3URG: The Crystal Structure Of Anabaena Ccbp

Acta Crystallogr. Sect. F Struct. Biol. Cryst. Commun. (2012) 68 p.1409-1414
Obtaining crystals presented a bottleneck in the structural study of Anabaena cyanobacterial Ca(2+)-binding protein (CcbP). In this report, the promoting effect of Ellman's reagent [5,5'-dithiobis(2-nitrobenzoic acid); DTNB] on the crystallization of CcbP is described. CcbP contains one free cysteine. A quick and simple oxidation reaction with DTNB blocked the free cysteine in purified CcbP and generated a homogenous monomeric protein for crystallization. The crystal structure of DTNB-modified CcbP was determined by the single-wavelength anomalous diffraction method. Structure analysis indicated that DTNB modification facilitated crystallization of CcbP by inducing polar interactions in the crystal lattice. DTNB-mediated cysteine modification was demonstrated to have little effect on the overall structure and the Ca(2+) binding of CcbP. Thus, DTNB modification may provide a simple and general approach for protein modification to improve the success of crystallization screening.
PDB ID: 3URGDownload
MMDB ID: 105569
PDB Deposition Date: 2011/11/22
Updated in MMDB: 2012/12
Experimental Method:
x-ray diffraction
Resolution: 2  Å
Source Organism:
Similar Structures:
Biological Unit for 3URG: monomeric; determined by author
Molecular Components in 3URG
Label Count Molecule
Protein (1 molecule)
Alr1010 Protein
Molecule annotation
Chemicals (2 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB