Identifying structural and dynamic changes during the Biliverdin Reductase B catalytic cycle
Biliverdin Reductase B (BLVRB) is an NADPH-dependent reductase that catalyzes the reduction of multiple substrates and is therefore considered a critical cellular redox regulator. In this study, we sought to address whether both structural and dynamics changes occur between different intermediates of the catalytic cycle and whether these were relegated to just the active site or the entirety of the enzyme.
Determining biomolecular structures near room temperature using X-ray crystallography: Concepts, methods and future optimization
For roughly two decades, cryocrystallography has been the overwhelmingly dominant method for determining high-resolution biomolecular structures.
MW-level Pulses from an All-Fiber and Self-Starting Femtosecond Oscillator
We present an all-fiber Mamyshev oscillator that generates 40 fs and 80 nJ pulses. The resulting 1.5-MW peak power is 20 times higher than that of prior all-fiber and self-starting lasers. Â© Optica Publishing Group 2022, Â© 2022 The Author(s)
Megawatt pulses from an all-fiber and self-starting femtosecond oscillator
Mamyshev oscillators produce high-performance pulses, but technical and practical issues render them unsuitable for widespread use. Here we present a Mamyshev oscillator with several key design features that enable self-starting operation and unprecedented performance and simplicity from an all-fiber laser. The laser generates 110 nJ pulses that compress to 40 fs and 80 nJ with a grating pair.
High-resolution single-particle cryo-EM of samples vitrified in boiling nitrogen
Based on work by Dubochet and others in the 1980s and 1990s, samples for single-particle cryo-electron microscopy (cryo-EM) have been vitrified using ethane, propane or ethane/propane mixtures. These liquid cryogens have a large difference between their melting and boiling temperatures and so can absorb substantial heat without formation of an insulating vapor layer adjacent to a cooling sample.
Millisecond mix-and-quench crystallography (MMQX) enables time-resolved studies of PEPCK with remote data collection
Time-resolved crystallography of biomolecules in action has advanced rapidly as methods for serial crystallography have improved, but the large number of crystals and the complex experimental infrastructure that are required remain serious obstacles to its widespread application. Here, millisecond mix-and-quench crystallography (MMQX) has been developed, which yields millisecond time-resolved data using far fewer crystals and routine remote synchrotron data collection.
Generation of 70-nJ and 40-fs Pulses by a Ring Mamyshev Oscillator with a Single Gain Segment
We present a ring-type Mamyshev oscillator with only one amplification stage. The design allows self-starting via modulation of the pump power, high pulse performance, and is suitable for all-fiber integration. Â© 2021 OSA.
Integrated sample-handling and mounting system for fixed-Target serial synchrotron crystallography
Serial synchrotron crystallography (SSX) is enabling the efficient use of small crystals for structure-function studies of biomolecules and for drug discovery. An integrated SSX system has been developed comprising ultralow background-scatter sample holders suitable for room and cryogenic temperature crystallographic data collection, a sample-loading station and a humid 'gloveless' glovebox. The sample holders incorporate thin-film supports with a variety of designs optimized for different crystal-loading challenges.
Ice in biomolecular cryocrystallography
Diffraction data acquired from cryocooled protein crystals often include diffraction from ice. Analysis of ice diffraction from crystals of three proteins shows that the ice formed within solvent cavities during rapid cooling is comprised of a stacking-disordered mixture of hexagonal and cubic planes, with the cubic plane fraction increasing with increasing cryoprotectant concentration and increasing cooling rate. Building on the work of Thorn and coworkers [Thorn et al. (2017), Acta Cryst.
Starting dynamics of a linear-cavity femtosecond Mamyshev oscillator
Mamyshev oscillators can generate high-power femtosecond pulses, but starting a mode-locked state has remained a major challenge due to the suppression of continuous-wave lasing. Here, we study the starting dynamics of a linear Mamyshev oscillator designed to generate high-power femtosecond pulses while avoiding component damage. Reliable starting to stable mode-locking is achieved with a combination of modulation of the pump power and shifting of a filter passband. The starting process is automated, with full electronic control.