4AZ5

Differential inhibition of the tandem GH20 catalytic modules in the pneumococcal exo-beta-D-N-acetylglucosaminidase, StrH

Summary for 4AZ5

• Entry DOI: 10.2210/pdb4az5/pdb
• Related: 2YL5 2YL6 2YL8 2YL9 2YLA 2YLL 4AZ6 4AZ7
• Descriptor: BETA-N-ACETYLHEXOSAMINIDASE, (2S,3aR,5R,6S,7R,7aR)-5-(hydroxymethyl)-2-methyl-2,3a,5,6,7,7a-hexahydro-1H-pyrano[3,2-d][1,3]thiazole-6,7-diol, MAGNESIUM ION, ... (6 entities in total)
• Functional Keywords: hydrolase
• Biological source: STREPTOCOCCUS PNEUMONIAE
• Cellular location: Secreted, cell wall ; Peptidoglycan-anchor : P49610
• Total number of polymer chains: 1
• Total formula weight: 49066.88

Authors

Pluvinage, B.,Stubbs, K.A.,Vocadlo, D.J.,Boraston, A.B. (deposition date: 2012-06-22, release date: 2013-07-10, Last modification date: 2023-12-20)

Primary citation

Pluvinage, B.,Stubbs, K.A.,Vocadlo, D.J.,Boraston, A.B.
Inhibition of the Family 20 Glycoside Hydrolase Catalytic Modules in the Streptococcus Pneumoniae Exo-Beta-D-N-Acetylglucosaminidase, Strh.
Org.Biomol.Chem., 11:7907-, 2013

PubMed Abstract: Streptococcus pneumoniae produces a cell-surface attached β-N-acetylglucosaminidase called StrH that is used by this pathogen to process the termini of host complex N-linked glycans. N-Acetyl-D-glucosamine-thiazoline (NAG-Thiazoline, NGT) and O-(2-acetamido-2-deoxy-D-glucopyranosylidene)amino N-phenyl carbamate (PUGNAc) are inhibitors of the two family 20 glycoside hydrolase catalytic modules within StrH and these inhibitors have proven useful in modulating the activity of StrH in assays that model aspects of the host-bacterium interaction. Here we explore the molecular basis of StrH inhibition through structural, kinetic, thermodynamic and site-directed mutagenic analyses using the recombinantly produced independent catalytic modules of StrH (GH20A and GH20B) and the inhibitors NGT and PUGNAc. The results reveal a similar binding mode of the sugar moiety of these inhibitors at the -1 subsite in the active sites of GH20A and GH20B. The lower affinity of NGT as compared to PUGNAc for these catalytic modules can be attributed to the hydrophobic phenylcarbamate moiety of PUGNAc that is absent in NGT. This moiety also displayed variations in its interactions with the active sites of GH20A and GH20B that provide a rationale for the 400-fold difference observed in the Ki values of this compound for these two β-N-acetylglucosaminidase catalytic modules.

PubMed: 24132305
DOI: 10.1039/C3OB41579A

Experimental method

X-RAY DIFFRACTION (1.73 Å)