The characterization and distribution of the bHLH domains. A. Sequence logo of the SlybHLH domain by MEME. The H5, E9 and R12 amino acids in the basic domain that are important for DNA binding are indicated by stars. Amino acids important for dimerization of the helix-loop-helix domain are indicated by arrows. B. Distribution of amino acids in the bHLH consensus motif among tomatoes. The numbers of horizontal ordinate refer to the positions of the residues in the alignments of the studies. C. Predicted DNA-binding characteristics of the bHLH domain of SlybHLH proteins.