Catalytic versatility of Bacillus pumilus .beta.-xylosidase: glycosyl transfer and hydrolysis promoted with .alpha.- and .beta.-D-xylosyl fluoride

Kasumi, Takafumi; Tsumuraya, Yoichi; Brewer, C. Fred; Kersters-Hilderson, H; Claeyssens, Marc; Hehre, Edward J.

doi:10.1021/bi00385a009

Cited by 43 publications

(32 citation statements)

References 33 publications

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“…Kasumi et al have explained that it requires the reversal of the roles of catalytic groups to continue the reaction of transglycosylation and hydrolysis of 4--xylobiose (or 4--xylobiosyl fluoride) by -xylosidase, and that reaction A occurs beyond the requirement of the principle of microscopic reversibility. 66) This description intimates an important consideration that the concerted reaction mechanism may be in conflict with the principle. However, if the disposition of functional groups reverts Reactions I and II are the hydrolytic and synthesis reactions, respectively.…”

Section: Reversible Reaction Of Glycosidasesmentioning

confidence: 82%

“…The same concerted mechanism has been applied to several inverting enzymes, including glucoamylase 62) and glucodextranase, 62) trehalase, 64,65) and -xylosidase. 66) As an example of the reaction for the concerted mechanism, the hydrolytic and synthesis reactions of ,-trehalose by trehalase particularly taken from among the abovementioned inverting glycosidases are shown Fig. 9.…”

Section: Reversible Reaction Of Glycosidasesmentioning

confidence: 99%

“…10). [67][68][69][70][71][72][73] William and Withers 69) have cited it as an example of the mechanism for the hydrolysis of ''wrong'' anomeric fluoride, meaning mistaken recognition of anomeric configuration, in the synthesis and hydrolysis of 4--xylobiose formed from -xylosyl fluoride 66) for inverting -xylosidase (Fig. 10A).…”

Section: Reversible Reaction Of Glycosidasesmentioning

confidence: 99%

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A Historical Perspective for the Catalytic Reaction Mechanism of Glycosidase; So As to Bring about Breakthrough in Confusing Situation

Chiba

2012

Bioscience, Biotechnology, and Biochemistry

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Various catalytic reaction models have been proposed as the reaction mechanisms of glycosidases, but a reasonable and unitary model capable of interpreting both ''inverting'' and ''retaining'' glycosidase reactions remains to be established. As for the models proposed to date, the nucleophilic displacement mechanism and the oxocarbenium ion intermediate mechanism are widely known, but recently the former is widely accepted, and so the general tendency of world opinion appears to favor it. This reaction model, however, is considered to comprise some inconsistencies that cannot be neglected from the viewpoint of reactivity in organic chemistry. While the nucleophilic displacement mechanism is often applied to reactions of glycosidases, it appears unlikely that such reactions actually occur. This review argues that the oxocarbenium ion intermediate reaction mechanism is more rational than the nucleophilic displacement reaction mechanism, as the action mode of glycosidases and related enzymes.

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Section: Reversible Reaction Of Glycosidasesmentioning

confidence: 82%

Section: Reversible Reaction Of Glycosidasesmentioning

confidence: 99%

Section: Reversible Reaction Of Glycosidasesmentioning

confidence: 99%

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A Historical Perspective for the Catalytic Reaction Mechanism of Glycosidase; So As to Bring about Breakthrough in Confusing Situation

Chiba

2012

Bioscience, Biotechnology, and Biochemistry

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“…A number of detailed studies on the mechanism of p-xylosidases have been made in the past and two types of mechanisms have been found: inverting for a Bacillus pumilus /?-xylosidase (Kersters-Hilderson et al, 1976;Kasumi et al, 1987). and retaining with high transglycosylating activity for a Penicilliurn wortmanni enzyme (Deleyn et al, 1985).…”

mentioning

confidence: 99%

Stereochemical Course and Reaction Products of the Action of β‐Xylosidase from Thermoanaerobacterium saccharolyticum Strain B6A‐RI

Armand

Vieille

Gey

et al. 1996

European Journal of Biochemistry

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P-Xylosidases are grouped in families 39 and 43 of a general classification of glycosyl hydrolases based on amino acid sequence similarities [Henrissat, B. & Bairoch, A. (1993) Biochem. J. 293,. The P-xylosidase from Butyrivibrio fibrisolvens, which belongs to family 43, has been shown to operate by a molecular mechanism which results in the inversion of the anomeric configuration [Braun, C., Meinke, A., Ziser, L. & Withers, S. G. (1994) Anal. Biochem. 212, 259-2621, Thermounaerohacterium saccharolyticum B6A-RI P-xylosidase which belongs to family 39 was purified as a recombinant enzyme from Escherichia coli. The stereochemistry of the hydrolysis of p-nitrophenyl P-D-xylopyranoside was followed by 'H NMR. The spectrum recorded after 2 h hydrolysis showed a large signal centred at 4.47 ppm ( J = 10 Hz) assignable to H1 of free P-xylose with a small amount of a-xylose (5.05 ppm, J = 3 Hz) attributable to mutarotation. This result indicates that 7: saccharolyticum P-xylosidase operates with overall retention of the anomeric configuration. This result, with the lack of sequence similarity between the two families of P-xylosidases, suggests that these two families have major differences in their active-site geometries. Consistent with its retaining mechanism, P-xylosidase of 7: saccharolyticum B6A-RI also displayed transglycosylating activity : reverse-phase HPLC showed approximately 30% conversion of p-nitrophenyl P-D-xylopyranoside into a number of higher nitrophenyl oligosaccharides after 5 min incubation with the enzyme. The structure of the most abundant oligosaccharides could be determined by total correlation spectroscopy NMR and showed that the enzyme can build /?-1,4, /?-1,3-and P-1,2-linked xylo-oligosaccharides.

