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1.
Eur J Nutr ; 61(8): 4179-4190, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-35864340

RESUMEN

PURPOSE: Agaro-oligosaccharides (AGO), hydrolysis products of agarose, is known to have antioxidant and anti-inflammatory properties. Speculating that AGO is effective for preventing aging, we investigated the longevity-supporting effects of AGO and their mechanisms using Caenorhabditis elegans. METHODS: Caenorhabditis elegans were fed AGO from young adulthood. The lifespan, locomotory activity, lipofuscin accumulation, and heat stress resistance of the worms were examined. To elucidate mechanisms of AGO-mediated longevity, we conducted comprehensive expression analysis using microarrays. Moreover, we used quantitative real-time PCR (qRT-PCR) to verify the genes showing differential expression levels. Furthermore, we measured the lifespan of loss-of-function mutants to determine the genes related to AGO-mediated longevity. RESULTS: AGO extended the lifespan of C. elegans, reduced lipofuscin accumulation, and maintained vigorous locomotion. The microarray analysis revealed that the endoplasmic reticulum-unfolded protein response (ER-UPR) and insulin/insulin-like growth factor-1-mediated signaling (IIS) pathway were activated in AGO-fed worms. The qRT-PCR analysis showed that AGO treatment suppressed sir-2.1 expression, which is a negative regulator of ER-UPR. In loss-of-function mutant of sir-2.1, AGO-induced longevity and heat stress resistance were decreased or cancelled completely. Furthermore, the pro-longevity effect of AGO was decreased in loss-of-function mutants of abnormal Dauer formation (daf) -2 and daf-16, which are IIS pathway-related genes. CONCLUSION: AGO delays the C. elegans aging process and extends their lifespan through the activations of ER-UPR and the IIS pathway.


Asunto(s)
Proteínas de Caenorhabditis elegans , Insulinas , Sirtuinas , Animales , Caenorhabditis elegans/genética , Caenorhabditis elegans/metabolismo , Longevidad/fisiología , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Factor I del Crecimiento Similar a la Insulina/metabolismo , Agar/metabolismo , Agar/farmacología , Antioxidantes/farmacología , Sefarosa/metabolismo , Sefarosa/farmacología , Lipofuscina/metabolismo , Lipofuscina/farmacología , Respuesta de Proteína Desplegada , Oligosacáridos/farmacología , Oligosacáridos/metabolismo , Insulinas/genética , Insulinas/metabolismo , Insulinas/farmacología , Factores de Transcripción Forkhead/genética , Sirtuinas/genética , Sirtuinas/metabolismo
2.
J Phys Ther Sci ; 33(5): 417-422, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-34083881

RESUMEN

[Purpose] Recently, a photo-based smartphone application for angle measurement-"Grid line imaging application Professional"-was developed to evaluate joint disease treatments. The aim of this study was to determine the accuracy and reliability of the application. [Participants and Methods] We measured the knee joint of a mannequin using an application and a universal goniometer. Twelve examiners measured eight knee joints of mannequins at different arbitrary angles using the application and a universal goniometer. Correlations between the application and universal goniometer measurements were examined using scatter plots and correlation coefficients. Systematic errors of the application were visually confirmed using the Bland-Altman method. Intra-class correlation coefficients were used to evaluate the inter-examiner reliability of the application. [Results] The application and universal goniometer measurements showed a good correlation (r=0.99) and no systematic error. The intra-class correlation coefficient for inter-examiner reliability was 0.999. Furthermore, to evaluate intra-examiner reliability, six examiners measured six different knee joints twice using the application on a 2-day interval. The intra-class correlation coefficient for intra-examiner reliability was 0.982. [Conclusion] The accuracy of the application was equivalent to that of a universal goniometer, and both the inter- and intra-examiner reliabilities of the application were almost perfect.

3.
Biosci Biotechnol Biochem ; 82(3): 484-488, 2018 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-29370713

RESUMEN

Papain (cysteine protease), subtilisin (Protin SD-AY10, serine protease), and bacillolysin (Protin SD-NY10, metallo protease) increased the specific volume of gluten-free rice breads by 19-63% compared to untreated bread. In contrast, Newlase F (aspartyl protease) did not expand the volume of the rice bread. In a rheological analysis, the viscoelastic properties of the gluten-free rice batters also depended on the protease categories. Principal component analysis (PCA) analysis suggested that the storage and loss moduli (G' and G″, respectively) at 35 °C, and the maximum values of G' and G″, were important factors in the volume expansion. Judging from the PCA of the viscoelastic parameters of the rice batters, papain and Protin SD-AY10 improved the viscoelasticity for gluten-free rice bread making, and Protin SD-NY effectively expanded the gluten-free rice bread. The rheological properties differed between Protin SD-NY and the other protease treatments.


