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Imaging live cells at nanometre resolution is challenging because radiation damage kills the cells during exposure. Here, the authors overcome this difficulty in a ‘diffraction before destruction’ experiment using an X-ray laser and record signal to 4 nm resolution on a free-flying cell.

70,000 diffraction patterns captured over twelve minutes at the Linac Coherent Light Source yield reconstructions of the smallest single biological objects imaged with an X-ray laser.

Researchers describe a mechanism capable of compressing fast and intense X-ray pulses through the rapid loss of crystalline periodicity. It is hoped that this concept, combined with X-ray free-electron laser technology, will allow scientists to obtain structural information at atomic resolutions.

Lipidic sponge phase crystallization yields membrane protein microcrystals that can be injected into an X-ray free electron laser beam, yielding diffraction patterns that can be processed to recover the crystal structure.

Serial femtosecond crystallography using X-ray free-electron lasers has huge potential for time-resolved structural experiments. Here, the authors present a structure of the light-driven proton pump bacteriorhodopsin using these techniques.

Pump–probe measurements conventionally achieve femtosecond time resolution for X-ray crystallography of reactive processes, but the measured structural dynamics are complex. Using coherent control techniques, we show that the ultrafast crystallographic differences of a fluorescent protein are dominated by ground-state vibrational processes that are unconnected to the photoisomerization reaction of the chromophore.

The start-up of the new femtosecond hard X-ray laser facility in Stanford, the Linac Coherent Light Source, has brought high expectations for a new era for biological imaging. The intense, ultrashort X-ray pulses allow diffraction imaging of small structures before radiation damage occurs. This new capability is tested for the problem of imaging a non-crystalline biological sample. Images of mimivirus are obtained, the largest known virus with a total diameter of about 0.75 micrometres, by injecting a beam of cooled mimivirus particles into the X-ray beam. The measurements indicate no damage during imaging and prove the concept of this imaging technique.

Structural and physiological studies show that the inner membrane protein PbgA is a crucial sensor of lipopolysaccharide (LPS) and regulates the activity of the LPS biosynthesis enzyme LpxC.

Serial femtosecond crystallography is an X-ray free-electron-laser-based method that uses X-ray bursts to determine protein structures. Here the authors present the structure of a photosynthetic reaction centre, an integral membrane protein, achieved with no sign of X-ray-induced radiation damage.

Time-resolved serial femtosecond crystallography is used to reveal the structural changes that stabilize the charge-separation steps of electron-transfer reactions in the photosynthetic reaction centre of Blastochloris viridis on a timescale of picoseconds.

The structure of the bacterial toxin BinAB, which is used to combat mosquito-borne diseases, reveals pH-sensitive switches and carbohydrate-binding modules that may contribute to the larvicidal function of the toxin.

The start-up of the new femtosecond hard X-ray laser facility in Stanford, the Linac Coherent Light Source, has brought high expectations for a new era for biological imaging. The intense, ultrashort X-ray pulses allow diffraction imaging of small structures before radiation damage occurs. This new capability is tested for the problem of structure determination from nanocrystals of macromolecules that cannot be grown in large crystals. Over three million diffraction patterns were collected from a stream of nanocrystals of the membrane protein complex photosystem I, which allowed the assembly of a three-dimensional data set for this protein, and proves the concept of this imaging technique.

XFEL radiation is providing new opportunities for probing biological systems. Here the authors perform nanoscale x-ray imaging of microtubules with helical symmetry, by using imaging sorting and reconstruction techniques.

X-ray spectroscopy is a tool used for the investigation of aqueous solutions but the strong absorption of water means that very thin liquid sheets are needed for accurate analysis. Here the authors produce free-flowing liquid sheets 2 orders of magnitude thinner than sheets obtained with existing techniques.

Liquid ultrafast electron scattering measures structural responses in liquid water with femtosecond temporal and atomic spatial resolution to reveal a transient hydrogen bond contraction then thermalization preceding relaxation of the OH stretch.

Expression of a protein in Sf9 insect cells at high concentration triggers formation of in vivo crystals that can be analyzed by serial femtosecond X-ray crystallography.

A 'protein quake' is directly monitored on the picosecond timescale using the method of time-resolved wide-angle X-ray scattering at an X-ray free-electron laser.

Femtosecond X-ray pulses were used to obtain diffraction data on photosystem II, revealing conformational changes as the complex transitions from the dark S₁ state to the double-pumped S₃ state; the time-resolved serial femtosecond crystallography technique enables structural determination of protein conformations that are highly prone to traditional radiation damage.

A high-speed liquid jet delivery system improves the X-ray footprinting and mass spectrometry method to label proteins for structural studies.