Chlorophyll a/b binding-specificity in water-soluble chlorophyll protein

Nat Plants. 2018 Nov;4(11):920-929. doi: 10.1038/s41477-018-0273-z. Epub 2018 Oct 8.


We altered the chlorophyll (Chl) binding sites in various versions of water-soluble chlorophyll protein (WSCP) by amino acid exchanges to alter their preferences for either Chl a or Chl b. WSCP is ideally suited for this mutational analysis since it forms a tetrameric complex with only four identical Chl binding sites. A loop of 4-6 amino acids is responsible for Chl a versus Chl b selectivity. We show that a single amino acid exchange within this loop changes the relative Chl a/b affinities by a factor of 40. We obtained crystal structures of this WSCP variant binding either Chl a or Chl b. The Chl binding sites in these structures were compared with those in the major light-harvesting complex (LHCII) of the photosynthetic apparatus in plants to search for similar structural features involved in Chl a/b binding specificity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Binding Sites
  • Brassica
  • Chlorophyll / chemistry
  • Chlorophyll / genetics
  • Chlorophyll / metabolism*
  • Chlorophyll A / chemistry
  • Chlorophyll A / genetics
  • Chlorophyll A / metabolism*
  • Lepidium
  • Protein Binding
  • Protein Structure, Tertiary
  • Sequence Alignment
  • Water / metabolism


  • Water
  • Chlorophyll
  • chlorophyll b
  • Chlorophyll A