crystals were phosphono-CheY. Isothermal titration calorimetry and fluorescence polarization binding assays demonstrated that phosphono-CheY bound a peptide derived from FliM, a native partner of CheY-phosphate, with a dissociation constant of ∼29 µM, at least sixfold more tightly than unmodified CheY. Taken together these results suggest that Tm phosphono-CheY is a useful and unique analog of Tm CheY-phosphate.
[Mh] Termos MeSH primário: Proteínas de Bactérias/química
Proteínas Quimiotáticas Aceptoras de Metil/química
Organofosfonatos/química
Peptídeos/química
Thermotoga maritima/química
[Mh] Termos MeSH secundário: Sequência de Aminoácidos
Ácido Aspártico/análogos & derivados
Ácido Aspártico/química
Ácido Aspártico/metabolismo
Proteínas de Bactérias/genética
Proteínas de Bactérias/metabolismo
Sítios de Ligação
Quimiotaxia/fisiologia
Clonagem Molecular
Cristalografia por Raios X
Escherichia coli/genética
Escherichia coli/metabolismo
Flagelos/química
Flagelos/metabolismo
Expressão Gênica
Cinética
Proteínas Quimiotáticas Aceptoras de Metil/genética
Proteínas Quimiotáticas Aceptoras de Metil/metabolismo
Modelos Moleculares
Organofosfonatos/metabolismo
Peptídeos/genética
Peptídeos/metabolismo
Fosforilação
Ligação Proteica
Conformação Proteica em alfa-Hélice
Conformação Proteica em Folha beta
Engenharia de Proteínas
Domínios e Motivos de Interação entre Proteínas
Proteínas Recombinantes/química
Proteínas Recombinantes/genética
Proteínas Recombinantes/metabolismo
Thermotoga maritima/genética
Thermotoga maritima/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (Methyl-Accepting Chemotaxis Proteins); 0 (Organophosphonates); 0 (Peptides); 0 (Recombinant Proteins); 134548-59-7 (FliM protein, Bacteria); 22138-53-0 (beta-aspartyl phosphate); 30KYC7MIAI (Aspartic Acid)
[Em] Mês de entrada:1708
[Cu] Atualização por classe:171116
[Lr] Data última revisão:
171116
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170426
[St] Status:MEDLINE
[do] DOI:10.1002/pro.3180


  5 / 882 MEDLINE  
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[PMID]:28425142
[Au] Autor:Pan W; Dahlquist FW; Hazelbauer GL
[Ad] Endereço:Department of Biochemistry, University of Missouri, Columbia, Missouri, 65211.
[Ti] Título:Signaling complexes control the chemotaxis kinase by altering its apparent rate constant of autophosphorylation.
[So] Source:Protein Sci;26(8):1535-1546, 2017 Aug.
[Is] ISSN:1469-896X
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Autophosphorylating histidine kinase CheA is central to signaling in bacterial chemotaxis. The kinase donates its phosphoryl group to two response regulators, CheY that controls flagellar rotation and thus motility and CheB, crucial for sensory adaptation. As measured by coupled CheY phosphorylation, incorporation into signaling complexes activates the kinase ∼1000-fold and places it under control of chemoreceptors. By the same assay, receptors modulate kinase activity ∼100-fold as a function of receptor ligand occupancy and adaptational modification. These changes are the essence of chemotactic signaling. Yet, the enzymatic properties affected by incorporation into signaling complexes, by chemoreceptor ligand binding or by receptor adaptational modification are largely undefined. To investigate, we performed steady-state kinetic analysis of autophosphorylation using a liberated kinase phosphoryl-accepting domain, characterizing kinase alone, in isolated core signaling complexes and in small arrays of core complexes assembled in vitro with receptors contained in isolated native membranes. Autophosphorylation in signaling complexes was measured as a function of ligand occupancy and adaptational modification. Activation by incorporation into signaling complexes and modulation in complexes by ligand occupancy and adaptational modification occurred largely via changes in the apparent catalytic rate constant (k ). Changes in the autophosphorylation k accounted for most of the ∼1000-fold kinase activation in signaling complexes observed for coupled CheY phosphorylation, and the ∼100-fold inhibition by ligand occupancy or modulation by adaptational modification. Our results indicate no more than a minor role in kinase control for simple sequestration of the autophosphorylation substrate. Instead they indicate direct effects on the active site.
