6R5I

The crystal structure of the Glycoside Hydrolase BglX from P. aeruginosa

Summary for 6R5I

• Entry DOI: 10.2210/pdb6r5i/pdb
• Descriptor: Periplasmic beta-glucosidase, SULFATE ION, MAGNESIUM ION, ... (4 entities in total)
• Functional Keywords: glycoside hydrolase, hydrolase
• Biological source: Pseudomonas aeruginosa (strain ATCC 15692 / DSM 22644 / CIP 104116 / JCM 14847 / LMG 12228 / 1C / PRS 101 / PAO1)
• Total number of polymer chains: 2
• Total formula weight: 160648.58

Authors

Batuecas, M.T.,Hermoso, J.A. (deposition date: 2019-03-25, release date: 2020-04-15, Last modification date: 2024-01-24)

Primary citation

Mahasenan, K.V.,Batuecas, M.T.,De Benedetti, S.,Kim, C.,Rana, N.,Lee, M.,Hesek, D.,Fisher, J.F.,Sanz-Aparicio, J.,Hermoso, J.A.,Mobashery, S.
Catalytic Cycle of Glycoside Hydrolase BglX fromPseudomonas aeruginosaand Its Implications for Biofilm Formation.
Acs Chem.Biol., 15:189-196, 2020

PubMed Abstract: BglX is a heretofore uncharacterized periplasmic glycoside hydrolase (GH) of the human pathogen . X-ray analysis identifies it as a protein homodimer. The two active sites of the homodimer comprise catalytic residues provided by each monomer. This arrangement is seen in <2% of the hydrolases of known structure. substrate profiling shows BglX is a catalyst for β-(1→2) and β-(1→3) saccharide hydrolysis. Saccharides with β-(1→4) or β-(1→6) bonds, and the β-(1→4) muropeptides from the cell-wall peptidoglycan, are not substrates. Additional structural insights from X-ray analysis (including structures of a mutant enzyme-derived Michaelis complex, two transition-state mimetics, and two enzyme-product complexes) enabled the comprehensive description of BglX catalysis. The half-chair () conformation of the transition-state oxocarbenium species, the approach of the hydrolytic water molecule to the oxocarbenium species, and the stepwise release of the two reaction products were also visualized. The substrate pattern for BglX aligns with the [β-(1→2)-Glc] and [β-(1→3)-Glc] periplasmic osmoregulated periplasmic glucans, and possibly with the Psl exopolysaccharides, of . Both polysaccharides are implicated in biofilm formation. Accordingly, we show that inactivation of the gene of PAO1 attenuates biofilm formation.

PubMed: 31877028
DOI: 10.1021/acschembio.9b00754

Experimental method

X-RAY DIFFRACTION (1.8 Å)