title: The Ser/Thr/Tyr phosphoproteome of Lactococcus lactis IL1403 reveals multiply phosphorylated proteins.
abstract: Recent phosphoproteomics studies of several bacterial species have firmly established protein phosphorylation on Ser/Thr/Tyr residues as a PTM in bacteria. In particular, our recent reports on the Ser/Thr/Tyr phosphoproteomes of bacterial model organisms Bacillus subtilis and Escherichia coli detected over 100 phosphorylation events in each of the bacterial species. Here we extend our analyses to Lactococcus lactis, a lactic acid bacterium widely employed by the food industry, in which protein phosphorylation at Ser/Thr/Tyr residues was barely studied at all. Despite the lack of almost any prior evidence of Ser/Thr/Tyr protein phosphorylation in L. lactis, we identified a phosphoproteome of a size comparable to that of E. coli and B. subtilis, with 73 phosphorylation sites distributed over 63 different proteins. The presence of several multiply phosphorylated proteins, as well as over-representation of phosphothreonines seems to be the distinguishing features of the L. lactis phosphoproteome. Evolutionary comparison and the conservation of phosphorylation sites in different bacterial organisms indicate that a majority of the detected phosphorylation sites are species-specific, and therefore have probably co-evolved with the adaptation of the bacterial species to their present-day ecological niches.
authors.affiliation: Center for Microbial Biotechnology, BioCentrum, Technical University of Denmark, Lyngby, Denmark.
authors.forename: Boumediene
authors.initials: B
authors.lastname: Soufi
authors.forename: Florian
authors.initials: F
authors.lastname: Gnad
authors.forename: Peter Ruhdal
authors.initials: PR
authors.lastname: Jensen
authors.forename: Dina
authors.initials: D
authors.lastname: Petranovic
authors.forename: Matthias
authors.initials: M
authors.lastname: Mann
authors.forename: Ivan
authors.initials: I
authors.lastname: Mijakovic
authors.forename: Boris
authors.initials: B
authors.lastname: Macek
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000032:analysis*; D006019:Glycolysis; D013294:Lactococcus lactis / Q000378:metabolism*; D010748:Phosphopeptides / Q000378:metabolism*; D010766:Phosphorylation; D020543:Proteome / Q000032:analysis*; D012694:Serine / Q000378:metabolism; D053719:Tandem Mass Spectrometry; D013912:Threonine / Q000378:metabolism; D014443:Tyrosine / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D010748:Phosphopeptides; D020543:Proteome; D013912:Threonine; D014443:Tyrosine; D012694:Serine