8u66

Publication Abstract from PubMed

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 Ialpha 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.

Deep-branching evolutionary intermediates reveal structural origins of form I rubisco.,Liu AK, Kaeser B, Chen L, West-Roberts J, Taylor-Kearney LJ, Lavy A, Gunzing D, Li WJ, Hammel M, Nogales E, Banfield JF, Shih PM Curr Biol. 2023 Dec 18;33(24):5316-5325.e3. doi: 10.1016/j.cub.2023.10.053. Epub , 2023 Nov 17. PMID:37979578^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.