The higher plant PII signal transduction protein: structure, function and properties

2007 ◽  
Vol 85 (6) ◽  
pp. 533-537 ◽  
Author(s):  
Greg B.G. Moorhead ◽  
Tony S. Ferrar ◽  
Yan M. Chen ◽  
Yutaka Mizuno ◽  
Catherine S. Smith ◽  
...  
Keyword(s):  
Higher Plants ◽  
Structural Features ◽  
Signaling Proteins ◽  
Higher Plant ◽  
Binding Partner ◽  
Signal Transduction Protein ◽  
Metabolic Sensor ◽  
Nitrogen Sensing ◽  
Over 40 Years

The PII carbon/nitrogen sensing protein was discovered in Escherichia coli (Migula 1895) Castellani and Chalmers 1919, over 40 years ago. Orthologues have been discovered in three kingdoms of life making it one of the most ancient and conserved signaling proteins known. Recent advances in the field have established its primary binding partner in plants as N-acetyl glutamate kinase and the crystal structure has revealed features unique to plants that likely contribute to its function in vivo. Here, we review the properties, function, and novel structural features of this chloroplast-localized metabolic sensor of higher plants.

scholarly journals Modeling of Protein–Protein Interactions in Cytokinin Signal Transduction

2019 ◽  
Vol 20 (9) ◽  
pp. 2096 ◽  
Author(s):  
Dmitry V. Arkhipov ◽  
Sergey N. Lomin ◽  
Yulia A. Myakushina ◽  
Ekaterina M. Savelieva ◽  
Dmitry I. Osolodkin ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Hot Spots ◽  
Protein Complexes ◽  
Structural Features ◽  
Signaling Proteins ◽  
In Planta ◽  
Protein Protein Interactions ◽  
Response Regulators ◽  
Protein Surfaces

The signaling of cytokinins (CKs), classical plant hormones, is based on the interaction of proteins that constitute the multistep phosphorelay system (MSP): catalytic receptors—sensor histidine kinases (HKs), phosphotransmitters (HPts), and transcription factors—response regulators (RRs). Any CK receptor was shown to interact in vivo with any of the studied HPts and vice versa. In addition, both of these proteins tend to form a homodimer or a heterodimeric complex with protein-paralog. Our study was aimed at explaining by molecular modeling the observed features of in planta protein–protein interactions, accompanying CK signaling. For this purpose, models of CK-signaling proteins’ structure from Arabidopsis and potato were built. The modeled interaction interfaces were formed by rather conserved areas of protein surfaces, complementary in hydrophobicity and electrostatic potential. Hot spots amino acids, determining specificity and strength of the interaction, were identified. Virtual phosphorylation of conserved Asp or His residues affected this complementation, increasing (Asp-P in HK) or decreasing (His-P in HPt) the affinity of interacting proteins. The HK–HPt and HPt–HPt interfaces overlapped, sharing some of the hot spots. MSP proteins from Arabidopsis and potato exhibited similar properties. The structural features of the modeled protein complexes were consistent with the experimental data.

scholarly journals Rolling-circle replication of mitochondrial DNA in the higher plant Chenopodium album (L.).

1996 ◽  
Vol 16 (11) ◽  
pp. 6285-6294 ◽  
Author(s):  
S Backert ◽  
P Dörfel ◽  
R Lurz ◽  
T Börner
Keyword(s):  
Mitochondrial Dna ◽  
Higher Plants ◽  
Chenopodium Album ◽  
Rolling Circle Replication ◽  
Higher Plant ◽  
Electron Microscopic ◽  
Rolling Circle ◽  
Microscopic Studies ◽  
Whole Plants

The mitochondrial genomes of higher plants are larger and more complex than those of all other groups of organisms. We have studied the in vivo replication of chromosomal and plasmid mitochondrial DNAs prepared from a suspension culture and whole plants of the dicotyledonous higher plant Chenopodium album (L.). Electron microscopic studies revealed sigma-shaped, linear, and open circular molecules (subgenomic circles) of variable size as well as a minicircular plasmid of 1.3 kb (mp1). The distribution of single-stranded mitochondrial DNA in the sigma structures and the detection of entirely single-stranded molecules indicate a rolling-circle type of replication of plasmid mp1 and subgenomic circles. About half of the sigma-like molecules had tails exceeding the lengths of the corresponding circle, suggesting the formation of concatemers. Two replication origins (nicking sites) could be identified on mpl by electron microscopy and by a new approach based on the mapping of restriction fragments representing the identical 5' ends of the tails of sigma-like molecules. These data provide, for the first time, evidence for a rolling-circle mode of replication in the mitochondria of higher plants.

scholarly journals Cellulose biosynthesis in higher plants

2014 ◽  
Vol 65 (1-2) ◽  
pp. 17-24 ◽  
Author(s):  
Krystyna Kudlicka ◽  
R. M. Brown, Jr
Keyword(s):  
Higher Plants ◽  
Regulatory Protein ◽  
Cellulose Synthase ◽  
Cell Disruption ◽  
Cellulose Synthesis ◽  
Higher Plant ◽  
Cellulose Synthase Complex ◽  
Enzyme Complexes

