The copper(II)-binding tripeptide GHK, a valuable crystallization and phasing tag for macromolecular crystallography.

ABSTRACT: The growth of diffraction-quality crystals and experimental phasing remain two of the main bottlenecks in protein crystallography. Here, the high-affinity copper(II)-binding tripeptide GHK was fused to the N-terminus of a GFP variant and an MBP-FG peptide fusion. The GHK tag promoted crystallization, with various residues (His, Asp, His/Pro) from symmetry molecules completing the copper(II) square-pyramidal coordination sphere. Rapid structure determination by copper SAD phasing could be achieved, even at a very low Bijvoet ratio or after significant radiation damage. When collecting highly redundant data at a wavelength close to the copper absorption edge, residual S-atom positions could also be located in log-likelihood-gradient maps and used to improve the phases. The GHK copper SAD met

SUBMITTER: Mehr A 

PROVIDER: S-EPMC7709198 | biostudies-literature | 2020 Dec

REPOSITORIES: biostudies-literature