Substrate Recognition Mechanism of α-1,6-Glucosidic Linkage Hydrolyzing Enzyme, Dextran Glucosidase from Streptococcus mutans

Hondoh, Hironori; Saburi, Wataru; Mori, Haruhide; Okuyama, Masayuki; Nakada, T.; Matsuura, Yoshiki; Kimura, Atsuo

doi:10.1016/j.jmb.2008.03.016

Cited by 63 publications

(77 citation statements)

References 44 publications

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“…Domain C (residues 466 to 539) assumes a ␤-sandwich fold composed of five strands packing against domain A and two shorter ␤-strands that are solvent exposed. A Ca 2ϩ is bound in domain A in a loop located just before the first helix in a binding site resembling that observed in SmGH13_31 (19). The Ca 2ϩ octahedral coordination shell comprises the side chains of Asp20, Asn22, Asp24, and Asp28, the carbonyl oxygen of Ile26, and a water molecule.…”

Section: Figmentioning

confidence: 82%

“…For LaGH13_31, adding EDTA to the crystallization conditions abolished crystal formation, and recently it has been shown that the presence of Ca 2ϩ enhances the thermostability of SmGH13_31 (26), supporting a structural role of this divalent ion in GH13_31. Interestingly, the water path between the active site and the surface of the enzyme, which was suggested to have functional significance as a water drain in SmGH13_31 (19), is also conserved in LaGH13_31 (see Fig. S5 in the supplemental material).…”

Section: Figmentioning

confidence: 99%

“…Both types of enzymes are highly regioselective, showing little or no activity toward glucosidic linkages other than ␣-1,6 (43,47,54,55). The only biochemically and structurally characterized GH13_31 with a glucan 1,6-␣-glucosidase specificity (G16G) is from Streptococcus mutans (SmGH13_31) (19,43). By comparison, the biochemical properties of three GH13_31 oligo-1,6-␣-glucosidases (O16Gs) from Bacillus thermoglucosidasius (Geobacillus thermoglucosidasius), Bacillus coagulans, and Bacillus cereus have been reported, and the structure of the last enzyme has been determined (43,47,54,55).…”

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confidence: 99%

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Enzymology and Structure of the GH13_31 Glucan 1,6-α-Glucosidase That Confers Isomaltooligosaccharide Utilization in the Probiotic Lactobacillus acidophilus NCFM

et al. 2012

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b Isomaltooligosaccharides (IMO) have been suggested as promising prebiotics that stimulate the growth of probiotic bacteria. Genomes of probiotic lactobacilli from the acidophilus group, as represented by Lactobacillus acidophilus NCFM, encode ␣-1,6 glucosidases of the family GH13_31 (glycoside hydrolase family 13 subfamily 31) that confer degradation of IMO. These genes reside frequently within maltooligosaccharide utilization operons, which include an ATP-binding cassette transporter and ␣-glucan active enzymes, e.g., maltogenic amylases and maltose phosphorylases, and they also occur separated from any carbohydrate transport or catabolism genes on the genomes of some acidophilus complex members, as in L. acidophilus NCFM. Besides the isolated locus encoding a GH13_31 enzyme, the ABC transporter and another GH13 in the maltooligosaccharide operon were induced in response to IMO or maltotetraose, as determined by reverse transcription-PCR (RT-PCR) transcriptional analysis, suggesting coregulation of ␣-1,6-and ␣-1,4-glucooligosaccharide utilization loci in L. acidophilus NCFM. The L. acidophilus NCFM GH13_31 (LaGH13_31) was produced recombinantly and shown to be a glucan 1,6-␣-glucosidase active on IMO and dextran and product-inhibited by glucose. The catalytic efficiency of LaGH13_31 on dextran and the dextran/panose (trisaccharide) efficiency ratio were the highest reported for this class of enzymes, suggesting higher affinity at distal substrate binding sites. The crystal structure of LaGH13_31 was determined to a resolution of 2.05 Å and revealed additional substrate contacts at the ؉2 subsite in LaGH13_31 compared to the GH13_31 from Streptococcus mutans (SmGH13_31), providing a possible structural rationale to the relatively high affinity for dextran. A comprehensive phylogenetic and activity motif analysis mapped IMO utilization enzymes from gut microbiota to rationalize preferential utilization of IMO by gut residents.

