oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
In silico Study on Sulfated and Non-Sulfated Carbohydrate Chains from Proteoglycans in Cnidaria and Interaction with Collagen  [PDF]
Thomas Eckert, Sabine St?tzel, Monika Burg-Roderfeld, Judith Sewing, Thomas Lütteke, Nikolay E. Nifantiev, Johannes F. G. Vliegenthart, Hans-Christian Siebert
Open Journal of Physical Chemistry (OJPC) , 2012, DOI: 10.4236/ojpc.2012.22017
Abstract: Proteoglycans and collagen molecules are interacting with each other thereby forming various connective tissues. The sulfation pattern of proteoglycans differs depending on the kind of tissue and/or the degree of maturation. Tissues from Cnidaria are suitable examples for exploration of the effects in relation to the presence and the absence of sulfate groups, when studying characteristic fragments of the long proteoglycan carbohydrate chains in silico. It has been described that a non-sulfated chondroitin appears as a scaffold in early morphogenesis of all nematocyst types in Hydra. On the other hand, sulfated glucosaminoglycans play an important role in various developmental processes of Cnidaria. In order to understand this biological phenomenon on a sub-molecular level we have analysed the structures of sulfated and non-sulfated proteoglycan carbohydrate chains as well as the structure of diverse collagen molecules with computational methods including quantum chemical calculations. The strong interactions between the sulfate groups of the carbohydrates moieties in proteoglycans and positively charged regions of collagen are essential in stabilizing various Cnidaria tissues but could hinder the nematocyst formation and its proper function. The results of our quantum chemical calculations show that the sulfation pattern has a significant effect on the conformation of chondroitin structures under study.
Identification and Characterization of Sulfated Carbohydrate-Binding Protein from Lactobacillus reuteri  [PDF]
Keita Nishiyama, Ayaka Ochiai, Daigo Tsubokawa, Kazuhiko Ishihara, Yuji Yamamoto, Takao Mukai
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0083703
Abstract: We previously purified a putative sulfated-galactosylceramide (sulfatide)-binding protein with a molecular weight of 47 kDa from the cell surface of Lactobacillus reuteri JCM1081. The aim of this study was to identify the 47-kDa protein, examine its binding to sulfated glycolipids and mucins, and evaluate its role in bacterial adhesion to mucosal surfaces. By cloning and sequencing analysis, the 47-kDa protein was identified as elongation factor-Tu (EF-Tu). Adhesion properties were examined using 6×Histidine-fused EF-Tu (His6-EF-Tu). Surface plasmon resonance analysis demonstrated pH-dependent binding of His6-EF-Tu to sulfated glycolipids, but not to neutral or sialylated glycolipids, suggesting that a sulfated galactose residue was responsible for EF-Tu binding. Furthermore, His6-EF-Tu was found to bind to porcine gastric mucin (PGM) by enzyme-linked immunosorbent assay. Binding was markedly reduced by sulfatase treatment of PGM and in the presence of acidic and desialylated oligosaccharide fractions containing sulfated carbohydrate residues prepared from PGM, demonstrating that sulfated carbohydrate moieties mediated binding. Histochemical staining revealed similar localization of His6-EF-Tu and high iron diamine staining in porcine mucosa. These results indicated that EF-Tu bound PGM via sulfated carbohydrate moieties. To characterize the contribution of EF-Tu to the interaction between bacterial cells and PGM, we tested whether anti-EF-Tu antibodies could inhibit the interaction. Binding of L. reuteri JCM1081 to PGM was significantly blocked in a concentration-dependent matter, demonstrating the involvement of EF-Tu in bacterial adhesion. In conclusion, the present results demonstrated, for the first time, that EF-Tu bound sulfated carbohydrate moieties of sulfated glycolipids and sulfomucin, thereby promoting adhesion of L. reuteri to mucosal surfaces.
