title: Structural basis of flocculin-mediated social behavior in yeast.
abstract: In the budding yeast Saccharomyces cerevisiae, self-recognition and the thereby promoted aggregation of thousands of cells into protective flocs is mediated by a family of cell-surface adhesins, the flocculins (Flo). Based on this social behavior FLO genes fulfill the definition of "greenbeard" genes, which direct cooperation toward other carriers of the same gene. The process of flocculation plays an eminent role in the food industry for the production of beer and wine. However, the precise mode of flocculin-mediated surface recognition and the exact structure of cognate ligands have remained elusive. Here, we present structures of the adhesion domain of a flocculin complexed to its cognate ligands derived from yeast high-mannose oligosaccharides at resolutions up to 0.95 Å. Besides a PA14-like architecture, the Flo5A domain reveals a previously undescribed lectin fold that utilizes a unique DcisD calcium-binding motif for carbohydrate binding and that is widely spread among pro- and eukaryotes. Given the high abundance of high-mannose oligosaccharides in yeast cell walls, the Flo5A structure suggests a model for recognition, where social non-self- instead of unsocial self-interactions are favored.
authors.affiliation: Department of Chemistry/Biochemistry, Philipps-Universität Marburg, Hans-Meerwein-Strasse, D-35032 Marburg, Germany.
authors.forename: Maik
authors.initials: M
authors.lastname: Veelders
authors.forename: Stefan
authors.initials: S
authors.lastname: Brückner
authors.forename: Dimitri
authors.initials: D
authors.lastname: Ott
authors.forename: Carlo
authors.initials: C
authors.lastname: Unverzagt
authors.forename: Hans-Ulrich
authors.initials: HU
authors.lastname: Mösch
authors.forename: Lars-Oliver
authors.initials: LO
authors.lastname: Essen
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites / Q000235:genetics; D002118:Calcium / Q000378:metabolism; D002240:Carbohydrate Sequence; D018360:Crystallography, X-Ray; D037102:Lectins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008358:Mannose / Q000737:chemistry / Q000378:metabolism; D037601:Mannose-Binding Lectin / Q000737:chemistry / Q000378:metabolism; D008856:Microscopy, Fluorescence; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D009844:Oligosaccharides / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
chemical_list: C103472:FLO5 protein, S cerevisiae; D037102:Lectins; D037601:Mannose-Binding Lectin; D009844:Oligosaccharides; D029701:Saccharomyces cerevisiae Proteins; D008358:Mannose; D002118:Calcium