Asunto(s)
Pan , Dieta Sin Gluten , Elasticidad , Oryza/química , Péptido Hidrolasas/metabolismo , Reología , Temperatura , Viscosidad
4.
Biosci Biotechnol Biochem ; 81(2): 283-291, 2017 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-27832720

RESUMEN

We have recently generated a highly efficient 1,2-α-l-fucosynthase (BbAfcA N423H mutant) by protein engineering of 1,2-α-l-fucosidase from Bifidobacterium bifidum JCM 1254. This synthase could specifically introduce H-antigens (Fucα1-2Gal) into the non-reducing ends of oligosaccharides and in O-linked glycans in mucin glycoprotein. In the present study, we show an extended application of the engineered 1,2-α-l-fucosynthase by demonstrating its ability to insert Fuc residues into N- and O-glycans in fetuin glycoproteins, GM1 ganglioside, and a plant-derived xyloglucan nonasaccharide. This application study broadens the feasibility of this novel H-antigen synthesis technique in functional glycomics.


Asunto(s)
Disacáridos/química , Disacáridos/metabolismo , Fucosa/química , Gangliósidos/química , Glucanos/química , Oligosacáridos/química , Xilanos/química , alfa-L-Fucosidasa/metabolismo , Asialoglicoproteínas/metabolismo , Bifidobacterium/enzimología , Fetuínas/metabolismo , Fucosa/metabolismo , Gangliósidos/metabolismo , Glucanos/metabolismo , Glucolípidos/química , Glucolípidos/metabolismo , Mutación , Oligosacáridos/metabolismo , Plantas/química , Ingeniería de Proteínas , Xilanos/metabolismo , alfa-L-Fucosidasa/genética
5.
Biochem J ; 473(4): 463-72, 2016 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-26621872

RESUMEN

Exo-ß-D-glucosaminidase (EC 3.2.1.165) from Photobacterium profundum (PpGlcNase) is an inverting GH (glycoside hydrolase) belonging to family 9. We have determined the three-dimensional structure of PpGlcNase to describe the first structure-function relationship of an exo-type GH9 glycosidase. PpGlcNase has a narrow and straight active-site pocket, in contrast with the long glycan-binding cleft of a GH9 endoglucanase. This is because PpGlcNase has a long loop, which blocks the position corresponding to subsites -4 to -2 of the endoglucanase. The pocket shape of PpGlcNase explains its substrate preference for a ß1,4-linkage at the non-reducing terminus. Asp(139), Asp(143) and Glu(555) in the active site were located near the ß-O1 hydroxy group of GlcN (D-glucosamine), with Asp(139) and Asp(143) holding a nucleophilic water molecule for hydrolysis. The D139A, D143A and E555A mutants significantly decreased hydrolytic activity, indicating their essential role. Of these mutants, D139A exclusively exhibited glycosynthase activity using α-GlcN-F (α-D-glucosaminyl fluoride) and GlcN as substrates, to produce (GlcN)2. Using saturation mutagenesis at Asp(139), we obtained D139E as the best glycosynthase. Compared with the wild-type, the hydrolytic activity of D139E was significantly suppressed (<0.1%), and the F(-)-release activity also decreased (<3%). Therefore the glycosynthase activity of D139E was lower than that of glycosynthases created previously from other inverting GHs. Mutation at the nucleophilic water holder is a general strategy for creating an effective glycosynthase from inverting GHs. However, for GH9, where two acidic residues seem to share the catalytic base role, mutation of Asp(139) might inevitably reduce F(-)-release activity.


