A5017156629- Legume Nitrogen Fixing Symbiosis
- Bacterial Genetics and Biotechnology
- Plant nutrient uptake and metabolism
- RNA and protein synthesis mechanisms
- Advanced Cellulose Research Studies
- Polysaccharides and Plant Cell Walls
- Bacteriophages and microbial interactions
- Enzyme Structure and Function
- Biofuel production and bioconversion
- Protein Structure and Dynamics
- Genomics and Phylogenetic Studies
- Microbial Community Ecology and Physiology
- Plant Micronutrient Interactions and Effects
- RNA modifications and cancer
- ATP Synthase and ATPases Research
- Muscle Physiology and Disorders
- Light effects on plants
- Telomeres, Telomerase, and Senescence
- Carcinogens and Genotoxicity Assessment
- Microbial Metabolites in Food Biotechnology
- DNA and Nucleic Acid Chemistry
- Biochemical and Molecular Research
- Plant responses to water stress
- Wastewater Treatment and Nitrogen Removal
- Pediatric Hepatobiliary Diseases and Treatments
Pennsylvania State University
2011-2024
Park University
2014-2022
NIST Center for Neutron Research
2005
Lawrence Berkeley National Laboratory
2005
Argonne National Laboratory
2005
University of California, Berkeley
2005
University of Georgia
1994
Harvard University
1985-1989
Massachusetts General Hospital
1985-1987
McMaster University
1978
We report that the ntrB and ntrC proteins of Bradyrhizobium sp. [Parasponia] strain RP501 share homology with other regulatory proteins. There is extensive conservation C-terminal regions between products ntrB; Klebsiella pneumoniae Escherichia coli envZ, cpxA, phoR; Agrobacterium tumefaciens virA; and, to a lesser extent, E. cheA. also N-terminal ntrC; K. ompR, sfrA, phoB, cheY cheB; Salmonella typhimurium cheB cheY; Bacillus subtilis spoOA spoOF; A. virG. propose these genes comprise...
Using single-molecule fluorescence resonance energy transfer, we have defined bacterial RNA polymerase (RNAP) clamp conformation at each step in transcription initiation and elongation. We find that the predominantly is open free RNAP early intermediates but closes upon formation of a catalytically competent complex remains closed during initial show four inhibitors interfere with opening. propose opening allows DNA to be loaded into unwound active-center cleft, loading unwinding trigger...
Abstract A six-lobed membrane spanning cellulose synthesis complex (CSC) containing multiple synthase (CESA) glycosyltransferases mediates microfibril formation. The number of CESAs in the CSC has been debated for decades light changing estimates diameter smallest formed from β-1,4 glucan chains synthesized by one CSC. We obtained more direct evidence through generating improved transmission electron microscopy (TEM) images and image averages rosette-type CSC, revealing frequent...
We report the identification and cloning of an ntrA-like (glnF rpoN) gene Rhizobium meliloti show that R. ntrA product (NtrA) is required for C4-dicarboxylate transport as well nitrate assimilation symbiotic nitrogen fixation. DNA sequence analysis showed NtrA 38% homologous with Klebsiella pneumoniae NtrA. Subcloning complementation suggested promoter lies within 125 base pairs initiation codon may be constitutively expressed.
Transcription by σ 54 RNA polymerase depends on activators that contain ATPase domains of the AAA + class. These activators, which are often response regulators two-component signal transduction systems, remodel so it can form open complexes at promoters. Here, we report first crystal structures domain an activator, NtrC1 protein from extreme thermophile Aquifex aeolicus . This alone, is active, crystallized as a ring-shaped heptamer. The carrying both and adjacent receiver domains,...
We show here that Rhizobium meliloti, the nitrogen-fixing endosymbiont of alfalfa (Medicago sativa), has a regulatory gene is structurally homologous to previously characterized ntrC genes in enteric bacteria. DNA sequence analysis showed R. meliloti sequenced from Klebsiella pneumoniae and Bradyrhizobium sp. (Parasponia) an ntrB-like situated directly upstream ntrC. Similar its counterparts K. Escherichia coli, expressed when cells are grown nitrogen-limiting media. In addition, required...
A cellulose synthesis complex with a "rosette" shape is responsible for of chains and their assembly into microfibrils within the cell walls land plants charophyte algal progenitors. The number synthase proteins in this large multisubunit transmembrane protein microfibril have been debated many years. This work reports low resolution structure catalytic domain CESA1 from Arabidopsis (Arabidopsis thaliana; AtCESA1CatD) determined by small-angle scattering techniques provides first...
