{"doi":"10.1101/2020.05.26.111013","title":"PelX is a UDP- <i>N</i> -acetylglucosamine C4-epimerase involved in Pel polysaccharide-dependent biofilm formation","abstract":"ABSTRACT Pel is an N -acetylgalactosamine rich polysaccharide that contributes to the structure and function of Pseudomonas aeruginosa biofilms. The pelABCDEFG operon is highly conserved among diverse bacterial species, and thus Pel may be a widespread biofilm determinant. Previous annotation of pel gene clusters led us to identify an additional gene, pelX , that is found adjacent to pelABCDEFG in over 100 different bacterial species. The pelX gene is predicted to encode a member of the short-chain dehydrogenase/reductase (SDR) superfamily of enzymes, but its potential role in Pel-dependent biofilm formation is unknown. Herein, we have used Pseudomonas protegens Pf-5 as a model to understand PelX function as P. aeruginosa lacks a pelX homologue in its pel gene cluster. We find that P. protegens forms Pel-dependent biofilms, however, despite expression of pelX under these conditions, biofilm formation was unaffected in a Δ pelX strain. This observation led to our identification of the pelX paralogue, PFL_5533, which we designate pgnE , that appears to be functionally redundant to pelX . In line with this, a Δ pelX Δ pgnE 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 2.1Å resolution. The structure revealed that PelX resembles UDP- N -acetylglucosamine (UDP-GlcNAc) C4-epimerases and, using 1 H NMR analysis, we show that PelX catalyzes the epimerization between UDP-GlcNAc and UDP-GalNAc. Taken together, our results demonstrate 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.","journal":"bioRxiv (Cold Spring Harbor Laboratory)","year":2020,"id":129927,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":0,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9535,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2020-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":347999,"name":"Gregory B. Whitfield","orcid":"0000-0003-0274-8402","position":1,"is_corresponding":false},{"id":581732,"name":"Roland Pfoh","orcid":"0000-0003-2283-3604","position":2,"is_corresponding":false},{"id":582158,"name":"R.J. Williams","orcid":null,"position":3,"is_corresponding":false},{"id":289123,"name":"Trevor E. Randall","orcid":"0000-0003-4402-9457","position":4,"is_corresponding":false},{"id":582159,"name":"Alexandra Ostaszewski","orcid":null,"position":5,"is_corresponding":false},{"id":581733,"name":"Erum Razvi","orcid":"0000-0002-5555-1438","position":6,"is_corresponding":false},{"id":581734,"name":"Ryan A. Groves","orcid":"0000-0002-9737-5161","position":7,"is_corresponding":false},{"id":519448,"name":"Howard Robinson","orcid":"0000-0001-7523-4678","position":8,"is_corresponding":false},{"id":581735,"name":"Mark Nitz","orcid":"0000-0001-8078-2265","position":9,"is_corresponding":false},{"id":288483,"name":"Matthew R. Parsek","orcid":"0000-0003-2932-7966","position":10,"is_corresponding":false},{"id":581736,"name":"Ian A. Lewis","orcid":"0000-0002-5753-499X","position":11,"is_corresponding":false},{"id":348001,"name":"John C. Whitney","orcid":"0000-0002-4517-8836","position":12,"is_corresponding":false},{"id":289118,"name":"Joe J. Harrison","orcid":"0000-0003-0368-9539","position":13,"is_corresponding":false},{"id":348002,"name":"P. Lynne Howell","orcid":"0000-0002-2776-062X","position":14,"is_corresponding":false},{"id":348000,"name":"Lindsey S. Marmont","orcid":"0000-0002-4225-2690","position":0,"is_corresponding":true}],"reference_count":57,"raw_metadata":null,"created_at":"2026-07-18T23:15:49.682497Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}