Knowledge of the control and regulation of cellulose synthesis is fundamental to an understanding of plant development since cellulose is the primary structural component of plant cell walls. <em>In vivo</em>, the polymerization step requires a coordinated transport of substrates across membranes and relies on delicate orientations of the membrane-associated synthase complexes. Little is known about the properties of the enzyme complexes, and many questions about the biosynthesis of cell wall components at the cell surface still remain unanswered. Attempts to purify cellulose synthase from higher plants have not been successful because of the liability of enzymes upon isolation and lack of reliable <em>in vitro</em> assays. Membrane preparations from higher plant cells incorporate UDP-glucose into a glucan polymer, but this invariably turns out to be predominantly β -1,3-linked rather than β -1,4-linked glucans. Various hypotheses have been advanced to explain this phenomenon. One idea is that callose and cellulose-synthase systems are the same, but cell disruption activates callose synthesis preferentially. A second concept suggests that a regulatory protein as a part of the cellulose-synthase complex is rapidly degraded upon cell disruption. With new methods of enzyme isolation and analysis of the <em>in vitro</em> product, recent advances have been made in the isolation of an active synthase from the plasma membrane whereby cellulose synthase was separated from callose synthase.

A New Working Hypothesis for the Structure and Function of the Golgi Apparatus in Plant Cell Wall Biogenesis

1973 ◽  
Vol 31 ◽  
pp. 456-457 ◽  
Author(s):  
R. Malcolm Brown
Keyword(s):  
Golgi Apparatus ◽  
Plant Cell Wall ◽  
Higher Plants ◽  
Synthetase Activity ◽  
Higher Plant ◽  
General Belief ◽  
Glucan Synthetase ◽  
And Function

It is the general belief of many investigators that the pathway of cellulose biogenesis occurs via soluble pools of hexose phosphate monomers and the plasma membrane which is thought to be the site of polymerization and/or crystalization. Brown and coworkers and Ray (see 1) have proposed to the contrary that the Golgi apparatus is the site of cellulose biogenesis in certain scale-producing algae and higher plants respectively. While it has been fairly well established that cellulose can be biosynthesized by the Golgi apparatus, considerable doubt has been expressed that this type of system could be applicable to cellulose biogenesis in higher plant systems. Conversely, the problems associated with in vitro cellulose biosynthesis in Golgi-enriched homogenates raises questions about the in vivo localization of B-(1,4)-glucan synthetase activity.

scholarly journals Cadmium against Higher Plant Photosynthesis -a Variety of Effects and Where Do They Possibly Come From?

1999 ◽  
Vol 54 (9-10) ◽  
pp. 723-729 ◽  
Author(s):  
Zbigniew Krupa
Keyword(s):  
Carbon Metabolism ◽  
Metabolic Pathways ◽  
Higher Plants ◽  
Photosynthetic Apparatus ◽  
Structure And Function ◽  
Metabolic Processes ◽  
Higher Plant ◽  
Plant Photosynthesis ◽  
And Function

The complexity of in vivo toxic effects of Cd on higher plants makes almost impossible an accurate distinction between direct and indirect mechanisms of its action on the photosynthetic apparatus. We, therefore, postulate that multiple Cd effects on plant physiological and metabolic processes may finally be focused on photosynthesis. This would also explain the phenomenon that only a small fraction of Cd entering chloroplasts may cause such disastrous changes in their structure and function. In return, the inhibition of photosynthesis affects numerous metabolic pathways dependent on the primary carbon metabolism

The Molecular Weight of rRNA Precursor Molecules and Their Processing in Higher Plant Cells

1979 ◽  
Vol 34 (3-4) ◽  
pp. 253-258 ◽  
Author(s):  
Ursula Seitz ◽  
Ulrich Seitz
Keyword(s):  
Molecular Weight ◽  
Higher Plants ◽  
Petroselinum Crispum ◽  
Acer Pseudoplatanus ◽  
Polyacrylamide Gels ◽  
Higher Plant ◽  
Molecular Weights ◽  
Precursor Molecules ◽  
Primary Gene

Abstract Actively dividing callus cells of higher plants (Petroselinum crispum, Daucus carota, Acer pseudoplatanus) were used to detect the primary gene product of rDNA in vivo. Parsley and carrot cells were labelled with [32P] orthophosphate. Under non-denaturing conditions, in both cases only one high molecular weight rRNA precursor was present on polyacrylamide gels. Its molecular weight did not exceed 2.5 × 106 dalton. Under denaturing conditions, 2.0 - 2.1 × 106 dalton were determined on formamide gels. This rRNA precursor was already present after a labelling period of 5 -10 min. In parsley cells labelled mature rRNA (25S and 18S) arrived in the cytoplasm 45 min after onset of incubation.In Acer pseudoplatanus incubated with [3H] uridine two rapidly labelled components did emerge from polyacrylamide gels without formamide; their molecular weights were 2.3 and 3.2 - 3.4 × 106 dalton. After electrophoresis in formamide, the larger component disappeared, thus indicating that it would be an intermolecular aggregate of different for the existence of rRNA precursors exceeding the molecular weight of 2.5 × 106 dalton.

scholarly journals The dynamic nature of plant mitochondrial genome organization.

