-Mannosynthase: Synthesis of -Mannosides with a Mutant -Mannosidase

Nashiru, Oyekanmi; Zechel, David L.; Stoll, Dominik; Mohammadzadeh, Taraneh; Warren, R. A. J.; Withers, Stephen G.

doi:10.1002/1521-3773(20010119)40:2<417::aid-anie417>3.3.co;2-m

Cited by 31 publications

(43 citation statements)

References 38 publications

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“…To the best of our knowledge, almost a dozen of glycoside hydrolases (GH), belonging to seven different GH families from bacteria, eukarya and archaea, have been modified as efficient glycosynthases; among them mesophilic and thermophilic β-glycosidases [222][223][224] the latter acting also at acidic pH with great reactivation rate [225], endo-acting enzymes transferring more than one sugar [226][227][228][229][230], a modification of replacing aminoacid residue with increased reactivity [231], a mannosidase [232,233], the first α-glucosidase [234], and a β-galactosidase [235] were all reported.…”

Section: Glycosynthasesmentioning

confidence: 87%

Glycosyl Hydrolases and Glycosyltransferases in the Synthesis of Oligosaccharides

Trincone¹,

Giordano

2006

COC

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Glycobiology and related disciplines have received an enormous interest in recent years as they shed new light on the functional roles of carbohydrates in biological events leading to the understanding of mechanisms of important pathologies and to the development of new therapeutics. Although carbohydrate can be isolated from natural sources, the synthetic strategy plays its own role allowing access to larger quantities of structurally defined material and entry to analogs of naturally occurring structures. Nowadays, the bottleneck in this field is represented by some limitations of the potential of carbohydrate containing molecules because their complex structures make classical chemical synthesis very difficult.The synthesis of oligosaccharides have to face with three main snags: (i) reactivity of the leaving group on the monosaccharide acting as donor; (ii) regioselectivity towards a single hydroxyl group on the acceptor molecule; (iii) stereoselectivity in forming pure anomers of the new glycosidic product. The protecting-group manipulations that are needed for the stereocontrol of the products are demanding procedures thus yields and selectivity are lowered hindering the efficient production of oligosaccharides needed for biological testing.A particular benefit of the renewed interest for sugar chemistry has been the attention of scientific community to the biological methodologies in the production of oligosaccharides, an area which emerged in recent decades.In the carbohydrate field different enzymes were used for diverse purposes but enzymatic strategies for high-yield and stereospecific construction of glycosidic bonds are based on the action of two types of enzymes: glycosyl hydrolases (endo-and exo-glycosidases) and glycosyltransferases. Glycosyl hydrolases in the cells are responsible for the cleavage of glycosidic linkages; the exo-glycosidase are involved for glycan processing during in vivo glycoprotein synthesis. The glycosyltransferases are instead responsible in vivo for the synthesis of most cell-surface glycoconjugates.This review deals with the application of different types of glycosyl hydrolases. Elegant examples concerning the use of genetically modified representatives of glycosyl hydrolases (glycosynthases and thioglycoligases) will be also reported; some recent advances on the use of glycosyltransferases are also included.In compiling this review we were aware of the huge amount of excellent material published in the recent years on this topic, thus we will limit the covering of literature to the last decade. Attention will be devoted to the regioselectivity towards pyranosidic templates and to the yield of reactions. The molecular diversity obtained by the use of enzymes from different biological sources and the biological importance of the compounds synthesized will be focused as well.This review will put in evidence that glycosyl hydrolases and glycosyltransferases for the synthesis of the glycosidic linkages will play a relevant role in the next future as on the bench bio-catalysts ...

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Section: Glycosynthasesmentioning

confidence: 87%

Glycosyl Hydrolases and Glycosyltransferases in the Synthesis of Oligosaccharides

Trincone¹,

Giordano

2006

COC

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“…These results are in contrast to those for other glycosynthases, in which serine mutants are often more active than alanine mutants. 21,23,28,31) GH 10 glycosynthases formed polymer products from -X 2 F. The mechanism of polymer production is explained as follows. The glycosynthases producexylotetraosyl fluoride (-X 4 F) as the initial product by selfcondensation of -X 2 F. Then the resulting -X 4 F is utilized as the acceptor and/or donor substrate to elongate the chain length, and finally the polymer is generated to precipitate.…”

