STOPPED FLOW TIME RESOLVED SAXS DEVELOPMENT

这个子项目是众多研究子项目之一

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Time resolved SAXS is one of the core projects in the BioCAT proposal. Development stopped flow time-resolved SAXS experiments used standard protein (cytochrome c) and RNA samples. The results demonstrate that BioCAT is capable of performing time-resolved SAXS experiments by using the SFM-400 stopped-flow instrument (Bio-Logic) combined with the Aviex CCD in streak camera mode at a time resolution of 4 ms with a reaction dead time of 1.8 ms. For each single mixing event of a sample with a reagent, 16 continuous streak frames can be recorded on the Aviex CCD chip in a single data acquisition, enabling data acquisition over a total time window of 64 ms. Longer time windows may be achieved by using larger exposure times per streak. Sample consumption can be maintained at a low level of ~ 40 ul per mixing event. RNA and protein samples at concentrations as low as ~ 1mg/ml and 5 mg/ml respectively can yield high quality data by averaging the results of 20 data sets. The results of the experiments have been presented in a poster to advertise this technique in the BSR2007 conference in England. In run 2007-3 we tested a Pilatus 100K detector borrowed from the APS detector pool in comparison to the Aviex. The data quality obtained with the Pilatus detector is considerably superior to that obtained with the Aviex detector for framing rates of 200 Hz or slower.