Structure of N-acetyl-β-D-glucosaminidase (GcnA) from the Endocarditis Pathogen Streptococcus gordonii and its Complex with the Mechanism-based Inhibitor NAG-thiazoline

Langley, David B.; Harty, D. W. S.; Jacques, Nicholas A.; Hunter, Neil; Guss, J. Mitchell; Collyer, Charles A.

doi:10.1016/j.jmb.2007.09.028

Cited by 39 publications

(35 citation statements)

References 31 publications

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“…Domain III is all ␣-helical with four anti-parallel helices organized in a near planar arrangement. Domain III is unusual among structurally characterized GH20 enzymes and has only been observed in GcnA (30,43). Indeed, GH20C and GcnA share the same domain organization and an overall root mean square deviation of 0.79 Å over 619 matched C␣s.…”

Section: Volume 290 • Number 52 • December 25 2015mentioning

confidence: 99%

“…This gene appears to be present in all sequenced strains of the bacterium. The putative product of this gene, referred to as GH20C, displays ϳ70% amino acid sequence identity with the structurally characterized Streptococcus gordonii GcnA, which displays both N-acetylgalactosaminidase and N-acetylglucosaminidase activity on synthetic aryl glycosides (29,30). Although the relatively high amino acid sequence identity between GcnA and GH20C lends itself to inferring similar abilities to cleave N-acetylhexosaminides, GH20C remains uncharacterized.…”

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confidence: 99%

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A Second β-Hexosaminidase Encoded in the Streptococcus pneumoniae Genome Provides an Expanded Biochemical Ability to Degrade Host Glycans

Robb

Higgins

et al. 2015

Journal of Biological Chemistry

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Section: Volume 290 • Number 52 • December 25 2015mentioning

confidence: 99%

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confidence: 99%

A Second β-Hexosaminidase Encoded in the Streptococcus pneumoniae Genome Provides an Expanded Biochemical Ability to Degrade Host Glycans

Robb

Higgins

et al. 2015

Journal of Biological Chemistry

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“…We also resolved the crystal structures of free OfHex1 and OfHex1 in complex with the recently isolated inhibitor TMGchitotriomycin to 2.1 Å. Structural alignment of OfHex1 with reported ␤-N-acetyl-D-hexosaminidases from humans (14 -16) and bacteria (17)(18)(19)(20)(21)(22)(23) revealed several unique structural features in OfHex1, which provided further insight into the structural basis of the enzyme's specialized function. Because O. furnacalis is a destructive and persistent pest in the Asian and pan-Pacific regions, a greater understanding of the structure-function relationship of OfHex1 would enable the development of a more species-specific pesticide.…”

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confidence: 92%

“…TS12, PsHex, that can efficiently degrade various glycosphingolipids (22). In addition, PgGcnA, the enzyme found in the endocarditis pathogen, Streptococcus gordonii, is involved in the release of dietary carbohydrates (23). To our knowledge, no crystal structure of insect ␤-N-acetyl-D-hexosaminidase has yet been reported.…”

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confidence: 99%

Structural Determinants of an Insect β-N-Acetyl-d-hexosaminidase Specialized as a Chitinolytic Enzyme

Liu

Zhang

Liu

et al. 2011

Journal of Biological Chemistry

119

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␤-N-Acetyl-D-hexosaminidase has been postulated to have a specialized function. However, the structural basis of this specialization is not yet established. OfHex1, the enzyme from the Asian corn borer Ostrinia furnacalis (one of the most destructive pests) has previously been reported to function merely in chitin degradation. Here the vital role of OfHex1 during the pupation of O. furnacalis was revealed by RNA interference, and the crystal structures of OfHex1 and OfHex1 complexed with TMG-chitotriomycin were determined at 2.1 Å . The mechanism of selective inhibition by TMG-chitotriomycin was related to the existence of the ؉1 subsite at the active pocket of OfHex1 and a key residue, Trp 490 , at this site. Mutation of Trp 490 to Ala led to a 2,277-fold decrease in sensitivity toward TMG-chitotriomycin as well as an 18-fold decrease in binding affinity for the substrate (GlcNAc) 2 . Although the overall topology of the catalytic domain of OfHex1 shows a high similarity with the human and bacterial enzymes, OfHex1 is distinguished from these enzymes by large conformational changes linked to an "open-close" mechanism at the entrance of the active site, which is characterized by the "lid" residue, Trp 448 . Mutation of Trp 448 to Ala or Phe resulted in a more than 1,000-fold loss in enzyme activity, due mainly to the effect on k cat . The current work has increased our understanding of the structure-function relationship of OfHex1, shedding light on the structural basis that accounts for the specialized function of ␤-N-acetyl-D-hexosaminidase as well as making the development of species-specific pesticides a likely reality.␤-N-Acetyl-D-hexosaminidase (EC 3.2.1.52), a member of the family 20 glycosyl hydrolyases (GH20), 4 is an enzyme that participates in the breakdown of glycosidic bonds of glycans, glycoproteins, and glycolipids (1). It has been postulated to have specialized physiological functions, including post-translational modification of N-glycans, degradation of glycoconjugates, and egg-sperm recognition (1). The structural basis for these specialized functions is still unclear.It is interesting to note that insects have evolved to have more than one ␤-N-acetyl-D-hexosaminidase, as revealed by genomic analysis of various insects, including Coleoptera, Diptera, Hymenoptera, Lepidoptera, Phthiraptera, and Hemiptera. The activities of insect ␤-N-acetyl-D-hexosaminidases are not restricted to chitin degradation but are also associated with post-translational modification of N-glycans, degradation of glycoconjugates, and egg-sperm recognition, suggesting that these enzymes have rather versatile physiological functions in the growth and development of insects (2). Some of these physiological functions may overlap with those of the same enzymes found in higher organisms. Mammal lysosomal ␤-N-acetyl-D-hexosaminidases are mainly responsible for glycoconjugate degradation in lysosome (3). Likewise, ␤-N-acetyl-D-hexosaminidases from the insects Bombyx mori (4) and Spodoptera frugiperda (5) have broad substrate spe...