[Mh] Termos MeSH primário: Ácido Aspártico/metabolismo
Proteínas de Bactérias/metabolismo
Proteínas de Escherichia coli/metabolismo
Escherichia coli/enzimologia
Histidina Quinase/metabolismo
Proteínas Quimiotáticas Aceptoras de Metil/metabolismo
Receptores de Superfície Celular/metabolismo
[Mh] Termos MeSH secundário: Motivos de Aminoácidos
Proteínas de Bactérias/genética
Sítios de Ligação
Quimiotaxia/fisiologia
Escherichia coli/genética
Proteínas de Escherichia coli/genética
Expressão Gênica
Histidina Quinase/genética
Cinética
Ligantes
Proteínas Quimiotáticas Aceptoras de Metil/genética
Fosforilação
Ligação Proteica
Domínios Proteicos
Multimerização Proteica
Receptores de Superfície Celular/genética
Proteínas Recombinantes/genética
Proteínas Recombinantes/metabolismo
Transdução de Sinais
Especificidade por Substrato
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (Escherichia coli Proteins); 0 (Ligands); 0 (Methyl-Accepting Chemotaxis Proteins); 0 (Receptors, Cell Surface); 0 (Recombinant Proteins); 0 (Tar protein, E coli); 0 (cheY protein, E coli); 139076-03-2 (CheB protein, Bacteria); 30KYC7MIAI (Aspartic Acid); EC 2.7.13.1 (Histidine Kinase); EC 2.7.13.3 (cheA protein, E coli)
[Em] Mês de entrada:1708
[Cu] Atualização por classe:171116
[Lr] Data última revisão:
171116
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170421
[St] Status:MEDLINE
[do] DOI:10.1002/pro.3179


  6 / 882 MEDLINE  
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[PMID]:28409190
[Au] Autor:Salah Ud-Din AIM; Roujeinikova A
[Ad] Endereço:Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, VIC, Australia.
[Ti] Título:Methyl-accepting chemotaxis proteins: a core sensing element in prokaryotes and archaea.
[So] Source:Cell Mol Life Sci;74(18):3293-3303, 2017 Sep.
[Is] ISSN:1420-9071
[Cp] País de publicação:Switzerland
[La] Idioma:eng
[Ab] Resumo:Chemotaxis is the directed motility by means of which microbes sense chemical cues and relocate towards more favorable environments. Methyl-accepting chemotaxis proteins (MCPs) are the most common receptors in bacteria and archaea. They are arranged as trimers of dimers that, in turn, form hexagonal arrays in the cytoplasmic membrane or in the cytoplasm. Several different classes of MCPs have been identified according to their ligand binding region and membrane topology. MCPs have been further classified based on the length and sequence conservation of their cytoplasmic domains. Clusters of membrane-embedded MCPs often localize to the poles of the cell, whereas cytoplasmic MCPs can be targeted to the poles or distributed throughout the cell body. MCPs play an important role in cell survival, pathogenesis, and biodegradation. Bacterial adaptation to diverse environmental conditions promotes diversity among the MCPs. This review summarizes structure, classification, and structure-activity relationship of the known MCP receptors, with a brief overview of the signal transduction mechanisms in bacteria and archaea.
[Mh] Termos MeSH primário: Archaea/metabolismo
Proteínas Quimiotáticas Aceptoras de Metil/metabolismo
Células Procarióticas/metabolismo
[Mh] Termos MeSH secundário: Archaea/classificação
Quimiotaxia
Proteínas de Membrana/química
Proteínas de Membrana/metabolismo
Proteínas Quimiotáticas Aceptoras de Metil/química
Células Procarióticas/classificação
Domínios Proteicos
Transdução de Sinais
Relação Estrutura-Atividade
[Pt] Tipo de publicação:JOURNAL ARTICLE; REVIEW
[Nm] Nome de substância:
0 (Membrane Proteins); 0 (Methyl-Accepting Chemotaxis Proteins)
[Em] Mês de entrada:1708
[Cu] Atualização por classe:171116
[Lr] Data última revisão:
171116
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170415
[St] Status:MEDLINE
[do] DOI:10.1007/s00018-017-2514-0


  7 / 882 MEDLINE  
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[PMID]:28402881
[Au] Autor:Sukomon N; Widom J; Borbat PP; Freed JH; Crane BR
[Ad] Endereço:Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York.
