scholarly journals Biochemical and Initial Structural Characterization of the Monocot Chimeric Jacalin OsJAC1

2021 ◽  
Vol 22 (11) ◽  
pp. 5639
Author(s):  
Nikolai Huwa ◽  
Oliver H. Weiergräber ◽  
Christian Kirsch ◽  
Ulrich Schaffrath ◽  
Thomas Classen

The monocot chimeric jacalin OsJAC1 from Oryza sativa consists of a dirigent and a jacalin-related lectin domain. The corresponding gene is expressed in response to different abiotic and biotic stimuli. However, there is a lack of knowledge about the basic function of the individual domains and their contribution to the physiological role of the entire protein. In this study, we have established a heterologous expression in Escherichia coli with high yields for the full-length protein OsJAC1 as well as its individual domains. Our findings showed that the secondary structure of both domains is dominated by β-strand elements. Under reducing conditions, the native protein displayed clearly visible transition points of thermal unfolding at 59 and 85 °C, which could be attributed to the lectin and the dirigent domain, respectively. Our study identified a single carbohydrate-binding site for each domain with different specificities towards mannose and glucose (jacalin domain), and galactose moieties (dirigent domain), respectively. The recognition of different carbohydrates might explain the ability of OsJAC1 to respond to different abiotic and biotic factors. This is the first report of specific carbohydrate-binding activity of a DIR domain, shedding new light on its function in the context of this monocot chimeric jacalin.

1996 ◽  
Vol 16 (4) ◽  
pp. 1436-1449 ◽  
Author(s):  
K Moberg ◽  
M A Starz ◽  
J A Lees

The E2F transcription factor couples the coordinate expression of cell cycle proteins to their appropriate transition points. Its activity is controlled by the cell cycle regulators pRB, p107, and p130. These bind to E2F at defined but distinct stages of the cell cycle. Using specific antisera, we have identified the DP and E2F components of each of these species. Although present at very different levels, DP-1 and DP-2 are evenly distributed among each of these complexes. In contrast, the individual E2Fs have distinctly different binding profiles. Consistent with previous studies, E2F-1, E2F-2, and E2F-3 bind specifically to the retinoblastoma protein. In each case, their expression and DNA binding activity are restricted to post-G1/S fractions. Surprisingly, E2F-1 and E2F-3 make unequal contributions to the pRB-associated and free E2F activity, suggesting that these proteins perform different cell cycle functions. Most significantly, this study showed E2F-4 accounts for the vast majority of the endogenous E2F activity. In arrested cells, E2F-4 is sequestered by the p130 protein. However, as the cells pass the G1-to-S transition, the levels of pRB and p107 increase and E2F-4 now associates with both of these regulators. Despite this, a considerable amount of E2F-4 exists as free E2F. In G1 cells, this accounts for almost all of the free activity. Once the cells enter S phase, free E2F is composed of an equal mixture of E2F-4 and E2F-1.


Marine Drugs ◽  
2018 ◽  
Vol 16 (12) ◽  
pp. 471 ◽  
Author(s):  
Svetlana Kovalchuk ◽  
Nina Buinovskaya ◽  
Galina Likhatskaya ◽  
Valery Rasskazov ◽  
Oksana Son ◽  
...  

The GalNAc/Gal-specific lectin from the sea mussel Crenomytilus grayanus (CGL) with anticancer activity represents а novel lectin family with β-trefoil fold. Earlier, the crystal structures of CGL complexes with globotriose, galactose and galactosamine, and mutagenesis studies have revealed that the lectin contained three carbohydrate-binding sites. The ability of CGL to recognize globotriose (Gb3) on the surface of breast cancer cells and bind mucin-type glycoproteins, which are often associated with oncogenic transformation, makes this compound to be perspective as a biosensor for cancer diagnostics. In this study, we describe results on in silico analysis of binding mechanisms of CGL to ligands (galactose, globotriose and mucin) and evaluate the individual contribution of the amino acid residues from carbohydrate-binding sites to CGL activity by site-directed mutagenesis. The alanine substitutions of His37, His129, Glu75, Asp127, His85, Asn27 and Asn119 affect the CGL mucin-binding activity, indicating their importance in the manifestation of lectin activity. It has been found that CGL affinity to ligands depends on their structure, which is determined by the number of hydrogen bonds in the CGL-ligand complexes. The obtained results should be helpful for understanding molecular machinery of CGL functioning and designing a synthetic analog of CGL with enhanced carbohydrate-binding properties.