1997 ◽  
Vol 44 (2) ◽  
pp. 239-250 ◽  
Author(s):  
H Jańska ◽  
M Wołoszyńska
Keyword(s):  
Evolutionary Dynamics ◽  
Size Structure ◽  
Higher Plants ◽  
Mitochondrial Genomes ◽  
Higher Plant ◽  
Plant Mitochondrial Genome ◽  
Plant Mtdna ◽  
Characteristic Features ◽  
Eukaryotic Organisms

The characteristic features of higher plant mitochondrial genomes: size, structure, recombination activity and evolutionary dynamics, are reviewed with the emphasis on the mitochondrial DNA (mtDNA) of Phaseolus vulgaris. Among all examined eukaryotic organisms, higher plants were found to contain the largest and most complex mitochondrial genomes. The plant mtDNA structure in vivo and mechanisms of evolution are controversial. We present the currently accepted models and how these models correspond to mitochondrial genomes of several common bean lines.

scholarly journals Reorganization of microtubules in endosperm cells and cell fragments of the higher plant Haemanthus in vivo.

1986 ◽  
Vol 102 (1) ◽  
pp. 263-281 ◽  
Author(s):  
A S Bajer ◽  
J Molè-Bajer
Keyword(s):  
Mitotic Spindle ◽  
Polar Region ◽  
Higher Plants ◽  
Higher Plant ◽  
Initial Size ◽  
Plant Microtubules ◽  
Cell Fragments ◽  
Microtubular Structures ◽  
Prevailing View

The reorganization of the microtubular meshwork was studied in intact Haemanthus endosperm cells and cell fragments (cytoplasts). This higher plant tissue is devoid of a known microtubule organizating organelle. Observations on living cells were correlated with microtubule arrangements visualized with the immunogold method. In small fragments, reorganization did not proceed. In medium and large sized fragments, microtubular converging centers formed first. Then these converging centers reorganized into either closed bushy microtubular spiral or chromosome-free cytoplasmic spindles/phragmoplasts. Therefore, the final shape of organized microtubular structures, including spindle shaped, was determined by the initial size of the cell fragments and could be achieved without chromosomes or centrioles. Converging centers elongate due to the formation of additional structures resembling microtubular fir trees. These structures were observed at the pole of the microtubular converging center in anucleate fragments, accessory phragmoplasts in nucleated cells, and in the polar region of the mitotic spindle during anaphase. Therefore, during anaphase pronounced assembly of new microtubules occurs at the polar region of acentriolar spindles. Moreover, statistical analysis demonstrated that during the first two-thirds of anaphase, when chromosomes move with an approximately constant speed, kinetochore fibers shorten, while the length of the kinetochore fiber complex remains constant due to the simultaneous elongation of their integral parts (microtubular fir trees). The half-spindle shortens only during the last one-third of anaphase. These data contradict the presently prevailing view that chromosome-to-pole movements in acentriolar spindles of higher plants are concurrent with the shortening of the half-spindle, the self-reorganizing property of higher plant microtubules (tubulin) in vivo. It may be specific for cells without centrosomes and may be superimposed also on other microtubule-related processes.

In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.

1978 ◽  
Vol 36 (2) ◽  
pp. 434-435
Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland
Keyword(s):  
Cell Wall ◽  
Self Assembly ◽  
Plant Cell Wall ◽  
Higher Plants ◽  
Three Dimensional ◽  
Cytochemical Study ◽  
Wall Components

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.

Traceable Peptidic Ligands that Target Ghrelin Receptors

2020 ◽  
Vol 21 (10) ◽  
pp. 955-964 ◽  
Author(s):  
Mengjie Liu ◽  
John Wade ◽  
Mohammed Akhter Hossain
Keyword(s):  
In Vivo Imaging ◽  
Peptide Hormone ◽  
Structural Features ◽  
Pharmacological Properties ◽  
Imaging Studies ◽  
Cognate Receptor ◽  
Ghrelin Receptors ◽  
Biochemical Research

: Ghrelin is a 28-amino acid octanoylated peptide hormone that is implicated in many physiological and pathophysiological processes. Specific visualization of ghrelin and its cognate receptor using traceable ligands is crucial in elucidating the localization, functions, and expression pattern of the peptide’s signaling pathway. Here 12 representative radio- and fluorescently-labeled peptide-based ligands are reviewed for in vitro and in vivo imaging studies. In particular, the focus is on their structural features, pharmacological properties, and applications in further biochemical research.

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