Asunto(s)
Glicósido Hidrolasas/química , Hexosaminidasas/química , Secuencia de Aminoácidos , Cristalografía por Rayos X , Glicósido Hidrolasas/genética , Hexosaminidasas/genética , Modelos Moleculares , Datos de Secuencia Molecular , Mutagénesis , Conformación Proteica , Homología de Secuencia de Aminoácido
6.
Glycobiology ; 26(11): 1235-1247, 2016 11.
Artículo en Inglés | MEDLINE | ID: mdl-27550195

RESUMEN

Fucα1-2 Gal linkages, or H-antigens, constitute histo-blood group antigens and are involved in various physiological processes. In addition, recent studies have shown that the H-antigen-containing glycans play an important role, not only in establishing harmonious relationship between gut microbes and the host, but also in preventing gut dysbiosis-related diseases. Therefore, development of an efficient method for introducing Fuc residue at Gal residue at the nonreducing end of glycans via α-(1→2) linkage is desired for research as well as medicinal purposes. In this study, we succeeded in derivatizing inverting 1,2-α-l-fucosidase (AfcA) into a highly efficient 1,2-α-l-fucosynthase. The synthase specifically synthesized H type 1-, type 2-, type 3- and type 4-chain-containing oligosaccharides with yields of 57-75% based on acceptor depletion. The synthase was also able to specifically introduce Fuc residues into Lewis a/x antigens to produce Lewis b/y antigens, with yields of 43% and 62%, respectively. In addition, the enzyme efficiently introduced H-antigens into sugar chains of porcine gastric mucins, as revealed by lectin blotting and mass spectroscopy analysis of the sugars. Detailed acceptor specificity analysis using various monosaccharides and oligosaccharides unraveled unique substrate recognition feature of this synthase at the subsite (+1), which can be explained by our previous X-ray crystallographic study of AfcA. These results show that the synthase developed in this study could serve as an alternative to other H-antigen synthesis methods involving α-1,2-fucosyltransferases and retaining α-fucosidase.


Asunto(s)
Antígenos Bacterianos/metabolismo , Glicoproteínas/metabolismo , Oligosacáridos/metabolismo , Azúcares/metabolismo , alfa-L-Fucosidasa/metabolismo , Antígenos Bacterianos/química , Bifidobacterium bifidum/enzimología , Biocatálisis , Conformación de Carbohidratos , Glicoproteínas/química , Modelos Moleculares , Oligosacáridos/química , Azúcares/química
7.
J Biol Chem ; 288(35): 25194-25206, 2013 Aug 30.
Artículo en Inglés | MEDLINE | ID: mdl-23843461

RESUMEN

Infant gut-associated bifidobacteria possess species-specific enzymatic sets to assimilate human milk oligosaccharides, and lacto-N-biosidase (LNBase) is a key enzyme that degrades lacto-N-tetraose (Galß1-3GlcNAcß1-3Galß1-4Glc), the main component of human milk oligosaccharides, to lacto-N-biose I (Galß1-3GlcNAc) and lactose. We have previously identified LNBase activity in Bifidobacterium bifidum and some strains of Bifidobacterium longum subsp. longum (B. longum). Subsequently, we isolated a glycoside hydrolase family 20 (GH20) LNBase from B. bifidum; however, the genome of the LNBase(+) strain of B. longum contains no GH20 LNBase homolog. Here, we reveal that locus tags BLLJ_1505 and BLLJ_1506 constitute LNBase from B. longum JCM1217. The gene products, designated LnbX and LnbY, respectively, showed no sequence similarity to previously characterized proteins. The purified enzyme, which consisted of LnbX only, hydrolyzed via a retaining mechanism the GlcNAcß1-3Gal linkage in lacto-N-tetraose, lacto-N-fucopentaose I (Fucα1-2Galß1-3GlcNAcß1-3Galß1-4Glc), and sialyllacto-N-tetraose a (Neu5Acα2-3Galß1-3GlcNAcß1-3Galß1-4Gal); the latter two are not hydrolyzed by GH20 LNBase. Among the chromogenic substrates examined, the enzyme acted on p-nitrophenyl (pNP)-ß-lacto-N-bioside I (Galß1-3GlcNAcß-pNP) and GalNAcß1-3GlcNAcß-pNP. GalNAcß1-3GlcNAcß linkage has been found in O-mannosyl glycans of α-dystroglycan. Therefore, the enzyme may serve as a new tool for examining glycan structures. In vitro refolding experiments revealed that LnbY and metal ions (Ca(2+) and Mg(2+)) are required for proper folding of LnbX. The LnbX and LnbY homologs have been found only in B. bifidum, B. longum, and a few gut microbes, suggesting that the proteins have evolved in specialized niches.