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Section: Figmentioning

confidence: 82%

Section: Figmentioning

confidence: 99%

mentioning

confidence: 99%

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Enzymology and Structure of the GH13_31 Glucan 1,6-α-Glucosidase That Confers Isomaltooligosaccharide Utilization in the Probiotic Lactobacillus acidophilus NCFM

et al. 2012

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“…The enzyme activity significantly decreased upon substitution of Asp-194 to Ala, and its specific activity was 6.70 ϫ 10 Ϫ4 units/mg (3.9 ϫ 10 Ϫ4 % of wild type). This indicates that as the catalytic nucleophile, Asp-194 is essential for enzyme activity as predicted from the structural analysis of SmDG (12) and comparison of its amino acid sequence with those GH 13 enzymes where the catalytic nucleophiles have been demonstrated experimentally (24 -28) ( Table 2).…”

Section: Resultsmentioning

confidence: 77%

Replacement of the Catalytic Nucleophile Aspartyl Residue of Dextran Glucosidase by Cysteine Sulfinate Enhances Transglycosylation Activity

Saburi

Kobayashi

Mori

et al. 2013

Journal of Biological Chemistry

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Dextran glucosidase from Streptococcus mutans (SmDG) catalyzes the hydrolysis of an α-1,6-glucosidic linkage at the nonreducing end of isomaltooligosaccharides and dextran. This enzyme has an Asp-194 catalytic nucleophile and two catalytically unrelated Cys residues, Cys-129 and Cys-532. Cys-free SmDG was constructed by replacement with Ser (C129S/C532S (2CS), the activity of which was the same as that of the wild type, SmDG). The nucleophile mutant of 2CS was generated by substitution of Asp-194 with Cys (D194C-2CS). The hydrolytic activity of D194C-2CS was 8.1 × 10⁻⁴ % of 2CS. KI-associated oxidation of D194C-2CS increased the activity up to 0.27% of 2CS, which was 330 times higher than D194C-2CS. Peptide-mapping mass analysis of the oxidized D194C-2CS (Ox-D194C-2CS) revealed that Cys-194 was converted into cysteine sulfinate. Ox-D194C-2CS and 2CS shared the same properties (optimum pH, pI, and substrate specificity), whereas Ox-D194C-2CS had much higher transglucosylation activity than 2CS. This is the first study indicating that a more acidic nucleophile (-SOO−) enhances transglycosylation. The introduction of cysteine sulfinate as a catalytic nucleophile could be a novel approach to enhance transglycosylation

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“…GH 13 ␣-glucosidases (13AGs) (1,(3)(4)(5)(6)(7) have four conserved regions of ␣-amylase family enzymes (8). Their three-dimensional structures have been resolved (3,5). The catalytic domains form a (␤/␣) 8 -barrel.…”

mentioning

confidence: 99%

A Novel Metabolic Pathway for Glucose Production Mediated by α-Glucosidase-catalyzed Conversion of 1,5-Anhydrofructose

Kim

Saburi

Yu³

et al. 2012

Journal of Biological Chemistry

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Background: ␣-Glucosidase-catalyzed hydration on 1,5-anhydrofructose has not been clarified. Results: ␣-Glucosidases of glycoside hydrolase families 13 and 31 synthesize ␣-configurated product from 1,5-anhydrofructose. Combined reaction of glucan lyase and ␣-glucosidase enhances glucose production from starch. Conclusion: ␣-Glucosidases catalyze trans-addition on 1,5-anhydrofructose. Significance: Novel ␣-glucosidase-associated metabolic pathway of glucose formation from 1,5-anhydrofructose suggests a salvage process of unutilized 1,5-anhydrofructose to glucose in nature.

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Substrate Recognition Mechanism of α-1,6-Glucosidic Linkage Hydrolyzing Enzyme, Dextran Glucosidase from Streptococcus mutans

Cited by 63 publications

References 44 publications

Enzymology and Structure of the GH13_31 Glucan 1,6-α-Glucosidase That Confers Isomaltooligosaccharide Utilization in the Probiotic Lactobacillus acidophilus NCFM

Enzymology and Structure of the GH13_31 Glucan 1,6-α-Glucosidase That Confers Isomaltooligosaccharide Utilization in the Probiotic Lactobacillus acidophilus NCFM

Replacement of the Catalytic Nucleophile Aspartyl Residue of Dextran Glucosidase by Cysteine Sulfinate Enhances Transglycosylation Activity

A Novel Metabolic Pathway for Glucose Production Mediated by α-Glucosidase-catalyzed Conversion of 1,5-Anhydrofructose

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