6WJA

UDP-GlcNAc C4-epimerase mutant S121A/Y146F from Pseudomonas protegens in complex with UDP-GalNAc

Summary for 6WJA

• Entry DOI: 10.2210/pdb6wja/pdb
• Descriptor: NAD-dependent epimerase/dehydratase family protein, NICOTINAMIDE-ADENINE-DINUCLEOTIDE, URIDINE-DIPHOSPHATE-N-ACETYLGALACTOSAMINE, ... (4 entities in total)
• Functional Keywords: short chain dehydrogenase, isomerase, complex, nad dependent
• Biological source: Pseudomonas protegens
• Total number of polymer chains: 2
• Total formula weight: 67815.31

Authors

Marmont, L.S.,Pfoh, R.,Howell, P.L. (deposition date: 2020-04-13, release date: 2020-07-08, Last modification date: 2023-10-18)

Primary citation

Marmont, L.S.,Whitfield, G.B.,Pfoh, R.,Williams, R.J.,Randall, T.E.,Ostaszewski, A.,Razvi, E.,Groves, R.A.,Robinson, H.,Nitz, M.,Parsek, M.R.,Lewis, I.A.,Whitney, J.C.,Harrison, J.J.,Howell, P.L.
PelX is a UDP-N-acetylglucosamine C4-epimerase involved in Pel polysaccharide-dependent biofilm formation.
J.Biol.Chem., 295:11949-11962, 2020

PubMed Abstract: Pel is a GalNAc-rich bacterial polysaccharide that contributes to the structure and function of biofilms. The operon is highly conserved among diverse bacterial species, and Pel may therefore be a widespread biofilm determinant. Previous annotation of gene clusters has helped us identify an additional gene, , that is present adjacent to in >100 different bacterial species. The gene is predicted to encode a member of the short-chain dehydrogenase/reductase (SDR) superfamily, but its potential role in Pel-dependent biofilm formation is unknown. Herein, we have used Pf-5 as a model to elucidate PelX function as lacks a homologue in its gene cluster. We found that forms Pel-dependent biofilms; however, despite expression of under these conditions, biofilm formation was unaffected in a Δ strain. This observation led us to identify a paralogue, PFL_5533, which we designate here PgnE, that appears to be functionally redundant to In line with this, a Δ Δ double mutant was substantially impaired in its ability to form Pel-dependent biofilms. To understand the molecular basis for this observation, we determined the structure of PelX to 2.1 Å resolution. The structure revealed that PelX resembles UDP-GlcNAc C4-epimerases. Using H NMR analysis, we show that PelX catalyzes the epimerization between UDP-GlcNAc and UDP-GalNAc. Our results indicate that Pel-dependent biofilm formation requires a UDP-GlcNAc C4-epimerase that generates the UDP-GalNAc precursors required by the Pel synthase machinery for polymer production.

PubMed: 32601062
DOI: 10.1074/jbc.RA120.014555

Experimental method

X-RAY DIFFRACTION (2.094 Å)