Sulfated proteoglycans as modulators of neuronal migration and axonal decussation in the developing midbrain
Cavalcante, L.A.;Garcia-Abreu, J.;Mendes, F.A.;Moura Neto, V.;Silva, L.C.F.;Onofre, G.;Weissmüller, G.;Carvalho, S.L.;
Brazilian Journal of Medical and Biological Research , 2003, DOI: 10.1590/S0100-879X2003000800005
Abstract: proteoglycans are abundant in the developing brain and there is much circumstantial evidence for their roles in directional neuronal movements such as cell body migration and axonal growth. we have developed an in vitro model of astrocyte cultures of the lateral and medial sectors of the embryonic mouse midbrain, that differ in their ability to support neuritic growth of young midbrain neurons, and we have searched for the role of interactive proteins and proteoglycans in this model. neurite production in co-cultures reveals that, irrespective of the previous location of neurons in the midbrain, medial astrocytes exert an inhibitory or nonpermissive effect on neuritic growth that is correlated to a higher content of both heparan and chondroitin sulfates (hs and cs). treatment of astrocytes with chondroitinase abc revealed a growth-promoting effect of cs on lateral glia but treatment with exogenous cs-4 indicated a u-shaped dose-response curve for cs. in contrast, the growth-inhibitory action of medial astrocytes was reversed by exogenous cs-4. treatment of astrocytes with heparitinase indicated that the growth-inhibitory action of medial astrocytes may depend heavily on hs by an as yet unknown mechanism. the results are discussed in terms of available knowledge on the binding of hs proteoglycans to interactive proteins, with emphasis on the importance of unraveling the physiological functions of glial glycoconjugates for a better understanding of neuron-glial interactions.
Sulfated proteoglycans as modulators of neuronal migration and axonal decussation in the developing midbrain  [cached]
Cavalcante L.A.,Garcia-Abreu J.,Mendes F.A.,Moura Neto V.
Brazilian Journal of Medical and Biological Research , 2003,
Abstract: Proteoglycans are abundant in the developing brain and there is much circumstantial evidence for their roles in directional neuronal movements such as cell body migration and axonal growth. We have developed an in vitro model of astrocyte cultures of the lateral and medial sectors of the embryonic mouse midbrain, that differ in their ability to support neuritic growth of young midbrain neurons, and we have searched for the role of interactive proteins and proteoglycans in this model. Neurite production in co-cultures reveals that, irrespective of the previous location of neurons in the midbrain, medial astrocytes exert an inhibitory or nonpermissive effect on neuritic growth that is correlated to a higher content of both heparan and chondroitin sulfates (HS and CS). Treatment of astrocytes with chondroitinase ABC revealed a growth-promoting effect of CS on lateral glia but treatment with exogenous CS-4 indicated a U-shaped dose-response curve for CS. In contrast, the growth-inhibitory action of medial astrocytes was reversed by exogenous CS-4. Treatment of astrocytes with heparitinase indicated that the growth-inhibitory action of medial astrocytes may depend heavily on HS by an as yet unknown mechanism. The results are discussed in terms of available knowledge on the binding of HS proteoglycans to interactive proteins, with emphasis on the importance of unraveling the physiological functions of glial glycoconjugates for a better understanding of neuron-glial interactions.
Hydrophilic Aromatic Residue and in silico Structure for Carbohydrate Binding Module  [PDF]
Wei-Yao Chou, Tun-Wen Pai, Ting-Ying Jiang, Wei-I Chou, Chuan-Yi Tang, Margaret Dah-Tsyr Chang
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0024814
Abstract: Carbohydrate binding modules (CBMs) are found in polysaccharide-targeting enzymes and increase catalytic efficiency. Because only a relatively small number of CBM structures have been solved, computational modeling represents an alternative approach in conjunction with experimental assessment of CBM functionality and ligand-binding properties. An accurate target-template sequence alignment is the crucial step during homology modeling. However, low sequence identities between target/template sequences can be a major bottleneck. We therefore incorporated the predicted hydrophilic aromatic residues (HARs) and secondary structure elements into our feature-incorporated alignment (FIA) algorithm to increase CBM alignment accuracy. An alignment performance comparison for FIA and six others was made, and the greatest average sequence identities and similarities were achieved by FIA. In addition, structure models were built for 817 representative CBMs. Our models possessed the smallest average surface-potential z scores. Besides, a large true positive value for liagnd-binding aromatic residue prediction was obtained by HAR identification. Finally, the pre-simulated CBM structures have been deposited in the Database of Simulated CBM structures (DS-CBMs). The web service is publicly available at http://dscbm.life.nthu.edu.tw/ and http://dscbm.cs.ntou.edu.tw/.