Asunto(s)
Proteínas Bacterianas/química , Bifidobacterium/enzimología , Glicósido Hidrolasas/química , Oligosacáridos/química , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Bifidobacterium/genética , Calcio/química , Calcio/metabolismo , Genes Bacterianos/fisiología , Glicósido Hidrolasas/genética , Glicósido Hidrolasas/metabolismo , Humanos , Lactante , Magnesio/química , Magnesio/metabolismo , Oligosacáridos/genética , Oligosacáridos/metabolismo , Especificidad por Sustrato
8.
J Biol Chem ; 287(20): 16709-19, 2012 May 11.
Artículo en Inglés | MEDLINE | ID: mdl-22451675

RESUMEN

α-L-fucosyl residues attached at the non-reducing ends of glycoconjugates constitute histo-blood group antigens Lewis (Le) and ABO and play fundamental roles in various biological processes. Therefore, establishing a method for synthesizing the antigens is important for functional glycomics studies. However, regiospecific synthesis of glycosyl linkages, especially α-L-fucosyl linkages, is quite difficult to control both by chemists and enzymologists. Here, we generated an α-L-fucosynthase that specifically introduces Le(a) and Le(x) antigens into the type-1 and type-2 chains, respectively; i.e. the enzyme specifically accepts the disaccharide structures (Galß1-3/4GlcNAc) at the non-reducing ends and attaches a Fuc residue via an α-(1,4/3)-linkage to the GlcNAc. X-ray crystallographic studies revealed the structural basis of this strict regio- and acceptor specificity, which includes the induced fit movement of the catalytically important residues, and the difference between the active site structures of 1,3-1,4-α-L-fucosidase (EC 3.2.1.111) and α-L-fucosidase (EC 3.2.1.51) in glycoside hydrolase family 29. The glycosynthase developed in this study should serve as a potentially powerful tool to specifically introduce the Le(a/x) epitopes onto labile glycoconjugates including glycoproteins. Mining glycosidases with strict specificity may represent the most efficient route to the specific synthesis of glycosidic bonds.


Asunto(s)
Proteínas Bacterianas/química , Bifidobacterium/enzimología , Fucosa/química , Fucosiltransferasas/química , Oligosacáridos/química , Proteínas Bacterianas/genética , Bifidobacterium/genética , Dominio Catalítico , Epítopos/química , Fucosiltransferasas/genética , Humanos , Antígenos del Grupo Sanguíneo de Lewis
9.
Phys Chem Chem Phys ; 15(14): 5097-107, 2013 Apr 14.
Artículo en Inglés | MEDLINE | ID: mdl-23450176

RESUMEN

Metallic titanium (Ti) particles treated with N2 plasma via the barrel-plasma-treatment system were thoroughly evaluated, to investigate changes in physical and chemical properties resulting from the treatment. The color of the Ti particles changed from gray to uniform brown upon plasma-treatment, indicating good surface uniformity. Depth profiling using X-ray photoelectron spectroscopy showed that the nitrogen implanted by plasma-treatment formed Ti-N bonds at or near the surface of the particles, resulting in the formation of a stoichiometric TiN layer. It was determined from cross-sectional transmission electron microscopy and nanobeam diffraction measurements that the resulting TiN layer had two different structures. Nanoindentation data showed that the surface of a treated sample was about five times harder than that of untreated particles.

10.
Biochem J ; 444(3): 437-43, 2012 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-22435672

RESUMEN

BcChi-A, a GH19 chitinase from the moss Bryum coronatum, is an endo-acting enzyme that hydrolyses the glycosidic bonds of chitin, (GlcNAc)(n) [a ß-1,4-linked polysaccharide of GlcNAc (N-acetylglucosamine) with a polymerization degree of n], through an inverting mechanism. When the wild-type enzyme was incubated with α-(GlcNAc)2-F [α-(GlcNAc)(2) fluoride] in the absence or presence of (GlcNAc)(2), (GlcNAc)(2) and hydrogen fluoride were found to be produced through the Hehre resynthesis-hydrolysis mechanism. To convert BcChi-A into a glycosynthase, we employed the strategy reported by Honda et al. [(2006) J. Biol. Chem. 281, 1426-1431; (2008) Glycobiology 18, 325-330] of mutating Ser(102), which holds a nucleophilic water molecule, and Glu(70), which acts as a catalytic base, producing S102A, S102C, S102D, S102G, S102H, S102T, E70G and E70Q. In all of the mutated enzymes, except S102T, hydrolytic activity towards (GlcNAc)(6) was not detected under the conditions we used. Among the inactive BcChi-A mutants, S102A, S102C, S102G and E70G were found to successfully synthesize (GlcNAc)(4) as a major product from α-(GlcNAc)(2)-F in the presence of (GlcNAc)(2). The S102A mutant showed the greatest glycosynthase activity owing to its enhanced F(-) releasing activity and its suppressed hydrolytic activity. This is the first report on a glycosynthase that employs amino sugar fluoride as a donor substrate.