[Ti] Título:Stability and Conformation of a Chemoreceptor HAMP Domain Chimera Correlates with Signaling Properties.
[So] Source:Biophys J;112(7):1383-1395, 2017 Apr 11.
[Is] ISSN:1542-0086
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:HAMP domains are dimeric, four-helix bundles that transduce conformational signals in bacterial receptors. Genetic studies of the Escherichia coli serine receptor (Tsr) provide an opportunity to understand HAMP conformational behavior in terms of functional output. To increase its stability, the Tsr HAMP domain was spliced into a poly-HAMP unit from the Pseudomonas aeruginosa Aer2 receptor. Within the chimera, the Tsr HAMP undergoes a thermal melting transition at a temperature much lower than that of the Aer2 HAMP domains. Pulse-dipolar electron spin resonance spectroscopy and site-specific spin-labeling confirm that the Tsr HAMP maintains a four-helix bundle. Pulse-dipolar electron spin resonance spectroscopy was also used to study three well-characterized HAMP mutational phenotypes: those that cause flagella rotation that is counterclockwise (CCW) A and kinase-off; CCW B and also kinase-off; and, clockwise (CW) and kinase-on. Conformational properties of the three HAMP variants support a biphasic model of dynamic bundle stability, but also indicate distinct conformational changes within the helix bundle. Functional kinase-on (CW) and kinase-off (CCW A) states differ by concerted changes in the positions of spin-label sites at the base of the bundle. Opposite shifts in the subunit separation distances of neighboring residues at the C-termini of the α1 and α2 helices are consistent with a helix scissors motion or a gearbox rotational model of HAMP activation. In the drastic kinase-off lesion of CCW B, the α1 helices unfold and the α2 helices form a tight two-helix coiled-coil. The substitution of a critical residue in the Tsr N-terminal linker or control cable reduces conformational heterogeneity at the N-terminus of α1 but does not affect structure at the C-terminus of α2. Overall, the data suggest that transitions from on- to off-states involve decreased motional amplitudes of the Tsr HAMP coupled with helix rotations and movements toward a two-helix packing mode.
[Mh] Termos MeSH primário: Proteínas Quimiotáticas Aceptoras de Metil/química
Proteínas Recombinantes de Fusão/química
Transdução de Sinais
[Mh] Termos MeSH secundário: Substituição de Aminoácidos
Aminoácidos/química
Proteínas de Bactérias/química
Proteínas de Bactérias/metabolismo
Espectroscopia de Ressonância de Spin Eletrônica
Proteínas Quimiotáticas Aceptoras de Metil/metabolismo
Mutação
Domínios Proteicos
Estabilidade Proteica
Estrutura Secundária de Proteína
Pseudomonas aeruginosa/metabolismo
Proteínas Recombinantes de Fusão/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Amino Acids); 0 (Bacterial Proteins); 0 (Methyl-Accepting Chemotaxis Proteins); 0 (Recombinant Fusion Proteins); 0 (tsr protein, E coli)
[Em] Mês de entrada:1704
[Cu] Atualização por classe:171116
[Lr] Data última revisão:
171116
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170414
[St] Status:MEDLINE


  8 / 882 MEDLINE  
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[PMID]:28380286
[Au] Autor:Houwman JA; van Mierlo CPM
[Ad] Endereço:Laboratory of Biochemistry, Wageningen University and Research, The Netherlands.
[Ti] Título:Folding of proteins with a flavodoxin-like architecture.
[So] Source:FEBS J;284(19):3145-3167, 2017 Oct.
