So far the method of choice for the determination of the atomic structures of membrane proteins has been X-ray crystallography with protein production and crystallization as the bottlenecks. With the advent of single particle electron cryomicroscopy (Nobel Prize 2017) this may change.
We determined the first structure of a cytochrome bd oxidase, a potential target to fight tuberculosis, at a resolution of about 3.2 Å by X-ray crystallography after ten years of extensive work (Safarian et al., Science 352, 583-586 (2016)). Most recently we determined the structure of a bd oxidase from a different organism at a resolution of about 2.7 Å by cryoEM after 6 months of work. Not only is the quality of the cryoEM structure better, but also the enzyme appears to be more native, and much less material is required!