Decorin is one of the proteoglycans expressed in Walker 256 rat mammary carcinoma
Oba-Shinjo, S.M.;Berto, A.G.A.;Passerotti, C.C.;Barbosa, C.D.;Sampaio, L.O.;
Brazilian Journal of Medical and Biological Research , 2003, DOI: 10.1590/S0100-879X2003000800015
Abstract: proteoglycan and glycosaminoglycan content was analyzed in a model of rat mammary carcinoma to study the roles of these compounds in tumorigenesis. hyaluronic acid and proteoglycans bearing chondroitin and/or dermatan sulfate chains were detected in solid tumors obtained after subcutaneous inoculation of walker 256 rat carcinoma cells. about 10% of sulfated glycosaminoglycan chains corresponded to heparan sulfate. the small leucine-rich proteoglycan, decorin, was identified as one of the proteoglycans, in addition to others of higher molecular weight, by cross-reaction with an antiserum raised against pig laryngeal decorin and by n-terminal amino acid sequencing. decorin was separated from other proteoglycans by hydrophobic chromatography and its complete structure was determined. it has a molecular weight of about 85 kda and a dermatan chain of 45 kda with 4-sulfated disaccharides. after degradation of the glycosaminoglycan chain, three core proteins of different molecular weight (36, 46 and 56 kda) were identified. the presence of hyaluronic acid and decorin has been reported in a variety of tumors and tumor cells. in the walker 256 mammary carcinoma model, hyaluronic acid may play an important role in tumor progression, since it provides a more hydrated extracellular matrix. on the other hand, decorin, which is expressed by stromal cells, represents a host defense response to tumor growth.
Decorin is one of the proteoglycans expressed in Walker 256 rat mammary carcinoma  [cached]
Oba-Shinjo S.M.,Berto A.G.A.,Passerotti C.C.,Barbosa C.D.
Brazilian Journal of Medical and Biological Research , 2003,
Abstract: Proteoglycan and glycosaminoglycan content was analyzed in a model of rat mammary carcinoma to study the roles of these compounds in tumorigenesis. Hyaluronic acid and proteoglycans bearing chondroitin and/or dermatan sulfate chains were detected in solid tumors obtained after subcutaneous inoculation of Walker 256 rat carcinoma cells. About 10% of sulfated glycosaminoglycan chains corresponded to heparan sulfate. The small leucine-rich proteoglycan, decorin, was identified as one of the proteoglycans, in addition to others of higher molecular weight, by cross-reaction with an antiserum raised against pig laryngeal decorin and by N-terminal amino acid sequencing. Decorin was separated from other proteoglycans by hydrophobic chromatography and its complete structure was determined. It has a molecular weight of about 85 kDa and a dermatan chain of 45 kDa with 4-sulfated disaccharides. After degradation of the glycosaminoglycan chain, three core proteins of different molecular weight (36, 46 and 56 kDa) were identified. The presence of hyaluronic acid and decorin has been reported in a variety of tumors and tumor cells. In the Walker 256 mammary carcinoma model, hyaluronic acid may play an important role in tumor progression, since it provides a more hydrated extracellular matrix. On the other hand, decorin, which is expressed by stromal cells, represents a host defense response to tumor growth.