[Is] ISSN:1742-4658
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:The flavodoxin-like fold is a protein architecture that can be traced back to the universal ancestor of the three kingdoms of life. Many proteins share this α-ß parallel topology and hence it is highly relevant to illuminate how they fold. Here, we review experiments and simulations concerning the folding of flavodoxins and CheY-like proteins, which share the flavodoxin-like fold. These polypeptides tend to temporarily misfold during unassisted folding to their functionally active forms. This susceptibility to frustration is caused by the more rapid formation of an α-helix compared to a ß-sheet, particularly when a parallel ß-sheet is involved. As a result, flavodoxin-like proteins form intermediates that are off-pathway to native protein and several of these species are molten globules (MGs). Experiments suggest that the off-pathway species are of helical nature and that flavodoxin-like proteins have a nonconserved transition state that determines the rate of productive folding. Folding of flavodoxin from Azotobacter vinelandii has been investigated extensively, enabling a schematic construction of its folding energy landscape. It is the only flavodoxin-like protein of which cotranslational folding has been probed. New insights that emphasize differences between in vivo and in vitro folding energy landscapes are emerging: the ribosome modulates MG formation in nascent apoflavodoxin and forces this polypeptide toward the native state.
[Mh] Termos MeSH primário: Azotobacter vinelandii/genética
Escherichia coli/genética
Flavodoxina/química
Proteínas Quimiotáticas Aceptoras de Metil/química
Isoformas de Proteínas/química
[Mh] Termos MeSH secundário: Azotobacter vinelandii/metabolismo
Escherichia coli/metabolismo
Flavodoxina/genética
Flavodoxina/metabolismo
Expressão Gênica
Proteínas Quimiotáticas Aceptoras de Metil/genética
Proteínas Quimiotáticas Aceptoras de Metil/metabolismo
Modelos Moleculares
Biossíntese de Proteínas
Conformação Proteica em alfa-Hélice
Conformação Proteica em Folha beta
Dobramento de Proteína
Isoformas de Proteínas/genética
Isoformas de Proteínas/metabolismo
Termodinâmica
[Pt] Tipo de publicação:JOURNAL ARTICLE; REVIEW
[Nm] Nome de substância:
0 (Flavodoxin); 0 (Methyl-Accepting Chemotaxis Proteins); 0 (Protein Isoforms); 0 (cheY protein, E coli)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171116
[Lr] Data última revisão:
171116
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170406
[St] Status:MEDLINE
[do] DOI:10.1111/febs.14077


  9 / 882 MEDLINE  
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[PMID]:28215934
[Au] Autor:Lai RZ; Gosink KK; Parkinson JS
[Ad] Endereço:Biology Department, University of Utah, Salt Lake City, UT 84112, USA.
[Ti] Título:Signaling Consequences of Structural Lesions that Alter the Stability of Chemoreceptor Trimers of Dimers.
[So] Source:J Mol Biol;429(6):823-835, 2017 Mar 24.
[Is] ISSN:1089-8638
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Residues E402 and R404 of the Escherichia coli serine chemoreceptor, Tsr, appear to form a salt bridge that spans the interfaces between neighboring dimers in the Tsr trimer of dimers, a key structural component of receptor core signaling complexes. To assess their functional roles, we constructed full sets of single amino acid replacement mutants at E402 and R404 and characterized their signaling behaviors with a suite of in vivo assays. Our results indicate that the E402 and R404 residues of Tsr play their most critical signaling roles at their inner locations near the trimer axis where they likely participate in stabilizing the trimer-of-dimer packing and the kinase-ON state of core signaling complexes. Mutant receptors with a variety of side-chain replacements still accessed both the ON and OFF signaling states, suggesting that core signaling complexes produce kinase activity over a range of receptor conformations and dynamic motions. Similarly, the kinase-OFF state may not be a discrete conformation but rather a range of structures outside the range of those suitable for kinase activation. Consistent with this idea, some structural lesions at both E402 and R404 produced signaling behaviors that are not compatible with discrete two-state models of core complex signaling states. Those lesions might stabilize intermediate receptor conformations along the OFF-ON energy landscape. Amino acid replacements produced different constellations of signaling defects at each residue, indicating that they play distinct structure-function roles. R404, but not E402, was critical for high signal cooperativity in the receptor array.
