Crystal structures of the all cysteinyl coordinated D14C variant of Pyrococcus furiosus ferredoxin: [4Fe-4S] <-> [3Fe-4S] cluster conversion
Pernille Harris[1]
Molecular Tour
Structures of the all cysteinyl coordinated D14C variant of ferredoxin from the hyperthermophilic archaeon Pyrococcus furiosus have been determined for the [4Fe-4S] - and [3Fe-4S] forms.
The [4Fe-4S] form diffracted to 1.7 Å and two different types of molecules
were found in the crystal. They have different crystal packing and
intramolecular disulfide bond conformation. The crystal packing reveals a
beta-sheet interaction between A molecules in adjacent asymmetric units,
while B molecules are packed as monomers in a less rigid position next to the
A-A extended beta-sheet dimers. The intramolecular disulfide bond in the
A molecules is in a double conformation while the intramolecular disulfide
bond in the B molecules is in a single conformation.
Two forms of D14C [3Fe-4S] Pyrococcus furiosus ferredoxin are obtained
when purified at pH 8.0: a monomer and a dimer connected by an intermolecular
disulfide bond. When purified at pH 5.8, only the monomer is obtained.
The [3Fe-4S] form diffracted to 2.8 Å resolution and showed only the
monomeric form, which resembles molecule A of D14C [4Fe-4S]
Pyrococcus furiosus ferredoxin.
