Binding of ferredoxin to algal photosystem I involves a single binding site and is composed of two thermodynamically distinct events

Pini Marco, Marina Kozuleva, Haviva Eilenberg, Yuval Mazor, Peter Gimeson, Andrey Kanygin, Kevin Redding, Iddo Weiner, Iftach Yacoby

Research output: Contribution to journalArticle

4 Citations (Scopus)


Despite the impressive progress made in recent years in understanding the early steps in charge separation within the photosynthetic reaction centers, our knowledge of how ferredoxin (Fd) interacts with the acceptor side of photosystem I (PSI) is not as well developed. Fd accepts electrons after transiently docking to a binding site on the acceptor side of PSI. However, the exact location, as well as the stoichiometry, of this binding have been a matter of debate for more than two decades. Here, using Isothermal Titration Calorimetry (ITC) and purified components from wild type and mutant strains of the green algae Chlamydomonas reinhardtii we show that PSI has a single binding site for Fd, and that the association consists of two distinct binding events, each with a specific association constant.

Original languageEnglish
Pages (from-to)234-243
Number of pages10
JournalBiochimica et Biophysica Acta - Bioenergetics
Issue number4
Publication statusPublished - Apr 2018



  • Chlamydomonas reinhardtii
  • Ferredoxin
  • Isothermal titration calorimetry
  • Photosystem I
  • Protein-protein interactions

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Cell Biology

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