8CEA

Cytochrome c maturation complex CcmABCD, E154Q

Summary for 8CEA

• Entry DOI: 10.2210/pdb8cea/pdb
• EMDB information: 16602
• Descriptor: Cytochrome c biogenesis ATP-binding export protein CcmA, Heme exporter protein B, Heme exporter protein C, ... (4 entities in total)
• Functional Keywords: cytochrome c maturation, membrane protein
• Biological source: Escherichia coli K-12; More
• Total number of polymer chains: 6
• Total formula weight: 131751.18

Authors

Ilcu, L.,Zhang, L.,Einsle, O. (deposition date: 2023-02-01, release date: 2023-09-06)

Primary citation

Ilcu, L.,Denkhaus, L.,Brausemann, A.,Zhang, L.,Einsle, O.
Architecture of the Heme-translocating CcmABCD/E complex required for Cytochrome c maturation.
Nat Commun, 14:5190-5190, 2023

PubMed Abstract: Mono- and multiheme cytochromes c are post-translationally matured by the covalent attachment of heme. For this, Escherichia coli employs the most complex type of maturation machineries, the Ccm-system (for cytochrome c maturation). It consists of two membrane protein complexes, one of which shuttles heme across the membrane to a mobile chaperone that then delivers the cofactor to the second complex, an apoprotein:heme lyase, for covalent attachment. Here we report cryo-electron microscopic structures of the heme translocation complex CcmABCD from E. coli, alone and bound to the heme chaperone CcmE. CcmABCD forms a heterooctameric complex centered around the ABC transporter CcmAB that does not by itself transport heme. Our data suggest that the complex flops a heme group from the inner to the outer leaflet at its CcmBC interfaces, driven by ATP hydrolysis at CcmA. A conserved heme-handling motif (WxWD) at the periplasmic side of CcmC rotates the heme by 90° for covalent attachment to the heme chaperone CcmE that we find interacting exclusively with the CcmB subunit.

PubMed: 37626034
DOI: 10.1038/s41467-023-40881-y

Experimental method

ELECTRON MICROSCOPY (3.94 Å)