First Protein Scattering Measurements at LiX Beamline

Abstract

High Brightness X-ray Scattering for Life Sciences (LiX) is a newly commissioned beamline at the NSLS-II facility of Brookhaven National Laboratory dedicated to three specific scientific areas: 1) high-throughput solution scattering, 2) diffraction from single and multi-layered lipid membranes and 3) scattering based scanning probe imaging. SAXS of macromolecules in solutions has an ever-increasing demand and to better serve user needs, and to allow automated and high-throughput operation, an automated solution scattering setup has been developed at LiX. It consists of two flow-cells, each of this flow-cell picks sample from 6 PCR tube placed in two rows. In future a robot will transfer the holder containing two rows of PCR tube to perform unattended measurements. While the sample is flowed through one of the cell and measured, the second cell is cleaned and dried and made ready for the next set so that an unhindered and continuous set of measurements could be performed. Test measurements were performed on standard set of protein Ribonuclease-A, Hemoglobin, Bovine Serum Albumin (BSA) and β-amylase with molecular weight of 13.7, 64.5, 66.5, 210 KDa respectively. To circumvent X-ray radiation damage, sample is continuously flowed during measurements. Thanks to brilliance of the new source and the optics at the beamline even for relatively small protein molecule Ribonuclease-A at a low concentration of 1mg/ml a 5 sec exposure measurement was good enough to obtain statistically relevant data.