8U66

Firmicutes Rubisco

Summary for 8U66

• Entry DOI: 10.2210/pdb8u66/pdb
• EMDB information: 41946
• Descriptor: Rubisco, MAGNESIUM ION, 2-CARBOXYARABINITOL-1,5-DIPHOSPHATE, ... (4 entities in total)
• Functional Keywords: carboxylase, oxygenase, lyase
• Biological source: Bacillota
• Total number of polymer chains: 8
• Total formula weight: 410874.20

Authors

Kaeser, B.P.,Liu, A.K.,Shih, P.M. (deposition date: 2023-09-13, release date: 2023-11-22, Last modification date: 2025-05-28)

Primary citation

Liu, A.K.,Kaeser, B.,Chen, L.,West-Roberts, J.,Taylor-Kearney, L.J.,Lavy, A.,Gunzing, D.,Li, W.J.,Hammel, M.,Nogales, E.,Banfield, J.F.,Shih, P.M.
Deep-branching evolutionary intermediates reveal structural origins of form I rubisco.
Curr.Biol., 33:5316-5325.e3, 2023

PubMed Abstract: The enzyme rubisco (ribulose-1,5-bisphosphate carboxylase/oxygenase) catalyzes the majority of biological carbon fixation on Earth. Although the vast majority of rubiscos across the tree of life assemble as homo-oligomers, the globally predominant form I enzyme-found in plants, algae, and cyanobacteria-forms a unique hetero-oligomeric complex. The recent discovery of a homo-oligomeric sister group to form I rubisco (named form I') has filled a key gap in our understanding of the enigmatic origins of the form I clade. However, to elucidate the series of molecular events leading to the evolution of form I rubisco, we must examine more distantly related sibling clades to contextualize the molecular features distinguishing form I and form I' rubiscos. Here, we present a comparative structural study retracing the evolutionary history of rubisco that reveals a complex structural trajectory leading to the ultimate hetero-oligomerization of the form I clade. We structurally characterize the oligomeric states of deep-branching form Iα and I'' rubiscos recently discovered from metagenomes, which represent key evolutionary intermediates preceding the form I clade. We further solve the structure of form I'' rubisco, revealing the molecular determinants that likely primed the enzyme core for the transition from a homo-oligomer to a hetero-oligomer. Our findings yield new insight into the evolutionary trajectory underpinning the adoption and entrenchment of the prevalent assembly of form I rubisco, providing additional context when viewing the enzyme family through the broader lens of protein evolution.

PubMed: 37979578
DOI: 10.1016/j.cub.2023.10.053

Experimental method

ELECTRON MICROSCOPY (2.21 Å)