[Mh] Termos MeSH primário: Escherichia coli/genética
Escherichia coli/fisiologia
Proteínas Quimiotáticas Aceptoras de Metil/genética
Proteínas Quimiotáticas Aceptoras de Metil/metabolismo
Proteínas Mutantes/genética
Proteínas Mutantes/metabolismo
Transdução de Sinais
[Mh] Termos MeSH secundário: Substituição de Aminoácidos
Análise Mutacional de DNA
Mutagênese Sítio-Dirigida
Fosforilação
Multimerização Proteica
Processamento de Proteína Pós-Traducional
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Methyl-Accepting Chemotaxis Proteins); 0 (Mutant Proteins); 0 (tsr protein, E coli)
[Em] Mês de entrada:1707
[Cu] Atualização por classe:171116
[Lr] Data última revisão:
171116
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170221
[St] Status:MEDLINE


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[PMID]:27802580
[Au] Autor:Foster CA; West AH
[Ad] Endereço:Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma.
[Ti] Título:Use of restrained molecular dynamics to predict the conformations of phosphorylated receiver domains in two-component signaling systems.
[So] Source:Proteins;85(1):155-176, 2017 Jan.
[Is] ISSN:1097-0134
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Two-component signaling (TCS) is the primary means by which bacteria, as well as certain plants and fungi, respond to external stimuli. Signal transduction involves stimulus-dependent autophosphorylation of a sensor histidine kinase and phosphoryl transfer to the receiver domain of a downstream response regulator. Phosphorylation acts as an allosteric switch, inducing structural and functional changes in the pathway's components. Due to their transient nature, phosphorylated receiver domains are challenging to characterize structurally. In this work, we provide a methodology for simulating receiver domain phosphorylation to predict conformations that are nearly identical to experimental structures. Using restrained molecular dynamics, phosphorylated conformations of receiver domains can be reliably sampled on nanosecond timescales. These simulations also provide data on conformational dynamics that can be used to identify regions of functional significance related to phosphorylation. We first validated this approach on several well-characterized receiver domains and then used it to compare the upstream and downstream components of the fungal Sln1 phosphorelay. Our results demonstrate that this technique provides structural insight, obtained in the absence of crystallographic or NMR information, regarding phosphorylation-induced conformational changes in receiver domains that regulate the output of their associated signaling pathway. To our knowledge, this is the first time such a protocol has been described that can be broadly applied to TCS proteins for predictive purposes. Proteins 2016; 85:155-176. © 2016 Wiley Periodicals, Inc.
[Mh] Termos MeSH primário: Proteínas de Bactérias/química
Proteínas de Escherichia coli/química
Peptídeos e Proteínas de Sinalização Intracelular/química
Proteínas Quimiotáticas Aceptoras de Metil/química
Modelos Estatísticos
Simulação de Dinâmica Molecular
Proteínas Quinases/química
Proteínas de Saccharomyces cerevisiae/química
[Mh] Termos MeSH secundário: Bacillus subtilis/genética
Bacillus subtilis/metabolismo
Proteínas de Bactérias/metabolismo
Sítios de Ligação
Escherichia coli/genética
Escherichia coli/metabolismo
Proteínas de Escherichia coli/metabolismo
Expressão Gênica
Peptídeos e Proteínas de Sinalização Intracelular/metabolismo
Proteínas Quimiotáticas Aceptoras de Metil/metabolismo
Fosforilação
Ligação Proteica
Domínios e Motivos de Interação entre Proteínas
Proteínas Quinases/metabolismo
Estrutura Secundária de Proteína
Saccharomyces cerevisiae/genética
Saccharomyces cerevisiae/metabolismo
Proteínas de Saccharomyces cerevisiae/metabolismo
Transdução de Sinais
Sinorhizobium meliloti/genética
Sinorhizobium meliloti/metabolismo
Termodinâmica
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (Escherichia coli Proteins); 0 (Intracellular Signaling Peptides and Proteins); 0 (Methyl-Accepting Chemotaxis Proteins); 0 (PhoP protein, E coli); 0 (Saccharomyces cerevisiae Proteins); 0 (Spo0F protein, Bacillus subtilis); 0 (cheY protein, E coli); 136253-38-8 (FixJ protein, Bacteria); EC 2.7.- (Protein Kinases); EC 2.7.13.3 (SLN1 protein, S cerevisiae)
[Em] Mês de entrada:1707
[Cu] Atualização por classe:171116
[Lr] Data última revisão:
171116
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161102
[St] Status:MEDLINE
[do] DOI:10.1002/prot.25207



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