A new paradigm for macromolecular crystallography beamlines derived from high-pressure methodology and results

Macromolecular crystallography at high pressure (HPMX) is a mature technique. Shorter X-ray wavelengths increase data collection efficiency on cryocooled crystals. Extending applications and exploiting spin-off of HPMX will require dedicated synchrotron radiation beamlines based on a new paradigm

Adaptation of the base-paired double-helix molecular architecture to extreme pressure

The behaviour of the d(GGTATACC) oligonucleotide has been investigated by X-ray crystallography at 295 K in the range from ambient pressure to 2 GPa (∼20 000 atm). Four 3D-structures of the A-DNA form (at ambient pressure, 0.55, 1.09 and 1.39 GPa) were refined at 1.60 or 1.65 Å resolution. In addition to the diffraction pattern of the A-form, the broad meridional streaks previously explained by occluded B-DNA octamers within the channels of the crystalline A-form matrix were observed up to at least 2 GPa. This work highlights an important property of nucleic acids, their capability to withstand very high pressures, while keeping in such conditions a nearly invariant geometry of base pairs that store and carry genetic information. The double-helix base-paired architecture behaves as a molecular spring, which makes it especially adapted to very harsh conditions. These features may have contributed to the emergence of a RNA World at prebiotic stage

Effects of high hydrostatic pressure per se and high argon pressure on urate oxidase-ligand stabilization

CERVOXYNational audienc

Analyse de l'urate oxydase sous haute pression hydrostatique avec deux typrs de cellules : une cellule à enclume diamant et une cellule sous pression d'argon

CERVOXYNational audienc

Behavior of B- and Z-DNA Crystals under High Hydrostatic Pressure

CERVOXYInternational audienceSingle crystals of B-DNA and Z-DNA oligomers were analyzed under high hydrostatic pressure and their behavior compared to the A-DNA crystals already known. The amplitude of the base compression, when compared to the A-form of DNA (0.13 Å/GPa), was higher for the Z DNA (0.32 Å/GPa) and was the highest for the B-DNA (0.42 Å/GPa). The B-DNA crystal degraded rapidly around 400-500 MPa while the Z-structure was more resistant, up to 1.2 GPa

Equilibria between conformational states of the Ras oncogene protein revealed by high ressure crystallography

CERVOXYInternational audienc

Comparative study of the effects of high hydrostatic pressure per se and high argon pressure on urate oxidase ligand stabilization

CERVOXYInternational audienceThe stability of the tetrameric enzyme urate oxidase in complex with excess of 8-azaxanthine was investigated either under high hydrostatic pressure per se or under a high pressure of argon. The active site is located at the interface of two subunits, and the catalytic activity is directly related to the integrity of the tetramer. This study demonstrates that applying pressure to a protein–ligand complex drives the thermodynamic equilibrium towards ligand saturation of the complex, revealing a new binding site. A transient dimeric intermediate that occurs during the pressure-induced dissociation process was characterized under argon pressure and excited substates of the enzyme that occur during the catalytic cycle can be trapped by pressure. Comparison of the different structures under pressure infers an allosteric role of the internal hydrophobic cavity in which argon is bound, since this cavity provides the necessary flexibility for the active site to function

Equilibria between conformational states of the Ras oncogene protein revealed by high ressure crystallography

CERVOXYInternational audienc

High pressure macromolecular crystallography revealed equilibria between conformational states of the Ras oncogene protein

CERVOXYNational audienc