Fig. 5: Catalytic sites in the γCA domain. | Nature Plants

Fig. 5: Catalytic sites in the γCA domain.

From: Cryo-EM structure of the respiratory I + III2 supercomplex from Arabidopsis thaliana at 2 Å resolution

Fig. 5

Overview of the γCA domain (centre) with γCA1 (orange), γCA2 (yellow) and γCAL2 (red). a, Catalytic site at the γCA2–γCAL2 interface with bound butyryl- or crotonyl-CoA, here referred to as γCA-CoA-X (green). Subunits γCA2 and γCAL2 interact with the phosphate groups and the adenine ring of CoA-X either directly or across a chain (black dotted lines) of water molecules (red). The 3′ phosphate group adopts two alternative conformations, as indicated by two strong densities in the cryo-EM map (Extended Data Fig. 5). The butyryl or crotonyl group of CoA-X is located at the putative catalytic site of the γCAL2–γCA2 interface (grey dotted ellipse). b, Map density and fitted atomic model of the catalytic site at the γCA1–γCA2 interface. A zinc ion is coordinated by three histidines and one water molecule in tetrahedral geometry (red dotted lines). The active site is surrounded by a network of hydrogen bonds. For details, see Extended Data Figs. 5 and 6.

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