Overexpression, purification, and crystallization of eukaryotic membrane proteins represent a major challenge for structural biology. In recent years, we have solved the crystal structures of the human glucose transporters GLUT1 in the inward-open conformation at 3.17 Å resolution and GLUT3 in the outward-open and occluded conformations at 2.4 and 1.5 Å resolutions, respectively. Structural elu...

Membrane proteins represent between 20 and 30 percent of encoded protein in most genomes. Their functions are capital for the cell surviving and are the target of more than 50% of the modern drugs. However, their structural studies remain challenging. Indeed, less than 1% of the protein structures published in Protein Data Bank are membrane proteins. The main limitation is crystallization diffi...

Membrane proteins are the main functional units of biological membranes. They represent roughly one-third of the proteins encoded in the genome and about 70% of drugs are targeted to membrane proteins. X-ray protein crystallography is one of the most powerful tools to determine protein structure and to provide a basis for understanding molecular mechanisms of protein function. Despite an obviou...

A simple and inexpensive protocol for producing crystals in the sticky and viscous mesophase used for membrane protein crystallization by the in meso method is described. It provides crystals that appear within 15-30 min of setup at 293 K. The protocol gives the experimenter a convenient way of gaining familiarity and a level of comfort with the lipidic cubic mesophase, which can be daunting as...

Despite significant progress in high-throughput methods in macromolecular crystallography, the production of diffraction-quality crystals remains a major bottleneck. By recording diffraction in situ from crystals in their crystallization plates at room temperature, a number of problems associated with crystal handling and cryoprotection can be side-stepped. Using a dedicated goniometer installe...

Electron cryomicroscopy, or cryoEM, is an emerging technique for studying the three-dimensional structures of proteins and large macromolecular machines. Electron crystallography is a branch of cryoEM in which structures of proteins can be studied at resolutions that rival those achieved by X-ray crystallography. Electron crystallography employs two-dimensional crystals of a membrane protein em...

Many interesting and important membrane proteins are hetero-oligomeric. However, besides naturally abundant examples, the structures of relatively few such complexes are known. Partly, this is due to difficulties in expression, stoichiometric assembly, and in the evaluation of their stability prior to crystallization trials. Here we describe a new approach, which allows rapid assessment of prot...

We are testing a strategy for creating three-dimensional crystals of integral membrane proteins which involves the addition of a large soluble domain to the membrane protein to provide crystallization contacts. As a test of this strategy we designed a fusion between the membrane protein bacteriorhodopsin (BR) and the catalytic subunit of aspartyl transcarbamylase from Escherichia coli. The fusi...

Precise protein structure determination provides significant information on life science research, although high-quality crystals are not easily obtained. We developed a system for producing high-quality protein crystals with high throughput. Using this system, gravity-controlled crystallization are made possible by a magnetic microgravity environment. In addition, in-situ and real-time observa...

The Pi sampling method is derived from the incomplete factorial approach to macromolecular crystallization screen design. The resulting `Pi screens' have a modular distribution of a given set of up to 36 stock solutions. Maximally diverse conditions can be produced by taking into account the properties of the chemicals used in the formulation and the concentrations of the corresponding solution...