3URG

The crystal structure of Anabaena CcbP

Summary for 3URG

• Entry DOI: 10.2210/pdb3urg/pdb
• Related: 2P0P 2k2v
• Descriptor: Alr1010 protein, 5-MERCAPTO-2-NITRO-BENZOIC ACID, SODIUM ION, ... (4 entities in total)
• Functional Keywords: calcium binding protein, metal binding protein
• Biological source: Nostoc
• Total number of polymer chains: 1
• Total formula weight: 17161.95

Authors

Fan, X.X.,Liu, X.,Su, X.D. (deposition date: 2011-11-22, release date: 2012-11-28, Last modification date: 2024-03-20)

Primary citation

Fan, X.X.,Zhou, Y.F.,Liu, X.,Li, L.F.,Su, X.D.
Ellman's reagent in promoting crystallization and structure determination of Anabaena CcbP.
Acta Crystallogr.,Sect.F, 68:1409-1414, 2012

PubMed Abstract: Obtaining crystals presented a bottleneck in the structural study of Anabaena cyanobacterial Ca2+-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 Ca2+ binding of CcbP. Thus, DTNB modification may provide a simple and general approach for protein modification to improve the success of crystallization screening.

PubMed: 23143261
DOI: 10.1107/S1744309112034938

Experimental method

X-RAY DIFFRACTION (2.003 Å)