Time-of-flight Laue Neutron Crystallography at the Protein Crystallography Station (PCS) at LANSCE

CLIFF UNKEFER; JULIAN CHEN; ZOE S. FISHER; JAVIER MARCELO GONZALEZ; JOHN PAUL BACIK; MARYJO WALTMAN

Albuquerque

Congreso; American Crystallographic Association Annual Meeting 2014; 2014

American Crystallographic Association

The PCS at Los Alamos Neutron Science Center is a user facility funded bythe Office of Biological and Environmental Research of the U.S. Departmentof Energy (DOE-OBER). The PCS is a high performance macromolecular neutrondiffractometer built at a spallation neutron source. The PCS utilizesspallation neutrons produced in pulses at 20 Hz for time-of-flightmeasurements by using a wavelength range of 0.6 and 7 Å. This strategyallows for shorter data collection times (7-14 days depending on the spacegroup) and crystal volumes of > 0.4 mm3, making this technique accessibleto more biological problems. The PCS provides full "gene to structure" usersupport: expression and purification of perdeuterated or hydrogenousproteins, crystallization with an Oryx8 robot, assistance with samplehandling and mounting, proposal submission, data collection and processing,as well as computational tools for and help with joint X-ray and neutronstructure refinement. We also now offer in-house X-ray data collection onour Rigaku Highflux X-ray source, facilitating room temperature datacollection used for joint X-ray/neutron refinement. We are working towardsthe design and installation of a second neutron detector and optics tofurther optimize data collection. The run cycle is scheduled to expand to 8months starting in 2015, thus the PCS is looking to expand its user baseand collaborations. The PCS is responsible for nearly half of neutronstructures deposited in the PDB, including a recent ultra-high resolution(1.1 Å) structure of crambin, and the first human drug?protein complex(acetazolamide-carbonic anhydrase).