6CUK

Engineered Cytochrome c from Rhodothermus marinus, Rma TDE

Summary for 6CUK

• Entry DOI: 10.2210/pdb6cuk/pdb
• Descriptor: Cytochrome c, HEME C (3 entities in total)
• Functional Keywords: carbene transferase, silicon-carbon bond, lyase
• Biological source: Rhodothermus marinus (Rhodothermus obamensis)
• Total number of polymer chains: 1
• Total formula weight: 14648.29

Authors

Lewis, R.D.,Buller, A.R.,Arnold, F.H. (deposition date: 2018-03-26, release date: 2018-06-27, Last modification date: 2024-10-09)

Primary citation

Lewis, R.D.,Garcia-Borras, M.,Chalkley, M.J.,Buller, A.R.,Houk, K.N.,Kan, S.B.J.,Arnold, F.H.
Catalytic iron-carbene intermediate revealed in a cytochromeccarbene transferase.
Proc. Natl. Acad. Sci. U.S.A., 115:7308-7313, 2018

PubMed Abstract: Recently, heme proteins have been discovered and engineered by directed evolution to catalyze chemical transformations that are biochemically unprecedented. Many of these nonnatural enzyme-catalyzed reactions are assumed to proceed through a catalytic iron porphyrin carbene (IPC) intermediate, although this intermediate has never been observed in a protein. Using crystallographic, spectroscopic, and computational methods, we have captured and studied a catalytic IPC intermediate in the active site of an enzyme derived from thermostable () cytochrome High-resolution crystal structures and computational methods reveal how directed evolution created an active site for carbene transfer in an electron transfer protein and how the laboratory-evolved enzyme achieves perfect carbene transfer stereoselectivity by holding the catalytic IPC in a single orientation. We also discovered that the IPC in cytochrome has a singlet ground electronic state and that the protein environment uses geometrical constraints and noncovalent interactions to influence different IPC electronic states. This information helps us to understand the impressive reactivity and selectivity of carbene transfer enzymes and offers insights that will guide and inspire future engineering efforts.

PubMed: 29946033
DOI: 10.1073/pnas.1807027115

Experimental method

X-RAY DIFFRACTION (1.47 Å)