2002 ◽  
Vol 69 ◽  
pp. 59-72 ◽  
Author(s):  
Kurt Drickamer ◽  
Andrew J. Fadden

Many biological effects of complex carbohydrates are mediated by lectins that contain discrete carbohydrate-recognition domains. At least seven structurally distinct families of carbohydrate-recognition domains are found in lectins that are involved in intracellular trafficking, cell adhesion, cell–cell signalling, glycoprotein turnover and innate immunity. Genome-wide analysis of potential carbohydrate-binding domains is now possible. Two classes of intracellular lectins involved in glycoprotein trafficking are present in yeast, model invertebrates and vertebrates, and two other classes are present in vertebrates only. At the cell surface, calcium-dependent (C-type) lectins and galectins are found in model invertebrates and vertebrates, but not in yeast; immunoglobulin superfamily (I-type) lectins are only found in vertebrates. The evolutionary appearance of different classes of sugar-binding protein modules parallels a development towards more complex oligosaccharides that provide increased opportunities for specific recognition phenomena. An overall picture of the lectins present in humans can now be proposed. Based on our knowledge of the structures of several of the C-type carbohydrate-recognition domains, it is possible to suggest ligand-binding activity that may be associated with novel C-type lectin-like domains identified in a systematic screen of the human genome. Further analysis of the sequences of proteins containing these domains can be used as a basis for proposing potential biological functions.


PEDIATRICS ◽  
1988 ◽  
Vol 81 (2) ◽  
pp. 291-295
Author(s):  
Robert H. Yolken ◽  
Flora Leister ◽  
Siok-Bi Wee ◽  
Robin Miskuff ◽  
Steven Vonderfecht

The prevalence of antibodies to human rotaviruses in commercially available eggs and egg products that are suitable for human consumption was investigated. The yolks of virtually all of the individual eggs and pasteurized pooled egg preparations contain antirotavirus antibodies detectable by means of enzyme immunoassay systems. Also, the eggs and egg preparations are capable of inhibiting the growth of two strains of rotaviruses in tissue culture. Chromatographic studies indicated that the antigen-binding activity is limited largely to the immunoglobulin fractions of the egg yolks. The antibody levels in eggs can be increased by the immunization of hens with purified rotavirus preparations, and the immunoglobulins isolated from the eggs of immunized hens can prevent the development of rotavirus gastroenteritis in experimentally infected animals. Egg preparations might serve as a practical source of antiviral antibodies suitable for consumption by infants and young children.


2011 ◽  
Vol 1 (2) ◽  
pp. 35-44
Author(s):  
Hanne Nørreklit

The purpose of this article is to establish the symbolic forms that are presently used in selected mainstream management models and to assess whether the connection between leadership and individual human reality would be improved if the management models were fundamentally inspired by those used by a successful manager and artist.The theoretical starting point of this article is Cassirer’s (Cassirer 1999) philosophy of symbolic forms. A symbolic form is “a way of having a life world” (own translation) (Cassirer 1999). In a symbolic form, a person discovers and unfolds an ability to build his own universe as an ideal universe which enables the person to “understand and interpret, to articulate and organize, synthesize and universalize his human experience” (Cassirer 1962: 221). Symbolic forms such as art, science, myth and religion thus have common features and structures in their basic function of creating common human existence. When the symbolic form is science, ideals of objectivity and precision in the description of phenomena and their relations dominate man’s formation of his universe. In art, man unfolds an ability to be subjective and create empathetic insight into matters and their diversity (Cassirer 1962). Where science as symbolic form conceptualizes objects, art teaches us empathetic insight. The symbolic forms of art and science perceive a phenomenon differently. For example, science will perhaps see a constellation as a trigonometric function, whereas it may be considered by art as a “Hogarthian shape of beauty” (own translation) (Cassirer 1999: 62). Like the symbolic form of art, the symbolic form of myth builds on emotional sympathy, but differs by believing in the existence of the constellation. It is used to create a natural or magical unity of life. Monotheistic religions also include ideas of striving for a sense of unity, but here the idea is to achieve a universal, ethical sense of unity in an individualized society. Thus the symbolic form of religion helps the individual to choose between right and wrong.With this in mind, we examine the use of symbolic forms embedded in selected mainstream management models. Subsequently, we study the symbolic forms embedded in the management discourse as the concept is unfolded by the successful Artistic Director of the Royal Danish Opera, Kasper Holten, when he talks about management, with a view to determining the extent to which this practice differs from the symbolic forms embedded in the mainstream management models. The analysis shows that mainstream management models are primarily rooted in the symbolic form of science, although they tend to gradually include the symbolic form of religion or the symbolic form of myth. Generally speaking, the mainstream management models tend to exercise power over the individual’s emphatic insight and autonomous reflection and thereby constrain the scope for human creativity and individuality. Distinctively, Kasper Holten’s management discourse integrates the symbolic forms of art and science. With art as the dominant symbolic form, Kasper rejects new public management’s perception about opera and the management of art while at the same time – through discourses that bind to the individuality of the network of players – forming personal and social identities which come together to realize a world of existential ideas about operas in general as well as opera in particular.The article is relevant because it provides insight into the ways in which management models, through the use of myth and science as symbolic forms, exercise influence on human existence and interaction and thereby influence the scope for human freedom and exercise of power and also because it provides insight into the features and structures concerning human existence and co-existence from which mainstream management models cut themselves off by not using art as a form of consciousness. The constructive aspect is a parallel outline of features and structures in a new management discourse which are better suited for postmodern society.