Asunto(s)
Briófitas/enzimología , Quitinasas/metabolismo , Proteínas de Plantas/metabolismo , Briófitas/genética , Quitinasas/química , Quitinasas/genética , Cristalografía por Rayos X , Mutación/fisiología , Proteínas de Plantas/química , Proteínas de Plantas/genética , Estructura Secundaria de Proteína
11.
Glycobiology ; 22(3): 345-51, 2012 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-21930651

RESUMEN

A class IV chitinase belonging to the glycoside hydrolase 19 family from Nepenthes alata (NaCHIT1) was expressed in Escherichia coli. The enzyme exhibited weak activity toward polymeric substrates and significant activity toward (GlcNAc)(n) [ß-1,4-linked oligosaccharide of GlcNAc with a polymerization degree of n (n = 4-6)]. The enzyme hydrolyzed the third and fourth glycosidic linkages from the non-reducing end of (GlcNAc)(6). The pH optimum of the enzymatic reaction was 5.5 at 37°C. The optimal temperature for activity was 60°C in 50 mM sodium acetate buffer (pH 5.5). The anomeric form of the products indicated that it was an inverting enzyme. The k(cat)/K(m) of the (GlcNAc)(n) hydrolysis increased with an increase in the degree of polymerization. Amino acid sequence alignment analysis between NaCHIT1 and a class IV chitinase from a Picea abies (Norway spruce) suggested that the deletion of four loops likely led the enzyme to optimize the (GlcNAc)(n) hydrolytic reaction rather than the hydrolysis of polymeric substrates.


Asunto(s)
Caryophyllaceae/enzimología , Quitinasas/biosíntesis , Proteínas de Plantas/biosíntesis , Acetilglucosamina/química , Secuencia de Aminoácidos , Dominio Catalítico , Quitinasas/química , Quitinasas/aislamiento & purificación , Cromatografía de Afinidad , Cromatografía Líquida de Alta Presión , Clonación Molecular , Expresión Génica , Concentración de Iones de Hidrógeno , Hidrólisis , Cinética , Datos de Secuencia Molecular , Oligosacáridos/química , Oligosacáridos/aislamiento & purificación , Proteínas de Plantas/química , Proteínas de Plantas/aislamiento & purificación , Estructura Secundaria de Proteína , Proteínas Recombinantes de Fusión/biosíntesis , Proteínas Recombinantes de Fusión/química , Proteínas Recombinantes de Fusión/aislamiento & purificación , Homología de Secuencia de Aminoácido
12.
Glycobiology ; 21(4): 503-11, 2011 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-21098515

RESUMEN

A glycoside hydrolase (GH) gene from Photobacterium profundum SS9 (PBPRA0520) belonging to GH family 9 was expressed in Escherichia coli. The protein was expressed with the intact N-terminal sequence, suggesting that it is an intracellular enzyme. The recombinant protein showed hydrolytic activity toward chitobiose [(GlcN)(2)] and cellobiose (CG(2)) in various disaccharides. This protein also released 4-nitrophenol (PNP) from both 4-nitrophenyl-ß-D-glucosaminide (GlcN-PNP) and 4-nitrophenyl-ß-D-glucoside (Glc-PNP). The hydrolytic pattern observed in chitooligosaccharides and cellooligosaccharides suggested that the reaction proceeded from the nonreducing end in an exo-type manner. Time-dependent (1)H-nuclear magnetic resonance (NMR) analysis of the anomeric form of the enzymatic reaction products indicated that the protein is an inverting enzyme. k(cat)/K(m) of (GlcN)(2) hydrolysis was 14 times greater than that of CG(2) hydrolysis. These results suggested that the protein is an exo-ß-D-glucosaminidase (EC 3.2.1.165) rather than a glucan 1,4-ß-D-glucosidase (EC 3.2.1.74). Based on the results, we suggest that the function of conserved GH9 proteins in the chitin catabolic operon is to cleave a (GlcN)(2)-phosphate derivative by hydrolysis during intracellular chitooligosaccharide catabolism in Vibrionaceae.


