{"doi":"10.1101/2020.05.20.106443","title":"Resistance to serine in <i>Bacillus subtilis</i> : Identification of the serine transporter YbeC and of a metabolic network that links serine and threonine metabolism","abstract":"Summary The Gram-positive bacterium Bacillus subtilis uses serine not only as building block for proteins but also as an important precursor in many anabolic reactions. Moreover, a lack of serine results in the initiation of biofilm formation. However, in excess serine inhibits the growth of B. subtilis . To unravel the underlying mechanisms, we isolated suppressor mutants that can tolerate toxic serine concentrations by three targeted and non-targeted genome-wide screens. All screens as well as genetic complementation in Escherichia coli identified the so far uncharacterized permease YbeC as the major serine transporter of B. subtilis . In addition to YbeC, the threonine transporters BcaP and YbxG make minor contributions to serine uptake. A strain lacking these three transporters was able to tolerate 100 mM serine whereas the wild type strain was already inhibited by 1 mM of the amino acid. The screen for serine-resistant mutants also identified mutations that result in increased serine degradation and in increased expression of threonine biosynthetic enzymes suggesting that serine toxicity results from interference with threonine biosynthesis. Originality-Significance Statement Serine is an important precursor for many biosynthetic reactions, and lack of this amino acid can induce biofilm formation in Bacillus subtilis . However, serine is toxic for the growth of B. subtilis . To understand the reason(s) for this toxicity and to identify the so far unknown serine transporter(s) of this bacterium, we performed exhaustive mutant screens to isolate serine-resistant mutants. This screen identified YbeC, the major serine transporter of B. subtilis . Moreover, we observed an intimate link between serine and threonine metabolism that is responsible for serine toxicity by inhibiting threonine biosynthesis.","journal":"bioRxiv (Cold Spring Harbor Laboratory)","year":2020,"id":126718,"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":1,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9568,"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":259591,"name":"Byoung‐Mo Koo","orcid":"0000-0003-1001-6367","position":1,"is_corresponding":false},{"id":574606,"name":"Larissa Krüger","orcid":"0000-0003-2053-4010","position":2,"is_corresponding":false},{"id":574607,"name":"Anja Poehlein","orcid":"0000-0002-2473-6202","position":3,"is_corresponding":false},{"id":575227,"name":"Daniel R. Reuß","orcid":null,"position":4,"is_corresponding":false},{"id":574608,"name":"Rolf Daniel","orcid":"0000-0002-8646-7925","position":5,"is_corresponding":false},{"id":259595,"name":"Carol A. Gross","orcid":"0000-0002-5595-9732","position":6,"is_corresponding":false},{"id":332637,"name":"Jörg Stülke","orcid":"0000-0001-5881-5390","position":7,"is_corresponding":false},{"id":575226,"name":"Anika Klewing","orcid":null,"position":0,"is_corresponding":true}],"reference_count":54,"raw_metadata":null,"created_at":"2026-07-18T23:15:27.226519Z","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":[]}