Open AccessImprovement of the quality of lumazine synthase crystals by protein engineering
Author(s) -
RodríguezFernández Lidia,
LópezJaramillo F. Javier,
Bacher Adelbert,
Fischer Markus,
Weinkauf Sevil
Publication year - 2008
Publication title -
acta crystallographica section f
Language(s) - English
Resource type - Journals
ISSN - 1744-3091
DOI - 10.1107/s1744309108015728
Subject(s) - icosahedral symmetry , crystallography , macromolecule , bacillus subtilis , capsid , chemistry , resolution (logic) , low resolution , molecule , crystal structure , space group , diffraction , x ray crystallography , high resolution , physics , biology , biochemistry , optics , genetics , remote sensing , organic chemistry , artificial intelligence , bacteria , gene , computer science , geology
Icosahedral macromolecules have a wide spectrum of potential nanotechnological applications, the success of which relies on the level of accuracy at which the molecular structure is known. Lumazine synthase from Bacillus subtilis forms a 150 Å icosahedral capsid consisting of 60 subunits and crystallizes in space group P 6 3 22 or C 2. However, the quality of these crystals is poor and structural information is only available at 2.4 Å resolution. As classical strategies for growing better diffracting crystals have so far failed, protein engineering has been employed in order to improve the overexpression and purification of the molecule as well as to obtain new crystal forms. Two cysteines were replaced to bypass misfolding problems and a charged surface residue was replaced to force different molecular packings. The mutant protein crystallizes in space group R 3, with unit‐cell parameters a = b = 313.02, c = 365.77 Å, α = β = 90.0, γ = 120°, and diffracts to 1.6 Å resolution.