Asunto(s)
Hexosaminidasas/biosíntesis , Photobacterium/enzimología , Proteínas Recombinantes/biosíntesis , Cromatografía Líquida de Alta Presión , Cromatografía en Capa Delgada , Disacáridos/metabolismo , Pruebas de Enzimas , Estabilidad de Enzimas , Hexosaminidasas/química , Hexosaminidasas/aislamiento & purificación , Concentración de Iones de Hidrógeno , Hidrólisis , Cinética , Espectroscopía de Resonancia Magnética , Peso Molecular , Proteínas Recombinantes/química , Proteínas Recombinantes/aislamiento & purificación , Temperatura
13.
Int J Biol Macromol ; 148: 1021-1028, 2020 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-31954787

RESUMEN

We investigated the physicochemical properties of starches extracted from Vigna angularis variants Noto-dainagon, Kyoto-dainagon, dainagon, and erimo-type adzuki beans. The particle size was larger in the Noto-dainagon starch than in the other starches, but all starches displayed a C-type crystal structure in the X-ray diffraction analysis. The onset and peak temperatures of gelatinization were approximately 7 °C lower in the Noto-dainagon and Kyoto-dainagon starches than in the dainagon and adzuki bean starches. The dainagon and adzuki bean starches also demonstrated lower swelling power at 60 °C than the other starches. The rapid visco-analyser curves of all starches showed no breakdown during the heating process, and the final viscosities of the starches increased with decreasing temperature. The apparent amylose and phosphorus contents were highest in the Noto-dainagon starch (36.6% and 95.6 ppm, respectively). The branched- chain length degree of polymerization 6-12 was lowest in the adzuki bean starch. In vitro and in vivo analyses of the digestive properties indicated that dainagon starch was more indigestible than the other starches. We considered that dainagon starch was a potentially viable health-promoting ingredient.


Asunto(s)
Fenómenos Químicos , Almidón/química , Vigna/química , Amilosa/química , Animales , Hidrólisis , Masculino , Ratones , Peso Molecular , Tamaño de la Partícula , Fósforo , Análisis Espectral , Almidón/ultraestructura , Porcinos , Viscosidad
14.
J Food Sci ; 84(5): 1180-1187, 2019 May.
Artículo en Inglés | MEDLINE | ID: mdl-30990903

RESUMEN

Consumption of the common bean (Phaseolus vulgaris L.) is associated with beneficial effects on lipid and glucose metabolism; however, the influence of the bean processing method on these health benefits is not well understood. To investigate this, we processed red kidney beans (RKBs), a variety of the common bean, by roasting and boiling and compared the physiological effects of the two preparations in male C57BL/6N mice fed a high-fat diet (HFD). The two RKB preparations differed mainly in their resistant starch content (roasted, 24.5%; boiled, 3.1%). Four groups of mice were fed for 12 weeks on a normal diet or a HFD (45 kcal% fat) supplemented with 10% control chow (HFD control group), 10% roasted RKB, or 10% freeze-dried boiled RKB. We found that intake of roasted RKBs prevented hypercholesterolemia and increased fecal IgA and mucin content compared with the HFD control group, while intake of boiled RKBs improved glucose tolerance. Both RKB preparations suppressed the HFD-associated increase in plasma aspartate aminotransferase and alanine aminotransferase levels, which are markers of liver injury. Mice fed roasted RKBs showed significantly increased hepatic expression of cholesterol 7-alpha-monooxygenase mRNA, suggesting that cholesterol suppression may be due to enhanced bile acid biosynthesis. In contrast, mice fed boiled RKBs showed significantly increased cecal content of n-butyric acid, which may be related to the improved glucose tolerance in this group. These results indicate that the method by which RKBs are processed can profoundly affect their health benefits.


