Fig. 4: Distinct properties of convergently evolved AdhE and BdhE multimers.

a The residues involved in inter-molecule interactions of AdhE and BdhE dimers. The red residues represent the interaction interfaces estimated by PICKLUSTER (without-clustering mode) implemented in ChimeraX-v1.7rc202311290355⁷⁶. The AdhE dimer structure of the extended conformation was retrieved from the Protein Data Bank (PDB ID: 6TQH). Loops 1-4 were annotated to the particular loop structures where inter-molecule interaction residues of AdhE or BdhE enriched. b The ALDH-ADH interaction interface of AdhE and BdhE. The green and purple loop structures represent the loops 1–4 and their homologous parts. c Multiple sequence alignment of BdhE, AdhE, and sister-clade single-domain families of them. All 47 BdhEs, randomly sampled 50 AdhEs, and randomly sampled 10 genes for each of the other families are shown. The positions corresponding to loops 1–4 are indicated by green and purple bars. d Comparison of RMSF distributions among dimers and hexamer/tetramer of AdhE and BdhE, respectively. RMSFs were calculated for every atom in each replicate run, and averaged across replicate runs. The RMSFs of an AdhE hexamer were calculated for the intermediate dimer unit. The asterisk indicates the statistical difference (Two-sided Wilcoxon signed rank test. P = 0.0035 and <2.23 × 10⁻³⁰⁸ for AdhE and BdhE, respectively.). e Histograms of RMSF differences for each atom between the AdhE hexamer and dimer, and between the BdhE tetramer and dimer. Positive and negative values indicate atoms that are more stable (i.e., have lower RMSF) in the dimer and in the hexamer/tetramer, respectively. The asterisk indicates the statistical difference (Two-sided Mann-Whitney U test. P = < 2.23 × 10⁻³⁰⁸.). Color mapping of RMSF onto the 3D structures of an AdhE hexamer (f), a BdhE tetramer (g), an AdhE dimer (h), and a BdhE dimer (i). In Fig. 4h and i, RMSFs calculated by molecular dynamics (MD) for dimer structures are shown on the left, and RMSFs for hexamer/tetramer structures mapped onto dimer structures are shown on the right, respectively. Source data are provided as a Source Data file.