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Dynamic structural biology revealed by time-resolved studies, over longer reactions,

with less sample, and including complementary methods

Presented by Allen Orville

X-ray free electron laser (XFEL) sources enable new science, but require novel sample delivery methods. An ideal system will enable scientists to exploit the pulse sequence of the particular source while not wasting sample between XFEL pulses. We developed acoustic droplet ejection (ADE) as a general, touchless, on-demand method that uses focused sound waves to eject picoliter to nanoliter volume droplets from one place to another. In our first applications, we collected serial femtosecond crystallography (SFX) datasets from droplets launched in synchrony to intersect each XFEL pulse (Roessler et al 2016). We have also coupled ADE methods with a conveyor belt drive to enable time-resolved SFX (tr-SFX) at the LCLS. Our system is optimized for crystallography and X-ray emission spectroscopy (XES) measurements of metalloproteins and photochemical reactions over a wide-range of time scales and illumination schemes (Young, Ibrahim, and Chatterjee et al 2016; Fuller and Gull et al 2017). Indeed, the combination of tr-SFX + XES, wherein both types of data are obtained from the same sample and X-ray pulse, provides important complementary information that impacts mechanistic insights. We are also exploiting the region on the belt between the ADE transducer and the X-ray interaction point to introduce additional experimental perturbations that initiate a range of enzyme reactions. I will discuss the potential impact to tr-SFX studies of many macromolecules operating under physiological temperature and pressure. 

Date: 4/19/2017 3:00PM EST

Location: Online via Regular Zoom Meeting access code

See Bill Bauer for details and access code