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“…Thus, SGO_0150, which occurs as an isolated gene in S. gordonii DL1, may act on Fuc␣1-2Gal that is cleaved from PRG by the action of BgaA. Moreover, SGO_1771, which occurs in the previously described gom regulon (35) along with genes for a structurally characterized N-acetylglucosaminidase (36) and three putative mannosidases, may function in the metabolism of larger, Man-containing branched oligosaccharides that result from the action of EndoD. Indeed, inactivation of certain genes in the gom locus was found to reduce the growth of S. gordonii on both ␣1-6-D-mannobiose and GlcNAc␤1-2Man (35).…”

Section: Discussionmentioning

confidence: 89%

Cell Surface Glycoside Hydrolases of Streptococcus gordonii Promote Growth in Saliva

Yang

Zhou

Zhang

et al. 2016

Appl Environ Microbiol

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The growth of the oral commensal Streptococcus gordonii in saliva may depend on a number of glycoside hydrolases (GHs), including three cell wall-anchored proteins that are homologs of pneumococcal ␤-galactosidase (BgaA), ␤-N-acetylglucosaminidase (StrH), and endo-␤-N-acetylglucosaminidase D (EndoD). In the present study, we introduced unmarked in-frame deletions into the corresponding genes of S. gordonii DL1, verified the presence (or absence) of the encoded proteins on the resulting mutant strains, and compared these strains with wild-type strain DL1 for growth and glycan foraging in saliva. The overnight growth of wild-type DL1 was reduced 3-to 10-fold by the deletion of any one or two genes and approximately 20-fold by the deletion of all three genes. The only notable change in the salivary proteome associated with this reduction of growth was a downward shift in the apparent molecular masses of basic proline-rich glycoproteins (PRG), which was accompanied by the loss of lectin binding sites for galactose-specific Erythrina cristagalli agglutinin (ECA) and mannose-specific Galanthus nivalis agglutinin (GNA). The binding of ECA to PRG was also abolished in saliva cultures of mutants that expressed cell surface BgaA alone or together with either StrH or EndoD. However, the subsequent loss of GNA binding was seen only in saliva cocultures of different mutants that together expressed all three cell surface GHs. The findings indicate that the growth of S. gordonii DL1 in saliva depends to a significant extent on the sequential actions of first BgaA and then StrH and EndoD on N-linked glycans of PRG. IMPORTANCEThe ability of oral bacteria to grow on salivary glycoproteins is critical for dental plaque biofilm development. Little is known, however, about how specific salivary components are attacked and utilized by different members of the biofilm community, such as Streptococcus gordonii. Streptococcus gordonii DL1 has three cell wall-anchored glycoside hydrolases that are predicted to act on host glycans. In the present study, we introduced unmarked in-frame deletions in the corresponding genes, verified the presence (or absence) of encoded proteins on the resulting mutant strains, and compared these strains with wild-type DL1 for growth and glycan foraging in saliva. The results indicate that the growth of S. gordonii DL1 depends to a significant extent on sequential action of these cell surface GHs on N-linked glycans of basic proline-rich salivary glycoproteins, which appears to be an essential first step in salivary glycan foraging. T he development of dental plaque in the absence of exogenous nutrients has long been thought to depend on bacterial foraging of host salivary glycans (1, 2). Little is known, however, about how different oral species attack and utilize salivary macromolecules as substrates for growth and whether cross-feeding between species influences dental plaque biofilm development. Recently, we compared the growth of different oral bacteria in filter-sterilized saliva that was first...

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Structure of N-acetyl-β-D-glucosaminidase (GcnA) from the Endocarditis Pathogen Streptococcus gordonii and its Complex with the Mechanism-based Inhibitor NAG-thiazoline

Cited by 39 publications

References 31 publications

A Second β-Hexosaminidase Encoded in the Streptococcus pneumoniae Genome Provides an Expanded Biochemical Ability to Degrade Host Glycans

A Second β-Hexosaminidase Encoded in the Streptococcus pneumoniae Genome Provides an Expanded Biochemical Ability to Degrade Host Glycans

Structural Determinants of an Insect β-N-Acetyl-d-hexosaminidase Specialized as a Chitinolytic Enzyme

Cell Surface Glycoside Hydrolases of Streptococcus gordonii Promote Growth in Saliva

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