|
The three-dimensional structure of Wolinella succinogenes quinol:fumarate
reductase (QFR), a dihaem-containing member of the superfamily of
succinate:quinone oxidoreductases (SQOR), has been determined at 2.2 A
resolution by X-ray crystallography [Lancaster et al., Nature 402 (1999)
377-385]. The structure and mechanism of W. succinogenes QFR and their relevance
to the SQOR superfamily have recently been reviewed [Lancaster, Adv. Protein
Chem. 63 (2003) 131-149]. Here, a comparison is presented of W. succinogenes QFR
to the recently determined structure of the mono-haem containing
succinate:quinone reductase from Escherichia coli [Yankovskaya et al., Science
299 (2003) 700-704]. In spite of differences in polypeptide and haem
composition, the overall topology of the membrane anchors and their relative
orientation to the conserved hydrophilic subunits is strikingly similar. A major
difference is the lack of any evidence for a 'proximal' quinone site, close to
the hydrophilic subunits, in W. succinogenes QFR.
|