Asunto(s)
Dieta , Glucosa/metabolismo , Metabolismo de los Lípidos/fisiología , Obesidad/metabolismo , Phaseolus , Animales , Culinaria/métodos , Modelos Animales de Enfermedad , Hígado/enzimología , Hígado/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL
15.
J Appl Glycosci (1999) ; 66(2): 51-57, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-34354520

RESUMEN

We investigated the physicochemical properties of starches extracted from 8 lotus (Nelumbo nucifera Gaertn.) rhizomes harvested in different months (September 2012 to May 2013). The physicochemical properties of the lotus starches depended on the harvest date. The peak viscosity (PV) in the Rapid Visco-Analyser analysis, and the viscosity at 65 °C (V65) in the rotational viscometer analysis were significantly lower in SEP starch (extracted from the September-harvested sample) than in the other lotus starches. The Spearman's rank correlation coefficients of potassium ion (K) content vs. V65 and of K content vs. PV were 0.905 and 0.714, respectively, indicating that potassium ions are important for expressing the pasting properties of lotus starch. Principal component analysis suggested that the potassium, magnesium, calcium, and phosphorus contents are important for displaying both the pasting and gelatinization properties of the lotus starches. Meanwhile, the cluster analysis revealed that physicochemical properties of the SEP starch were different from those of the starches harvested in other months.

16.
Glycobiology ; 18(4): 325-30, 2008 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-18263897

RESUMEN

The tyrosine residue Y198 is known to support a nucleophilic water molecule with the general base residue, D263, in the reducing-end xylose-releasing exo-oligoxylanase (Rex). A mutation in the tyrosine residue changing it into phenylalanine caused a drastic decrease in the hydrolytic activity and a small increase in the F(-) releasing activity from alpha-xylobiosyl fluoride in the presence of xylose. In contrast, mutations at D263 resulted in the decreased F(-) releasing activity. As a result of the high F(-) releasing activity and low hydrolytic activity, Y198F of Rex accumulates a large amount of product during the glycosynthase reaction. We propose a novel method for producing a glycosynthase from an inverting glycoside hydrolase by mutating a residue that holds the nucleophilic water molecule with the general base residue while keeping the general base residue intact.


Asunto(s)
Glicósido Hidrolasas/metabolismo , Glicosiltransferasas/metabolismo , Xilosidasas/genética , Xilosidasas/metabolismo , Sustitución de Aminoácidos/fisiología , Glicósido Hidrolasas/genética , Glicosiltransferasas/genética , Cinética , Modelos Biológicos , Modelos Moleculares , Mutagénesis Sitio-Dirigida , Proteínas Mutantes/metabolismo , Fenilalanina/genética , Especificidad por Sustrato/genética , Factores de Tiempo , Tirosina/genética , Tirosina/fisiología
17.
FEBS Lett ; 582(27): 3739-43, 2008 Nov 12.
Artículo en Inglés | MEDLINE | ID: mdl-18845150

RESUMEN

Fucosyloligosaccharides have great therapeutic potential. Here we present a new route for synthesizing a Fucalpha1,2Gal linkage by introducing glycosynthase technology into 1,2-alpha-l-fucosidase. The enzyme adopts a unique reaction mechanism, in which asparagine-423 activated by aspartic acid-766 acts as a base while asparagine-421 fixes both a catalytic water and glutamic acid-566 (an acid) in the proper orientations. Glycosynthase activity of N421G, N423G, and D766G mutants was examined using beta-fucosyl fluoride and lactose, and among them, the D766G mutant most effectively synthesized 2'-fucosyllactose. 1,2-alpha-l-Fucosynthase is the first glycosynthase derived from an inverting alpha-glycosidase and from a glycosidase with an unusual reaction mechanism.


Asunto(s)
Proteínas Bacterianas/química , Trisacáridos/biosíntesis , alfa-L-Fucosidasa/química , Proteínas Bacterianas/biosíntesis , Proteínas Bacterianas/genética , Bifidobacterium/enzimología , Catálisis , Hidrólisis , Mutagénesis Sitio-Dirigida , Mutación , Conformación Proteica , alfa-L-Fucosidasa/biosíntesis , alfa-L-Fucosidasa/genética
18.
Structure ; 12(6): 937-47, 2004 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-15274915

RESUMEN

Vibrio proteolyticus chitobiose phosphorylase (ChBP) belongs to glycosyl transferase family 36 (GT-36), and catalyzes the reversible phosphorolysis of chitobiose into alpha-GlcNAc-1-phosphate and GlcNAc with inversion of the anomeric configuration. As the first known structures of a GT-36 enzyme, we determined the crystal structure of ChBP in a ternary complex with GlcNAc and SO(4). It is also the first structures of an inverting phosphorolytic enzyme in a complex with a sugar and a sulfate ion, and reveals a pseudo-ternary complex structure of enzyme-sugar-phosphate. ChBP comprises a beta sandwich domain and an (alpha/alpha)(6) barrel domain, constituting a distinctive structure among GT families. Instead, it shows significant structural similarity with glycoside hydrolase (GH) enzymes, glucoamylases (GH-15), and maltose phosphorylase (GH-65) in clan GH-L. The structural similarity reported here, together with distant sequence similarities between ChBP and GHs, led to the reclassification of family GT-36 into a novel GH family, namely GH-94.


