Coupling electron cryomicroscopy and X-ray crystallography to understand secondary active transport.
In the past few years we have seen an amazing increase in the number of high-resolution structures for secondary transporters determined by X-ray crystallography, while 3D data obtained by electron cryomicroscopy (cryo-EM) from two-dimensional (2D) crystals are only available at medium resolutions of about 6-10A. Despite their superior resolution, it turned out that the description of a molecular mechanism of secondary transport could not solely rely on high-resolution X-ray structures and have to be supplemented with biochemical and spectroscopic data. Moreover, the comparison of X-ray structures and 3D EM maps has proved to be an important tool for validating native conformations of several membrane proteins, especially when functional data contradicted predictions based on a crystal structure. In addition, 3D EM maps are better suited to investigate transporter activation because of the lipidic environment.
Tsai
Ching-Ju
CJ
Biomolecular Research, Paul Scherrer Institute, 5232 Villigen, Switzerland.
Ziegler
Christine
C
D001693:Biological Transport, Active; D020285:Cryoelectron Microscopy / Q000379:methods*; D018360:Crystallography, X-Ray / Q000379:methods*; D006801:Humans; D026901:Membrane Transport Proteins / Q000737:chemistry* / Q000378:metabolism*; D011487:Protein Conformation
D026901:Membrane Transport Proteins