Nanobeam precession-assisted 3D electron diffraction reveals a new polymorph of hen egg-white lysozyme

IUCrJ

Lanza, A.¹ 

[1] Center for Nanotechnology Innovation@NEST, Istituto Italiano di Tecnologia, Piazza San Silvestro 12, 56127 Pisa, Italy

关键词: MACROMOLECULAR CRYSTALLOGRAPHY;    ELECTRON CRYSTALLOGRAPHY;    NANOBEAM PRESSURE-ASSISTED ELECTRON DIFFRACTION;    MONOCLINIC LYSOZYME;    RADIATION DAMAGE;   

DOI  :  10.1107/S2052252518017657

学科分类：数学（综合）

来源: International Union of Crystallography

【 摘 要 】

Recent advances in 3D electron diffraction have allowed the structure determination of several model proteins from submicrometric crystals, the unit-cell parameters and structures of which could be immediately validated by known models previously obtained by X-ray crystallography. Here, the first new protein structure determined by 3D electron diffraction data is presented: a previously unobserved polymorph of hen egg-white lysozyme. This form, with unit-cell parameters a = 31.9, b = 54.4, c = 71.8 Å, β = 98.8°, grows as needle-shaped submicrometric crystals simply by vapor diffusion starting from previously reported crystallization conditions. Remarkably, the data were collected using a low-dose stepwise experimental setup consisting of a precession-assisted nanobeam of ∼150 nm, which has never previously been applied for solving protein structures. The crystal structure was additionally validated using X-ray synchrotron-radiation sources by both powder diffraction and single-crystal micro-diffraction. 3D electron diffraction can be used for the structural characterization of submicrometric macromolecular crystals and is able to identify novel protein polymorphs that are hardly visible in conventional X-ray diffraction experiments. Additionally, the analysis, which was performed on both nanocrystals and microcrystals from the same crystallization drop, suggests that an integrated view from 3D electron diffraction and X-ray microfocus diffraction can be applied to obtain insights into the molecular dynamics during protein crystal growth.

【 授权许可】

CC BY