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Direct protein crystallization on ultrathin membranes for diffraction measurements at X‐ray free‐electron lasers
Author(s) -
Opara Nadia,
Martiel Isabelle,
Arnold Stefan A.,
Braun Thomas,
Stahlberg Henning,
Makita Mikako,
David Christian,
Padeste Celestino
Publication year - 2017
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s1600576717005799
Subject(s) - protein crystallization , femtosecond , diffraction , materials science , beamline , crystallization , nucleation , synchrotron , laser , resolution (logic) , x ray crystallography , crystallography , optics , chemistry , beam (structure) , computer science , physics , organic chemistry , artificial intelligence
A new era of protein crystallography started when X‐ray free‐electron lasers (XFELs) came into operation, as these provide an intense source of X‐rays that facilitates data collection in the `diffract‐before‐destroy' regime. In typical experiments, crystals sequentially delivered to the beam are exposed to X‐rays and destroyed. Therefore, the novel approach of serial crystallography requires thousands of nearly identical samples. Currently applied sample‐delivery methods, in particular liquid jets or drop‐on‐demand systems, suffer from significant sample consumption of the precious crystalline material. Direct protein microcrystal growth by the vapour diffusion technique inside arrays of nanolitre‐sized wells is a method specifically tailored to crystallography at XFELs. The wells, with X‐ray transparent Si 3 N 4 windows as bottoms, are fabricated in silicon chips. Their reduced dimensions can significantly decrease protein specimen consumption. Arrays provide crystalline samples positioned in an ordered way without the need to handle fragile crystals. The nucleation process inside these microfabricated cavities was optimized to provide high membrane coverage and a quasi‐random crystal distribution. Tight sealing of the chips and protection of the crystals from dehydration were achieved, as confirmed by diffraction experiments at a protein crystallography beamline. Finally, the test samples were shown to be suitable for time‐resolved measurements at an XFEL at femtosecond resolution.