posted on 2022-04-25, 22:12authored byHasan DeMirci, Yashas Rao, Gabriele M. Stoffel, Bastian Vögeli, Kristina Schell, Aharon Gomez, Alexander Batyuk, Cornelius Gati, Raymond G. Sierra, Mark S. Hunter, E. Han Dao, Halil I. Ciftci, Brandon Hayes, Fredric Poitevin, Po-Nan Li, Manat Kaur, Kensuke Tono, David Adrian Saez, Samuel Deutsch, Yasuo Yoshikuni, Helmut Grubmüller, Tobias J. Erb, Esteban Vöhringer-Martinez, Soichi Wakatsuki
Enoyl-CoA carboxylases/reductases
(ECRs) are some of the most efficient
CO2-fixing enzymes described to date. However, the molecular
mechanisms underlying the extraordinary catalytic activity of ECRs
on the level of the protein assembly remain elusive. Here we used
a combination of ambient-temperature X-ray free electron laser (XFEL)
and cryogenic synchrotron experiments to study the structural organization
of the ECR from Kitasatospora setae. The K. setae ECR is a homotetramer
that differentiates into a pair of dimers of open- and closed-form
subunits in the catalytically active state. Using molecular dynamics
simulations and structure-based mutagenesis, we show that catalysis
is synchronized in the K. setae ECR
across the pair of dimers. This conformational coupling of catalytic
domains is conferred by individual amino acids to achieve high CO2-fixation rates. Our results provide unprecedented insights
into the dynamic organization and synchronized inter- and intrasubunit
communications of this remarkably efficient CO2-fixing
enzyme during catalysis.