Fig. 3: Structural and functional architecture of the biofilm regulator RemA.

a Two (RemA)₈ align back-to-back via their α1-helices to form a 16-mer. The color code is as defined in Fig. (1a). b Within the 16-mer of RemA, helices α-1 mediate the interactions through electrostatic interaction. Proline 29 marks the beginning of helix α1. c LacZ promoter activity assays of wildtype RemA and its variants carrying amino acid changes within helix α1. Activity assays of a remA mutant strain (n = 5) and of complementation strains encoding inducible (+ IPTG), ectopic copies of wildtype RemA (n = 9), RemA-P29S (n = 3), RemA-R32A (n = 3), RemA-D36S (n = 3), RemA-D36A-D39A (n = 3), and RemA-D39A (n = 3) are presented. Each point represents the activity measured in a biological replicate. Data are presented as mean from independent experiments. Source data are provided as a source data file. d Biofilm formation of different RemA mutant strains. The scale bars shown correspond to 0.5 cm. Biofilm formation was analyzed in at least two independent experiments for each strain with several independently grown colonies per experiment. The colonies shown represent typical examples. e Front view of (RemA)₈ showing the positions of the arginines 18 of each subunit. f Arginine 18 established contacts between two RemA subunits of (RemA)₈. Replacement of arginine 18 into tryptophane in the RemA-R18W variant leads to a different contact pattern. g Front view of (RemA-R18W)₇ showing the positions of the tryptophanes 18 of each subunit. h LacZ promoter activity assays of wildtype RemA (n = 9) and the RemA-R18W variant (n = 4) in the presence of IPTG. Each point represents the activity measured in a biological replicate. Source data are provided as a source data file.