ABSTRACT
BL-11C, a new protein crystallography beamline, is an in-vacuum undulator-based microfocus beamline used for macromolecular crystallography at the Pohang Accelerator Laboratory and it was made available to users in June 2017. The beamline is energy tunable in the range 5.0-20â keV to support conventional single- and multi-wavelength anomalous-dispersion experiments against a wide range of heavy metals. At the standard working energy of 12.659â keV, the monochromated beam is focused to 4.1â µm (V) × 8.5â µm (H) full width at half-maximum at the sample position and the measured photon flux is 1.3 × 1012â photonsâ s-1. The experimental station is equipped with a Pilatus3 6M detector, a micro-diffractometer (MD2S) incorporating a multi-axis goniometer, and a robotic sample exchanger (CATS) with a dewar capacity of 90 samples. This beamline is suitable for structural determination of weakly diffracting crystalline substances, such as biomaterials, including protein, nucleic acids and their complexes. In addition, serial crystallography experiments for determining crystal structures at room temperature are possible. Herein, the current beamline characteristics, technical information for users and some recent scientific highlights are described.
Subject(s)
Crystallography, X-Ray/instrumentation , Macromolecular Substances/chemistry , Proteins/chemistry , Carbon Radioisotopes , Equipment Design , Legionella/chemistry , Muramidase/chemistry , Neisseria meningitidis/chemistry , Protein Structural Elements , Synchrotrons , Zymomonas/chemistryABSTRACT
BL-5C is an in-vacuum undulator beamline dedicated to macromolecular crystallography (MX) at the 3â GeV Pohang Light Source II in Korea. The beamline delivers X-ray beams with a focal spot size of 200â µm × 40â µm (FWHM, H × V) over the energy range 6.5-16.5â keV. The measured flux is 7 × 1011â photonsâ s-1 at 12.659â keV through an aperture size of 50â µm. The experimental station is newly equipped with the photon-counting detector EIGER 9M, the multi-axis micro-diffractometer MD2, and a robotic sample changer with a high-capacity dewar. These instruments enable the operation of this beamline as an automated MX beamline specialized in X-ray fragment screening. This beamline can collect more than 400 data sets a day without human intervention, and a difference map can be automatically calculated by using the data processing pipeline for ligand or fragment identification.