Significance Cellulose is an abundant natural polymer synthesized primarily by vascular plants in which it forms the load-bearing component of cell wall. It a linear glucose molecules membrane-embedded cellulose synthases that couple synthesis with its secretion across plasma membrane. Plants express multiple synthase isoforms are organized into large macromolecular assemblies varying composition likely responsible for aligning strands microfibrils. Here we show recombinantly expressed and...
The production of fuels from biomass is categorized as first-, second- or third-generation depending upon the source raw materials, either food crops, lignocellulosic material, algal biomass, respectively. Thus far, emphasis has been on using crops creating several environmental problems. To overcome these problems, there a shift toward bioenergy non-food sources. Algae, which store high amounts carbohydrates, are potential producer materials for sustainable bioethanol. Algae their...
In two-component signal transduction, an input triggers phosphorylation of receiver domains that regulate the status output modules. One such module is AAA+ ATPase domain in bacterial enhancer-binding proteins remodel σ 54 form RNA polymerase. We report X-ray solution scattering and electron microscopy structures activated, full-length nitrogen-regulatory protein C (NtrC) showing a novel mechanism for regulation assembly via juxtaposition ring. Accompanying hydrolysis cycle required...
Complementation of Rhizobium leguminosarum dct mutants with a cosmid bank yielded meliloti homologs the dctA, dctB, and dctD genes. The genes dctB are thought to form two-component system which responds presence C4-dicarboxylates regulate expression transport protein encoded by dctA. DNA sequence analysis showed that coding intergenic regions, including putative binding sites for sigma 54-RNA polymerase, were highly conserved between these two species. Mutation R. it was not essential...
Cellulose, the major component of plant cell walls, can be converted to bioethanol and is thus highly studied. In plants, cellulose produced by synthase, a processive family-2 glycosyltransferase. individual β-1,4-glucan chains polymerized CesA are assembled into microfibrils that frequently bundled macrofibrils. An in vitro system which synthesized fibrils would facilitate detailed study this process. Here, we report heterologous expression partial purification His-tagged CesA5 from...
Bacterial crystalline cellulose is used in biomedical and industrial applications, but the molecular mechanisms of synthesis are unclear. Unlike most bacteria, which make non-crystalline cellulose, Gluconacetobacter hansenii extrudes profuse amounts cellulose. Its synthase (AcsA) exists as a complex with accessory protein AcsB, forming 'terminal complex' (TC) that has been visualized by freeze-fracture TEM at base ribbons The catalytic AcsAB embedded cytoplasmic membrane. C-terminal portion...
The dctD gene product (DCTD) activates transcription from dctA by the sigma 54-holoenzyme form of RNA polymerase in Rhizobium meliloti. We have purified a constitutively active R. meliloti DCTD that lacks 142 amino acid residues N terminus (designated DCTDL143). Purified DCTDL143 recognized DCTD-binding sites at promoter region and catalyzed isomerization closed complexes between to open complexes. Like related 54-dependent activators NTRC NIFA, purine nucleoside triphosphate with...
Previous studies have shown that growth hormone promotes the differentiation of preadipose 3T3 cells into adipose cells. This action is not mediated by insulin-like factor 1 (IGF-1), but exerted directly on preadipocytes. In order to determine whether other mesenchymal cell types, we examined its effect formation multinucleated muscle from myoblasts. Clone mu cells, generated line 10T1/2 treatment with azacytidine, were known be capable undergoing myogenesis. When these cultivated in a...
Cellulose, the most abundant biopolymer, is a central source for renewable energy and functionalized materials.
Abstract. Irradiation of Dulbecco's modified Eagle's tissue culture medium with “Daylight,”“Special Blue,” or “Bilirubin” fluorescent light produces photoproducts lethal to human cells. Killing is abolished when (1) riboflavin, (2) tryptophan and tyrosine, (3) tyrosine are deleted from prior irradiation any the above lamps. Toxic also formed buffered salt solutions containing (a) riboflavin tryptophan, (b) (c) exposed these sources.
It is largely unknown how the typical homomeric ring geometry of ATPases associated with various cellular activities enables them to perform mechanical work. Small-angle solution X-ray scattering, crystallography, and electron microscopy (EM) reconstructions revealed that partial ATP occupancy caused heptameric closed bacterial enhancer-binding protein (bEBP) NtrC1 rearrange into a hexameric split striking asymmetry. The highly conserved functionally crucial GAFTGA loops responsible for...
A Crystallogral structure is described for the Mg2+-BeF3--bound receiver domain of Sinorhizobium meliloti DctD bearing amino acid substitution E121K. Differences between apo- and ligand-bound active sites are similar to those reported other domains. However, off on states characterized by dramatically different dimeric structures, which supports following hypothesis signal transduction. In state, coiled-coil linker form a dimer that inhibits oligomerization AAA+ ATPase domain. this...