{"doi":"10.1016/j.jbc.2023.105578","title":"Molecular mechanisms underlying the structural diversity of rhamnose-rich cell wall polysaccharides in lactococci","abstract":"In Gram-positive bacteria, cell wall polysaccharides (CWPS) play critical roles in bacterial cell wall homeostasis and bacterial interactions with their immediate surroundings. In lactococci, CWPS consist of two components: a conserved rhamnan embedded in the peptidoglycan layer and a surface-exposed polysaccharide pellicle (PSP), which are linked together to form a large rhamnose-rich CWPS (Rha-CWPS). PSP, whose structure varies from strain to strain, is a receptor for many bacteriophages infecting lactococci. Here, we examined the first two steps of PSP biosynthesis, using in vitro enzymatic tests with lipid acceptor substrates combined with LC-MS analysis, AlfaFold2 modeling of protein 3D-structure, complementation experiments, and phage assays. We show that the PSP repeat unit is assembled on an undecaprenyl-monophosphate (C 55 P) lipid intermediate. Synthesis is initiated by the WpsA/WpsB complex with GlcNAc-P-C 55 synthase activity and the PSP precursor GlcNAc-P-C 55 is then elongated by specific glycosyltransferases that vary among lactococcal strains, resulting in PSPs with diverse structures. Also, we engineered the PSP biosynthesis pathway in lactococci to obtain a chimeric PSP structure, confirming the predicted glycosyltransferase specificities. This enabled us to highlight the importance of a single sugar residue of the PSP repeat unit in phage recognition. In conclusion, our results support a novel pathway for PSP biosynthesis on a lipid-monophosphate intermediate as an extracellular modification of rhamnan, unveiling an assembly machinery for complex Rha-CWPS with structural diversity in lactococci.","journal":"Journal of Biological Chemistry","year":2023,"id":376244,"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":4,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9562,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2023-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":1139038,"name":"Pascal Courtin","orcid":"0000-0001-8731-8318","position":1,"is_corresponding":false},{"id":1139490,"name":"Alain Guillot","orcid":null,"position":2,"is_corresponding":false},{"id":1139039,"name":"Christine Péchoux","orcid":"0000-0002-5885-2762","position":3,"is_corresponding":false},{"id":901807,"name":"Jennifer Mahony","orcid":"0000-0001-5846-6303","position":4,"is_corresponding":false},{"id":901806,"name":"Douwe van Sinderen","orcid":"0000-0003-1823-7957","position":5,"is_corresponding":false},{"id":1139040,"name":"Saulius Kulakauskas","orcid":"0000-0002-3466-8266","position":6,"is_corresponding":false},{"id":705143,"name":"Christian Cambillau","orcid":"0000-0001-5502-4729","position":7,"is_corresponding":false},{"id":1139041,"name":"Thierry Touzé","orcid":"0000-0002-2176-6537","position":8,"is_corresponding":false},{"id":1139042,"name":"Marie‐Pierre Chapot‐Chartier","orcid":"0000-0002-4947-0519","position":9,"is_corresponding":false},{"id":1139489,"name":"H. Guérin","orcid":null,"position":0,"is_corresponding":true}],"reference_count":52,"raw_metadata":null,"created_at":"2026-07-19T01:16:28.318749Z","pmid":"38110036","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":[]}