High-resolution structure of the heat-stable form-IAq RuBisCO from the thermophilic purple sulfur bacterium Thermochromatium tepidum.

ABSTRACT: Ribulose 1,5-bisphosphate carboxylase/oxygenase (RuBisCO) catalyzes the initial carbon fixation reaction in the Calvin-Benson-Bassham cycle. Among the many forms of RuBisCOs, form-I-a protein complex containing 8 large and 8 small subunits-is the most common, representing over 90% of all known RuBisCOs. Although many form-I RuBisCO structures have been determined, no structure has been reported for a form-IAq RuBisCO. Here, we detail the structure of the heat-stable form-IAq RuBisCO from the thermophilic and anaerobic purple bacterium Thermochromatium (Tch.) tepidum at 1.55 Å resolution. The overall structure of the Tch. tepidum form-IAq RuBisCO resembles both a form-IAc RuBisCO from a chemolithotrophic sulfur bacterium and a synthetic form-I RuBisCO reconstructed from ancestral sequences.

SUBMITTER: Chang S 

PROVIDER: S-EPMC12216891 | biostudies-literature | 2025 Jul

REPOSITORIES: biostudies-literature