Fig. 2

Distribution and putative folding of Pir repeats. (A) Homologous Pir loci across the Saccharomyces clade. Only S. cerevisiae does not encode Pir6, a Cis3 homologue. Arrows denote gene orientation and numbers within them the number of Pir repeats. (B) Unrooted phylogenetic tree of 406 Pir homologues across 76 species of budding yeasts. Red points denote the positions of S. cerevisiae homologues. The bar height and colour in the outer rim show the number of Pir repeats in each homologue and its clade of origin, respectively. (C) Alphafold2 model of Hsp150 (Pir2) with folded Pir repeats. The colour scheme of the structural model and the summary tracks follow Fig. 1. (D) Sideview of the Hsp150 Pir repeats folded into two-faced β-helix, accentuating ordered folding of amino acid residues. Glutamine residues through which Pir proteins covalently bind to the cell wall are encircled in red