Related Experiment Video

Updated: Feb 24, 2026

Isolation and Characterization of Intact Phycobilisome in Cyanobacteria
06:26

Isolation and Characterization of Intact Phycobilisome in Cyanobacteria

Published on: November 10, 2021

4.8K

Maturation of Plastid c-type Cytochromes

Stéphane T Gabilly1,2, Patrice P Hamel1,2

  • 1Department of Molecular Genetics and Department of Biological Chemistry and Pharmacology, The Ohio State University, ColumbusOH, United States.

Frontiers in Plant Science
|August 12, 2017
PubMed

Insights

The cytochrome c synthesis (CCS) pathway is crucial for attaching heme to apocytochrome c in plastids, involving complex transport and ligation steps. This pathway, essential for photosynthesis, requires more components in plastids than in bacteria.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Photosynthesis Research

Background:

  • Cytochromes c are essential hemoproteins acting as electron carriers, characterized by a CXXCH heme-binding motif.
  • Plastids contain multiple cytochromes c, including cytochrome f, c6, and c6A, with roles in photosynthesis and unknown functions.
  • The conversion of apocytochrome c to holocytochrome c involves heme attachment via thioether linkages in the thylakoid lumen.

Purpose of the Study:

  • To investigate the cytochrome c synthesis (CCS) pathway responsible for heme attachment to plastid cytochromes c.
  • To elucidate the roles of CCS pathway components in heme transport and ligation.
  • To compare the CCS pathway complexity between plastids and other organisms like bacteria.

Main Methods:

  • Genetic analysis of photosynthetic-deficient mutants in Chlamydomonas reinhardtii to identify CCS genes.
  • Biochemical studies to understand the function of CCS proteins in heme delivery and ligation.
  • Comparative analysis of CCS pathway components across different organisms.

Main Results:

  • The CCS pathway, involving genes like CCS1 and CcsA, is essential for plastid cytochrome c assembly.
  • CcsA and CCS1 are polytopic membrane proteins involved in heme delivery and heme ligation.
  • CCDA, CCS4, and CCS5 facilitate the delivery of reducing equivalents for thioether bond formation.
  • Plastid cytochrome c assembly requires at least eight CCS components, unlike the four needed in bacteria.

Conclusions:

  • The CCS pathway is conserved in cyanobacteria and bacteria but is more complex in plastids.
  • The intricate CCS pathway in plastids suggests a more nuanced biochemistry for thioether formation.
  • Understanding the CCS pathway is critical for comprehending photosynthesis and electron transport in plants and algae.

Keywords:
cytochrome b6fcytochrome chemephotosynthesisthioetherthylakoid lumen

More Related Videos

A New Approach for the Comparative Analysis of Multiprotein Complexes Based on 15N Metabolic Labeling and Quantitative Mass Spectrometry08:04

A New Approach for the Comparative Analysis of Multiprotein Complexes Based on 15N Metabolic Labeling and Quantitative Mass Spectrometry

Published on: March 13, 2014

12.7K
Plastoglobule Lipid Droplet Isolation from Plant Leaf Tissue and Cyanobacteria10:35

Plastoglobule Lipid Droplet Isolation from Plant Leaf Tissue and Cyanobacteria

Published on: October 6, 2022

3.4K

Related Concept Videos

Protein Transport to the Outer Chloroplast Membrane01:11

Protein Transport to the Outer Chloroplast Membrane

Chloroplast outer membrane proteins encoded by the nucleus are synthesized in the cytosol. Soon after synthesis, they bind cytosolic factors such as 14-3-3 protein and the Hsp70 chaperones that keep these precursors in an unfolded state until their translocation.
Two models describe the mechanism of precursor recognition and entry across the outer membrane through the TOC complex. Model 1 suggests the newly synthesized precursor binds to the TOC receptor 159 and forms a complex.
2.4K
Protein Transport to the Stroma01:24

Protein Transport to the Stroma

Chloroplasts are triple membrane structures with an outer membrane, an inner membrane, and a thylakoid membrane, each containing distinct metabolite transporters, membrane translocons, and enzymes. Appropriate sorting and translocating these proteins to their correct membrane systems is essential for chloroplast function.
Protein complexes called the translocon of the outer chloroplast membrane or TOC complex, and the translocon of the inner chloroplast membrane or TIC complex mediate the...
2.3K
Protein Transport to the Inner Chloroplast Membrane01:18

Protein Transport to the Inner Chloroplast Membrane

Proteins targeted to the inner chloroplast membrane, or plastid proteins, are transported by two general pathways: the stop-transfer and the re-insertion or post-import pathways. Most plastid proteins carry N-terminal transit sequences and internal import sequences targeting it to the specific chloroplast subcompartment. Proteins targeted by the stop-transfer pathway have internal hydrophobic sequences that inhibit their translocation into the stroma. As a result, these precursors are arrested...
2.5K
The Anatomy of Chloroplasts01:08

The Anatomy of Chloroplasts

Green algae and plants, including green stems and unripe fruit, harbor specialized organelles called chloroplasts to carry out photosynthesis. They coordinate both stages of photosynthesis — the light-dependent reactions and the light-independent reactions. The light-dependent reactions use sunlight to release oxygen and produce chemical energy in the form of ATP and NADPH, and the light-independent reactions capture CO2 and use ATP and NADPH to produce sugar.
Structure of...
8.6K
Protein Transport to the Thylakoids01:22

Protein Transport to the Thylakoids

Thylakoids are membrane-bound sac-like structures within the chloroplast that serve as sites for photosynthesis. Thylakoid lumen contains many electron transport proteins and is enclosed by a thylakoid membrane rich in the light-harvesting complex. Proteins targeted to the thylakoids are transported as precursors and are sorted by the general TOC/TIC import pathway. Once the precursor reaches the stroma, stromal processing peptidases remove their transit signal and expose thylakoid signal...
3.0K
Comparing Mitochondrial, Chloroplast, and Prokaryotic Genomes02:16

Comparing Mitochondrial, Chloroplast, and Prokaryotic Genomes

The present-day mitochondrial and chloroplast genomes have retained some of the characteristics of their ancestral prokaryotes and also have acquired new attributes during their evolution within eukaryotic cells. Like prokaryotic genomes, mitochondrial and chloroplast genomes neither bind with histone-like proteins nor show complex packaging into chromosome-like structures, as observed in eukaryotes. Unlike mitotic cell divisions observed in eukaryotic cells, mitochondria and chloroplasts...
17.2K