Fig. 1: HeR genes flanked by neighboring genes in the same operon.

Phylogenetic trees between the HeRs (total: 448 heliorhodopsin sequences) in organisms (a) and HeRs (79 heliorhodopsin sequences) (b). a Each group of organisms is indicated by a thin-colored donut curve. HeR roots in which at least two genes (helR with adjacent genes in the same operon) are predicted to be transcribed by a single promoter and are indicated by the same color belonging to the groups. The percentages of helR with adjacent genes per total helR are labeled next to each group. b Total helR (n = 448), genes adjacent to helR (n = 173), and frequent neighboring genes (n = 79) are indicated by white, gray, and dark gray pie donut curves. helR and adjacent genes in the same operon were analyzed. The adjacent genes were classified into ten groups. Each group is indicated by different colored texts and circles. c, e The amino acids of each HeR at the residue positions in OcHeR are counted and normalized by the number of each total HeR, that is, amino acid frequency per HeR. c Difference in amino acid frequency per HeR in the classified ten groups compared to non-co-transcription group (helR alone). Residues that increased and decreased by more than 0.19 are marked as upper and lower stack-bars, respectively. e Amino acid frequency per HeR in total HeRs (n = 448). d Blue and red surfaces in the electrostatic potential distribution of OcHeR present positively and negatively charged residues, respectively. Red and blue correspond to potentials of 20 kT e⁻¹ and −20 kT e⁻¹, respectively. The structure is viewed from membrane angles, and yellow dotted rectangles indicate ICLs. ICL intracellular loop, NA not aligned position, EC extracellular side, CP cytoplasmic side.