Asunto(s)
Glicosiltransferasas/química , N-Acetilglucosaminiltransferasas/química , Vibrio/enzimología , Secuencia de Aminoácidos , Proteínas Bacterianas , Sitios de Unión , Carbohidratos/química , Cristalografía por Rayos X , Dimerización , Glucano 1,4-alfa-Glucosidasa/química , Glucosiltransferasas/química , Glicósido Hidrolasas/química , Modelos Moleculares , Datos de Secuencia Molecular , Unión Proteica , Conformación Proteica , Pliegue de Proteína , Estructura Cuaternaria de Proteína , Estructura Secundaria de Proteína , Estructura Terciaria de Proteína , Homología de Secuencia de Aminoácido , Programas Informáticos , Especificidad por Sustrato , Sulfatos/química
19.
J Biochem ; 160(2): 93-100, 2016 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-26908157

RESUMEN

We created a glycosynthase from a GH19 chitinase from rye seeds (RSC-c), that has a long-extended binding cleft consisting of eight subsites; -4, -3, -2, -1, +1, +2, +3 and +4. When wild-type RSC-c was incubated with α-(GlcNAc)3-F [α-(GlcNAc)3 fluoride], (GlcNAc)3 and hydrogen fluoride were produced through the Hehre resynthesis-hydrolysis mechanism. Glu89, which acts as a catalytic base, and Ser120, which fixes a nucleophilic water molecule, were mutated to produce two single mutants, E89G and S120A, and a double mutant, E89G/S120A. E89G only produced a small amount of (GlcNAc)7 from α-(GlcNAc)3-F in the presence of (GlcNAc)4 S120A, with the highest F(-)-releasing activity, produced a larger amount of (GlcNAc)7, a fraction of which was decomposed by its own residual hydrolytic activity. However, the double mutant E89G/S120A, of which the hydrolytic activity was completely abolished while its F(-)-releasing activity was only moderately affected, produced the largest amount of (GlcNAc)7 from α-(GlcNAc)3-F and (GlcNAc)4 without decomposition. We concluded that E89G/S120A was an efficient glycosynthase, that enabled the addition of a three-sugar unit.


Asunto(s)
Proteínas Bacterianas/química , Quitinasas/química , Modelos Moleculares , Ralstonia/química , Dominio Catalítico
20.
J Appl Glycosci (1999) ; 63(3): 61-68, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-34354484

RESUMEN

We investigated the physicochemical properties of starches from rhizomes of two lotus (Nelumbo nucifera Gaertn.) cultivars, Shinashirobana cultivar and Kanasumi-line No. 20, harvested at the same farm in Japan. A rapid visco analyser analysis indicated that pasting temperatures of the starches from Shinashirobana cultivar and Kanasumi-line No. 20 were 62.1 and 66.5 °C, respectively, and the peak viscosities of the starch of both lotuses were similar 244 and 240 RVU, respectively. The starch from the Kanasumi-line No. 20 at 60 °C had low viscosity, 16.2 mPa∙s, but the starch from Shinashirobana cultivar had higher viscosity, 2,720 mPa∙s, at 60 °C. The onset and peak temperatures of the differential scanning calorimetry (DSC) curve of the starch from Shinashirobana cultivar were 4-5 °C lower than those of the starch from Kanasumi-line No. 20, although both exhibited similar ΔH values (13.4 and 11.6 J/g). The distribution patterns of the branched chain lengths of amylopectin in the two starches indicated that the rate of low-degree of polymerization (DP 5-12) of all branched chains was higher for the starch from Shinashirobana cultivar than that for the starch from Kanasumi-line No. 20. These results suggest that the increased rate of DP 5-12 in the starch from Shinashirobana cultivar is related to the higher viscosity of the starch.

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