Crystallization of mitochondrial rhodoquinol-fumarate reductase from the parasitic nematode Ascaris suum with the specific inhibitor flutolanil.

In adult Ascaris suum (roundworm) mitochondrial membrane-bound complex II acts as a rhodoquinol-fumarate reductase, which is the reverse reaction to that of mammalian complex II (succinate-ubiquinone reductase). The adult A. suum rhodoquinol-fumarate reductase was crystallized in the presence of octaethyleneglycol monododecyl ether and n-dodecyl-beta-D-maltopyranoside in a 3:2 weight ratio. The crystals belonged to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 123.75, b = 129.08, c = 221.12 A, and diffracted to 2.8 A resolution using synchrotron radiation. The presence of two molecules in the asymmetric unit (120 kDa x 2) gives a crystal volume per protein mass (V(M)) of 3.6 A(3) Da(-1).