Cited by 24Metalloenzymes and iron-sulfur proteinsBacterial Genetics and BiotechnologyHemoglobin structure and function

Interaction of HoloCcmE with CcmF in Heme Trafficking and Cytochrome c Biosynthesis

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San Francisco, Brian, Kranz, Robert G.·2014·Journal of Molecular Biology

Abstract

The periplasmic heme chaperone holoCcmE is essential for heme trafficking in the cytochrome c biosynthetic pathway in many bacteria, archaea, and plant mitochondria. This pathway, called system I, involves two steps: (i) formation and release of holoCcmE (by the ABC-transporter complex CcmABCD) and (ii) delivery of the heme in holoCcmE to the putative cytochrome c heme lyase complex, CcmFH. CcmFH is believed to facilitate the final covalent attachment of heme (from holoCcmE) to the apocytochrome c. Although most models for system I propose that holoCcmE delivers heme directly to CcmF, no interaction between holoCcmE and CcmF has been demonstrated. Here, a complex between holoCcmE and CcmF is “trapped”, purified, and characterized. HoloCcmE must be released from the ABC-transporter complex CcmABCD to interact with CcmF, and the holo-form of CcmE interacts with CcmF at levels at least 20-fold higher than apoCcmE. Two conserved histidines (here termed P-His1 and P-His2) in separate periplasmic loops in CcmF are required for interaction with holoCcmE, and evidence that P-His1 and P-His2 function as heme-binding ligands is presented. These results show that heme in holoCcmE is essential for complex formation with CcmF and that the heme of holoCcmE is coordinated by P-His1 and P-His2 within the WWD domain of CcmF. These features are strikingly similar to formation of the CcmC:heme:CcmE ternary complex [Richard-Fogal C, Kranz RG. The CcmC:heme:CcmE complex in heme trafficking and cytochrome c biosynthesis. J Mol Biol 2010;401:350–62] and suggest common mechanistic and structural aspects.

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Authors
San Francisco, B., & Kranz, R. G.
Affiliations
Washington University in St. Louis (US)
Corresponding author
Kranz, Robert G.
Venue
Journal of Molecular Biology
Publisher
Elsevier BV
Published
2014-02
Volume
426
Issue
3
Pages
570-585
ISSN
0022-2836 (ISSN-L)
OpenAlex
W1987459562
Cited by
24
References
44
Citations by year
2026: 2 · 2025: 3 · 2023: 3 · 2022: 1 · 2021: 4 · 2018: 2 · 2017: 1 · 2016: 2 · 2015: 2 · 2014: 4
FWCI
0.97
Type
journal article
Language
en
Open access
Locations
  • Journal of Molecular Biology (publishedVersion)
  • PubMed (publishedVersion)
  • Europe PMC (PubMed Central) (acceptedVersion)
  • PubMed Central (acceptedVersion)
Funders
National Institutes of Health (R01 GM47909)
Topics
  • Physical Sciences › Energy › Renewable Energy, Sustainability and the Environment › Metalloenzymes and iron-sulfur proteins
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Genetics › Bacterial Genetics and Biotechnology
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Cell Biology › Hemoglobin structure and function
Keywords
heme trafficking, protein-protein interaction, archaea
MeSH terms
Amino Acid Sequence, Bacterial Outer Membrane Proteins, Escherichia coli, Genetic Complementation Test, Heme, Hemeproteins, Imidazoles, Molecular Sequence Data, Plasmids, Spectrophotometry, Ultraviolet, Holoenzymes, Protein Transport, Escherichia coli Proteins, Cytochromes c

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