Low-resolution structure determination of Na⁺-translocating NADH: ubiquinone oxidoreductase from Vibrio cholerae by ab initio phasing and electron microscopy

Acta Cryst. (2012). D68, 724-731 (http://doi.org/h92)

Overlay of the 16 Å crystal structure (yellow) and the EM reconstruction (grey). (a) Side view, (b) top view of the Na⁺-NQR complex.

A 16 Å resolution envelope of the membrane protein Na⁺-NQR was determined by connectivity-based ab initio phasing. The found envelope was used as a reference in three-dimensional reconstruction of the Na⁺-NQR from negative-stain EM images. The two methods displayed similar dimensions and features of the particle. Despite the resolution limitations, the method could provide important structural information in many X-ray crystallographic projects where the molecule of interest is a membrane protein or membrane protein complex yielding crystals of low diffractive power.