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NO binding to the proapoptotic cytochrome c-cardiolipin complex

Michael A Hough1, Gary Silkstone1, J A R Worrall1

  • 1School of Biological Sciences, University of Essex, Colchester, United Kingdom.

Vitamins and Hormones
|September 6, 2014
PubMed

Insights

Cytochrome c, a key protein in cellular respiration, binds nitric oxide (NO) when complexed with cardiolipin. This interaction modulates the cell death pathway and NO levels.

Area of Science:

  • Biochemistry
  • Cell Biology
  • Molecular Biology

Background:

  • Cytochrome c is a mitochondrial heme protein essential for electron transport.
  • It interacts with cardiolipin, initiating apoptosis via peroxidase activity.
  • Cytochrome c binds ligands, including nitric oxide (NO).

Purpose of the Study:

  • To investigate the binding of nitric oxide (NO) to the cytochrome c/cardiolipin complex.
  • To understand how NO binding affects the proapoptotic function of cytochrome c.
  • To explore the structural implications of NO binding by comparing with cytochrome c'.

Main Methods:

  • Analysis of ligand binding to cytochrome c in complex with cardiolipin.
  • Comparison of NO binding modes with cytochrome c'-type proteins and guanylate cyclase.
  • Utilizing X-ray structural data of cytochrome c' for comparative insights.

Main Results:

  • Cytochrome c within the cardiolipin complex exhibits rapid ligand binding, including NO.
  • In its ferrous form, NO preferentially binds to the heme's proximal side.
  • This binding mode resembles that of cytochrome c' and guanylate cyclase.

Conclusions:

  • Nitric oxide binding to the cytochrome c/cardiolipin complex can modulate the apoptotic response.
  • This interaction may serve to buffer cellular nitric oxide concentrations.
  • Structural comparisons provide insights into the complex's function and NO interaction.

Keywords:
ApoptosisCardiolipinCytochrome c′Proximal bindingSoluble guanylate cyclase

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