PDBsum entry 4azh

Hydrolase

PDB id: 4azh

Contents

Protein chains

421 a.a.

Ligands

LOG ×4

EDO ×12

Waters ×1293

PDB id:

4azh

Name:

Hydrolase

Title:

Differential inhibition of the tandem gh20 catalytic modules in the pneumococcal exo-beta-d-n-acetylglucosaminidase, strh

Structure:

Beta-n-acetylhexosaminidase. Chain: a, b, c, d. Fragment: catalytic module, residues 627-1064. Synonym: glycoside hydrolase 20. Engineered: yes

Source:

Streptococcus pneumoniae. Organism_taxid: 170187. Strain: tigr4. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

2.22Å R-factor: 0.200 R-free: 0.259

Authors:

B.Pluvinage,K.A.Stubbs,D.J.Vocadlo,A.B.Boraston

Key ref:

B.Pluvinage et al. (2013). Inhibition of the family 20 glycoside hydrolase catalytic modules in the Streptococcus pneumoniae exo-β-D-N-acetylglucosaminidase, StrH. Org Biomol Chem, 11, 7907-7915. PubMed id: 24132305 DOI: 10.1039/c3ob41579a

Date:

26-Jun-12 Release date: 10-Jul-13

Protein chains

P49610  (STRH_STRPN) -  Beta-N-acetylhexosaminidase from Streptococcus pneumoniae serotype 4 (strain ATCC BAA-334 / TIGR4)

Seq: 1312 a.a.

Struc: 421 a.a.*

* PDB and UniProt seqs differ at 4 residue positions (black crosses)

Enzyme reactions

• Enzyme class: E.C.3.2.1.52 - beta-N-acetylhexosaminidase.
• Reaction: Hydrolysis of terminal non-reducing N-acetyl-D-hexosamine residues in N-acetyl-beta-D-hexosaminides.

DOI no: 10.1039/c3ob41579a

Org Biomol Chem 11:7907-7915 (2013)

PubMed id: 24132305

Inhibition of the family 20 glycoside hydrolase catalytic modules in the Streptococcus pneumoniae exo-β-D-N-acetylglucosaminidase, StrH.

B.Pluvinage, K.A.Stubbs, M.Hattie, D.J.Vocadlo, A.B.Boraston.

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.