Section: Discussionmentioning

confidence: 99%

“…The reaction was first demonstrated with a -glucosidase belonging to glycoside hydrolase family 1 from Agrobacterium tumefaciens. 20) Subsequently, several glycosynthases derived from variousglycosidases have been reported from both exo- [21][22][23][24][25][26] and endo-hydrolases. [27][28][29][30][31][32][33] An -glycoside-forming glycosynthase was also demonstrated with an -glucosidase belonging to GH 31.…”

mentioning

confidence: 99%

Characterization of Glycosynthase Mutants Derived from Glycoside Hydrolase Family 10 Xylanases

Sugimura

Nishimoto

Kitaoka

2006

Bioscience, Biotechnology, and Biochemistry

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“…The narrow substrate specificity and the extremely low K i value of ManB make this protein an excellent candidate for chemoenzymatic utilization. Other mannosidases like the ␤-mannosidase from P. furiosus (9) and Man2A from C. fimi (34) have either a wider substrate FIG. 6.…”

Section: Kinetic Properties Of the Manb Proteinmentioning

confidence: 99%

Cloning and Heterologous Expression of a β- d -Mannosidase (EC 3.2.1.25)-Encoding Gene from Thermobifida fusca TM51

Béki

Nagy

Vanderleyden

et al. 2003

Appl Environ Microbiol

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Thermobifida fusca TM51, a thermophilic actinomycete isolated from composted horse manure, was found to produce a number of lignocellulose-degrading hydrolases, including endoglucanases, exoglucanases, endoxylanases, ␤-xylosidases, endomannanases, and ␤-mannosidases, when grown on cellulose or hemicellulose as carbon sources. ␤-Mannosidases (EC 3.2.1.25), although contributing to the hydrolysis of hemicellulose fractions, such as galacto-mannans, constitute a lesser-known group of the lytic enzyme systems due to their low representation in the proteins secreted by hemicellulolytic microorganisms. An expression library of T. fusca, prepared in Streptomyces lividans TK24, was screened for ␤-mannosidase activity to clone genes coding for mannosidases. One positive clone was identified, and a ␤-mannosidase-encoding gene (manB) was isolated. Sequence analysis of the deduced amino acid sequence of the putative ManB protein revealed substantial similarity to known mannosidases in family 2 of the glycosyl hydrolase enzymes. The calculated molecular mass of the predicted protein was 94 kDa, with an estimated pI of 4.87. S. lividans was used as heterologous expression host for the putative ␤-mannosidase gene of T. fusca. The purified gene product obtained from the culture filtrate of S. lividans was then subjected to more-detailed biochemical analysis. Temperature and pH optima of the recombinant enzyme were 53°C and 7.17, respectively. Substrate specificity tests revealed that the enzyme exerts only ␤-D-mannosidase activity. Its kinetic parameters, determined on para-nitrophenyl ␤-Dmannopyranoside (pNP-␤M) substrate were as follows: K m ‫؍‬ 180 M and V max ‫؍‬ 5.96 mol min ؊1 mg ؊1 ; the inhibition constant for mannose was K i ‫؍‬ 5.5 mM. Glucono-lacton had no effect on the enzyme activity. A moderate trans-glycosidase activity was also observed when the enzyme was incubated in the presence of pNP-␣M and pNP-␤M; under these conditions mannosyl groups were transferred by the enzyme from pNP-␤M to pNP-␣M resulting in the synthesis of small amounts (1 to 2%) of disaccharides.Thermobifida spp. are gram-positive, compost-and soil-inhabiting bacteria with broad degradative activity on plant cell wall constituents. Thermobifida fusca, the most extensively studied species of this genus, is the model organism of thermophilic, aerobic cellulolytic bacteria (48). While there are ample data on the cellulolytic system of T. fusca (8,24,30,47,48), the hemicellulolytic enzyme system of this species is still poorly characterized. Only one endoxylanase-and an endomannanase-encoding gene have been cloned to date (20,22), although the hemicellulolytic enzyme system of T. fusca may be as complex as the well-characterized cellulase system of this organism; the latter consists of three endoglucanases, two exoglucanases, one processive endoglucanase, and a cellobiase enzyme (23,43).The complexity of cell wall-degrading enzyme systems is a consequence of the complex nature of plant cell wall. Hemicelluloses act as linkers between lignin and cel...

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-Mannosynthase: Synthesis of -Mannosides with a Mutant -Mannosidase

Cited by 31 publications

References 38 publications

Glycosyl Hydrolases and Glycosyltransferases in the Synthesis of Oligosaccharides

Glycosyl Hydrolases and Glycosyltransferases in the Synthesis of Oligosaccharides

Characterization of Glycosynthase Mutants Derived from Glycoside Hydrolase Family 10 Xylanases

Cloning and Heterologous Expression of a β- d -Mannosidase (EC 3.2.1.25)-Encoding Gene from Thermobifida fusca TM51

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