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“…␣-glycosyl fluoride by a ␤-glycoside-hydrolyzing enzyme) is hydrolyzed in the presence of the acceptor molecule. Several inverting enzymes have been reported to hydrolyze the opposite anomer of glycosyl fluoride (6,11,(32)(33)(34). The mechanism of the reaction, illustrated in Fig.…”

Section: Discussionmentioning

confidence: 99%

The First Glycosynthase Derived from an Inverting Glycoside Hydrolase

Honda

Kitaoka

2006

Journal of Biological Chemistry

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Reducing end xylose-releasing exooligoxylanase (Rex, EC 3.2.1.156) is an inverting GH that hydrolyzes xylooligosaccharides (>X 3 ) to release X 1 at their reducing end. The wild-type enzyme exhibited the Hehre resynthesis hydrolysis mechanism, in which ␣-X 2 F was hydrolyzed to X 2 and HF in the presence of X 1 as an acceptor molecule. However, the transglycosidation product (X 3 ) was not detectable in the reaction. To convert reducing end xylosereleasing exooligoxylanase to glycosynthase, derivatives with mutations in the catalytic base (Asp-263) were constructed by saturation random mutagenesis. Nine amino acid residue mutants (Asp-263 to Gly, Ala, Val, Thr, Leu, Asn, Cys, Pro, or Ser) were found to possess glycosynthase activity forming X 3 from ␣-X 2 F and X 1 . Among them, D263C showed the highest level of X 3 production, and D263N exhibited the fastest consumption of ␣-X 2 F. The D263C mutant showed 10-fold lower hydrolytic activity than D263N, resulting in the highest yield of X 3 . X 2 was formed from the early stage of the reaction of the D263C mutant, indicating that a portion of the X 3 formed by condensation was hydrolyzed before its release from the enzyme. To acquire glycosynthase activity from inverting enzymes, it is important to minimize the decrease in F ؊ -releasing activity while maximizing the decrease in the hydrolytic activity. The present study expands the possibility of conversion of glycosynthases from inverting enzymes.Glycoside hydrolases (GH) 2 are generally categorized into two types, retaining and inverting enzymes, based on changes in the anomeric configurations during the reactions (1-5). The reaction mechanisms of typical retaining and inverting enzymes are illustrated in Fig. 1. Both types of enzyme have two acidic catalytic residues acting as a general acid (a proton donor) and a general base (a nucleophile). In the retaining GH reaction, first, in concert, the general acid donates a proton to the glycosyl oxygen atom, and the nucleophile attacks the anomeric center, producing a covalent-bound intermediate of the nucleophile with Walden inversion. Next, the intermediate undergoes inverting hydrolysis. The reaction of the inverting GH is similar but differs in the reagent attacking the anomeric center; in this case, a water molecule activated by the catalytic base attacks the anomeric center to hydrolyze the glycoside with anomeric inversion.In 1979, Hehre et al. (6) reported that ␤-amylase hydrolyzed ␤-maltosyl fluoride, the opposite anomer of the glycosides to be hydrolyzed, into maltose and fluoride ions. Later, various inverting enzymes were shown to hydrolyze the "wrong" glycosyl fluorides (7-10), suggesting that the reaction is common among inverting GHs. Instead of simple hydrolysis, the reaction mechanism consists of two steps. In the first step a new glycoside of the correct anomer forms from the wrong glycosyl fluoride and an acceptor by Walden inversion. The new glycoside is then hydrolyzed with anomeric inversion at the same site on the enzyme before it is release...

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Catalytic versatility of Bacillus pumilus .beta.-xylosidase: glycosyl transfer and hydrolysis promoted with .alpha.- and .beta.-D-xylosyl fluoride

Cited by 43 publications

References 33 publications

A Historical Perspective for the Catalytic Reaction Mechanism of Glycosidase; So As to Bring about Breakthrough in Confusing Situation

A Historical Perspective for the Catalytic Reaction Mechanism of Glycosidase; So As to Bring about Breakthrough in Confusing Situation

Stereochemical Course and Reaction Products of the Action of β‐Xylosidase from Thermoanaerobacterium saccharolyticum Strain B6A‐RI

The First Glycosynthase Derived from an Inverting Glycoside Hydrolase

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