The structure and function of cartilage proteoglycans  [PDF]
P J Roughley
European Cells and Materials (ECM) , 2006,
Abstract: Cartilage contains a variety of proteoglycans that are essential for its normal function. These include aggrecan, decorin, biglycan, fibromodulin and lumican. Each proteoglycan serves several functions that are determined by both its core protein and its glycosaminoglycan chains. This review discusses the structure/function relationships of the cartilage proteoglycans, and the manner in which perturbations in proteoglycan structure or abundance can adversely affect tissue function.
Collagens and proteoglycans of the corneal extracellular matrix
Michelacci, Y.M.;
Brazilian Journal of Medical and Biological Research , 2003, DOI: 10.1590/S0100-879X2003000800009
Abstract: the cornea is a curved and transparent structure that provides the initial focusing of a light image into the eye. it consists of a central stroma that constitutes 90% of the corneal depth, covered anteriorly with epithelium and posteriorly with endothelium. its transparency is the result of the regular spacing of collagen fibers with remarkably uniform diameter and interfibrillar space. corneal collagen is composed of heterotypic fibrils consisting of type i and type v collagen molecules. the cornea also contains unusually high amounts of type vi collagen, which form microfibrillar structures, facit collagens (xii and xiv), and other nonfibrillar collagens (xiii and xviii). facit collagens and other molecules, such as leucine-rich repeat proteoglycans, play important roles in modifying the structure and function of collagen fibrils. proteoglycans are macromolecules composed of a protein core with covalently linked glycosaminoglycan side chains. four leucine-rich repeat proteoglycans are present in the extracellular matrix of corneal stroma: decorin, lumican, mimecan and keratocan. the first is a dermatan sulfate proteoglycan, and the other three are keratan sulfate proteoglycans. experimental evidence indicates that the keratan sulfate proteoglycans are involved in the regulation of collagen fibril diameter, and dermatan sulfate proteoglycan participates in the control of interfibrillar spacing and in the lamellar adhesion properties of corneal collagens. heparan sulfate proteoglycans are minor components of the cornea, and are synthesized mainly by epithelial cells. the effect of injuries on proteoglycan synthesis is discussed.
Proteoglycans production by aortic vascular smooth muscle cells from hypertensive rats
Risler,Norma; Castro,Claudia; Cruzado,Montserrat; González,Susana; Miatello,Roberto;
Biocell , 2003,
Abstract: remodeling of large and small arteries contributes to the development and complications of hypertension. artery structural changes in chronic sustained hypertension include vascular smooth muscle cells (vsmc) proliferation and extracellular matrix (ecm) modifications. extracellular constituents such as proteoglycans (pgs), may modulate vascular stiffness and vsmc growth and differentiation. we examined the effect of growth factors on secreted and membrane-bound pgs synthesis by cultured aortic smooth muscle cells (smc) from 12- to 14- week-old spontaneously hypertensive rats (shr) and age-matched wistar rats. after stimulation with platelet-derived growth factor (pdgf-bb), 10% fetal calf serum (fcs) or 0.1% fcs as control, pgs synthesis (dpm/ng dna) was evaluated in the medium (m-ecm) and in the cell layer (p-ecm) by a double-isotopic label method using both [3h]-glucosamine and [35s]-sodium sulfate which are incorporated into all complex carbohydrates or only into sulfated dysaccharides, respectively. data are presented as percent of the control (0.1% fcs). shr vsmc displayed a significantly greater synthesis of m-ecm [3h]-pgs than wistar rat cells, with both treatments, but no differences in m-ecm [35s] uptake were found in any case. in the p-ecm, both pdgf-bb and 10% fcs produced a greater effect on [3h]-pgs and sulfated pgs synthesis in vsmc from shr. an important change seen in shr cells was a significant decreased sulfation, assesed by [35s]/[ 3h] ratio, in basal and stimulation conditions. present results indicate the existence of changes in pgs synthesis and modulation in vsmc from a conduit-artery of shr and support the pathophysiological role proposed for matrix proteoglycans in the vascular wall changes associated to hypertension and related vascular diseases as atherosclerosis.
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.