A productive NADP+ binding mode of ferredoxin-NADP + reductase revealed by protein engineering and crystallographic studies

Nat Struct Biol. 1999 Sep;6(9):847-53. doi: 10.1038/12307.

Abstract

The flavoenzyme ferredoxin-NADP+ reductase (FNR) catalyzes the production of NADPH during photosynthesis. Whereas the structures of FNRs from spinach leaf and a cyanobacterium as well as many of their homologs have been solved, none of these studies has yielded a productive geometry of the flavin-nicotinamide interaction. Here, we show that this failure occurs because nicotinamide binding to wild type FNR involves the energetically unfavorable displacement of the C-terminal Tyr side chain. We used mutants of this residue (Tyr 308) of pea FNR to obtain the structures of productive NADP+ and NADPH complexes. These structures reveal a unique NADP+ binding mode in which the nicotinamide ring is not parallel to the flavin isoalloxazine ring, but lies against it at an angle of approximately 30 degrees, with the C4 atom 3 A from the flavin N5 atom.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Amino Acid Substitution
  • Binding Sites
  • Crystallization
  • Crystallography, X-Ray*
  • Ferredoxin-NADP Reductase / chemistry*
  • Ferredoxin-NADP Reductase / genetics
  • Ferredoxin-NADP Reductase / metabolism*
  • Ligands
  • Models, Molecular
  • Molecular Sequence Data
  • NADP / chemistry
  • NADP / metabolism*
  • Pisum sativum / enzymology*
  • Protein Binding
  • Protein Conformation
  • Protein Engineering*
  • Spectrum Analysis
  • Thermodynamics
  • Tyrosine / genetics

Substances

  • Ligands
  • Tyrosine
  • NADP
  • Ferredoxin-NADP Reductase

Associated data

  • PDB/1QFY
  • PDB/1QFZ
  • PDB/1QGA