Lampas ◽  
2020 ◽  
Vol 53 (2) ◽  
pp. 259-270
Author(s):  
Jasper de Bruin

Summary The subject of this article is the interaction between the military and civilian communities in the Dutch Limes zone. Central questions are what influence the Roman army had on the civilian population, how the contacts between both groups were shaped, and how the individual soldiers interacted with civilians. The influence of the army was most prominent at the forts, but was also present outside the areas where the military was stationed. Civilians enlisted in the army, creating intermediaries. The Roman cities also functioned as transition points between the army and the civilian population, but they may have had other, more primary military functions as well. Contacts between the two groups were generally peaceful and provided benefits for both. As military and civilian communities became increasingly intertwined, it is likely that individual contacts between the two also contributed to this process.


1987 ◽  
Vol 247 (3) ◽  
pp. 679-685 ◽  
Author(s):  
F Watanabe ◽  
Y Nakano ◽  
S Kitaoka

In Euglena gracilis SM-ZK, a bleached mutant of E. gracilis z, the cobalamin- (Cbl-)binding activity was distributed in cytosol (49.2%), mitochondria (20.3%) and microsomal fraction (20.4%). The cytosolic Cbl-binding activity gave two major peaks in isoelectric focusing. The Cbl-binding protein with pI 3.2 was purified 6500-fold in a yield of 19.9%, and that with pI 4.7 5800-fold in a yield of 11.9%. The monomeric Mr values of both Cbl-binding proteins were about 66,000. The Cbl-binding activity of both proteins showed a very low pH-dependency, and thiol groups and metal ions were not concerned with the Cbl-binding activities. The Ks values of the Cbl-binding proteins with pI 3.8 and 4.7 for CN-Cbl were 1.0 and 2.0 nM respectively. The Cbl-binding protein with pI 3.8 was shown to be immunologically identical with the protein with pI 4.7 by double-immunodiffusion experiments against antibody to the protein with pI 3.8. The two cytosolic Cbl-binding proteins did not show the activities of Cbl-dependent enzymes in E. gracilis, N5-methyltetrahydrofolate:homocysteine methyltransferase, methylmalonyl-CoA mutase and ribonucleotide reductase, suggesting that the two cytosolic Cbl-binding proteins play a physiological role as intracellular Cbl carriers.


2018 ◽  
Vol 74 (5) ◽  
pp. 463-470 ◽  
Author(s):  
Christian Roth ◽  
Olga V. Moroz ◽  
Antonio Ariza ◽  
Lars K. Skov ◽  
Keiichi Ayabe ◽  
...  

Glucoamylases are one of the most important classes of enzymes in the industrial degradation of starch biomass. They consist of a catalytic domain and a carbohydrate-binding domain (CBM), with the latter being important for the interaction with the polymeric substrate. Whereas the catalytic mechanisms and structures of the individual domains are well known, the spatial arrangement of the domains with respect to each other and its influence on activity are not fully understood. Here, the structures of three industrially used fungal glucoamylases, two of which are full length, have been crystallized and determined. It is shown for the first time that the relative orientation between the CBM and the catalytic domain is flexible, as they can adopt different orientations independently of ligand binding, suggesting a role as an anchor to increase the contact time and the relative concentration of substrate near the active site. The flexibility in the orientations of the two domains presented a considerable challenge for the crystallization of the enzymes.


1987 ◽  
Vol 252 (3) ◽  
pp. C285-C289 ◽  
Author(s):  
D. B. Zimmer ◽  
L. J. Van Eldik

To understand the physiological role of the calcium-binding proteins S100 alpha and S100 beta, it is necessary to determine the distribution of these proteins and detect their intracellular targets in various tissues. The distribution of immunoreactive S100 alpha and S100 beta in various rat tissues was examined by radioimmunoassay. All tissues examined contained detectable S100, but the S100 beta/S100 alpha ratio in each tissue differed. Brain, adipose, and testes contained 18- to 40-fold more S100 beta than S100 alpha; skin and liver contained approximately equivalent amounts and kidney, spleen, and heart contained 8- to 75-fold more S100 alpha than S100 beta. Analysis of S100-binding proteins by gel overlay showed that each tissue possessed its own complement of binding proteins. The S100 beta-binding profile was indistinguishable from the S100 alpha-binding profile and both of these profiles were distinct from the calmodulin-binding profile. These observations suggest that the differential distribution and quantity of the individual S100 polypeptides and their binding proteins in various tissues may be important factors in determining S100 function.


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