"Our images show that CETP is a small (53 kilodaltons) banana-shaped asymmetric molecule
with a tapered N-terminal domain and a globular C-terminal domain," Gang Ren, a materials physicist and electron microscopy expert with Berkeley Lab's Molecular Foundry, a DOE nanoscience research center, who led the study.
"We're assuming that the original asymmetric molecule
is the microtubule and that the dynein takes that asymmetry and converts it into cellular asymmetry."
The active form of the bacterial enzyme consists of four enzyme subunits that twist together into an asymmetric molecule
. Using X-ray diffraction, Ghosh and Duax pinpointed the "handcuffs" used by this chemical cop--the twists and kinks in its molecular structure that temporarily snare steroid molecules and a "cofactor" compound necessary to metabolize them.