9LDL

The complex structure of Halomonas eurihalina BdhE

Summary for 9LDL

• Entry DOI: 10.2210/pdb9ldl/pdb
• EMDB information: 63004
• Descriptor: Aldehyde dehydrogenase family protein (1 entity in total)
• Functional Keywords: complex, enzyme, biosynthetic protein
• Biological source: Halomonas eurihalina
• Total number of polymer chains: 4
• Total formula weight: 377877.22

Authors

Konno, N.,Miyake, K.,Nishino, S.,Omae, K.,Yanagisawa, H.,Tsuru, S.,Kikkawa, M.,Furusawa, C.,Iwasaki, W. (deposition date: 2025-01-06, release date: 2025-10-01, Last modification date: 2025-10-15)

Primary citation

Konno, N.,Miyake, K.,Nishino, S.,Omae, K.,Yanagisawa, H.,Tsuru, S.,Nishimura, Y.,Kikkawa, M.,Furusawa, C.,Iwasaki, W.
Repeatability of protein structural evolution following convergent gene fusions.
Nat Commun, 16:8278-8278, 2025

PubMed Abstract: Convergent evolution of proteins provides insights into repeatability of genetic adaptation. While local convergence of proteins at residue or domain level has been characterized, global structural convergence by inter-domain/molecular interactions remains largely unknown. Here we present structural convergent evolution on fusion enzymes of aldehyde dehydrogenases (ALDHs) and alcohol dehydrogenases (ADHs). We discover BdhE (bifunctional dehydrogenase E), an enzyme clade that emerged independently from the previously known AdhE family through distinct gene fusion events. AdhE and BdhE show shared enzymatic activities and non-overlapping phylogenetic distribution, suggesting common functions in different species. Cryo-electron microscopy reveals BdhEs form donut-like homotetramers, contrasting AdhE's helical homopolymers. Intriguingly, despite distinct quaternary structures and < 30% amino acid sequence identity, both enzymes forms resemble dimeric structure units by ALDH-ADH interactions via convergently elongated loop structures. These findings suggest convergent gene fusions recurrently led to substrate channeling evolution to enhance two-step reaction efficiency. Our study unveils structural convergence at inter-domain/molecular level, expanding our knowledges on patterns behind molecular evolution exploring protein structural universe.

PubMed: 40983608
DOI: 10.1038/s41467-025-63898-x

Experimental method

ELECTRON MICROSCOPY (2.55 Å)