Reference "Structure of the electron transfer complex between ferredoxin and ferredoxin-NADP(+) reductase"

Reference ID

8403

Title

Structure of the electron transfer complex between ferredoxin and ferredoxin-NADP(+) reductase

Source

Nat Struct Biol, 2001, vol. 8, pp. 117-121

Authors (8)

Kurisu-G	Kusunoki-M
Katoh-E	Yamazaki-T
Teshima-K	Onda-Y
Kimata-Ariga-Y	Hase-T

Abstract

All oxygenic photosynthetically derived reducing equivalents are utilized by
combinations of a single multifuctional electron carrier protein, ferredoxin
(Fd), and several Fd-dependent oxidoreductases. We report the first crystal
structure of the complex between maize leaf Fd and Fd-NADP(+) oxidoreductase
(FNR). The redox centers in the complex--the 2Fe-2S cluster of Fd and flavin
adenine dinucleotide (FAD) of FNR--are in close proximity; the shortest
distance is 6.0 A. The intermolecular interactions in the complex are mainly
electrostatic, occurring through salt bridges, and the interface near the
prosthetic groups is hydrophobic. NMR experiments on the complex in solution
confirmed the FNR recognition sites on Fd that are identified in the crystal
structure. Interestingly, the structures of Fd and FNR in the complex and in
the free state differ in several ways. For example, in the active site of FNR,
Fd binding induces the formation of a new hydrogen bond between side chains of
Glu 312 and Ser 96 of FNR. We propose that this type of molecular
communication not only determines the optimal orientation of the two proteins
for electron transfer, but also contributes to the modulation of the enzymatic
properties of FNR.