2RRT

Solution structure of Magnesium-bound form of calmodulin C-domain E104D/E140D mutant

Replaces:  2EQC

Summary for 2RRT

• Entry DOI: 10.2210/pdb2rrt/pdb
• NMR Information: BMRB: 11440
• Descriptor: Calmodulin (1 entity in total)
• Functional Keywords: calmodulin, ef-hand, magnesium, structural genomics, psi, protein structure initiative, riken structural genomics/proteomics initiative, rsgi, metal binding protein, nppsfa, national project on protein structural and functional analyses
• Biological source: Xenopus laevis (clawed frog, common platanna, platanna)
• Total number of polymer chains: 1
• Total formula weight: 8258.97

Authors

Ohashi, W.,Hirota, H.,Yamazaki, T.,RIKEN Structural Genomics/Proteomics Initiative (RSGI) (deposition date: 2011-04-27, release date: 2011-05-25, Last modification date: 2024-05-29)

Primary citation

Ohashi, W.,Hirota, H.,Yamazaki, T.
Solution structure and fluctuation of the Mg(2+)-bound form of calmodulin C-terminal domain
Protein Sci., 20:690-701, 2011

PubMed Abstract: Calmodulin (CaM) is a Ca(2+)-binding protein that functions as a ubiquitous Ca(2+)-signaling molecule, through conformational changes from the "closed" apo conformation to the "open" Ca(2+)-bound conformation. Mg(2+) also binds to CaM and stabilizes its folded structure, but the NMR signals are broadened by slow conformational fluctuations. Using the E104D/E140D mutant, designed to decrease the signal broadening in the presence of Mg(2+) with minimal perturbations of the overall structure, the solution structure of the Mg(2+)-bound form of the CaM C-terminal domain was determined by multidimensional NMR spectroscopy. The Mg(2+)-induced conformational change mainly occurred in EF hand IV, while EF-hand III retained the apo structure. The helix G and helix H sides of the binding sequence undergo conformational changes needed for the Mg(2+) coordination, and thus the helices tilt slightly. The aromatic rings on helix H move to form a new cluster of aromatic rings in the hydrophobic core. Although helix G tilts slightly to the open orientation, the closed conformation is maintained. The fact that the Mg(2+)-induced conformational changes in EF-hand IV and the hydrophobic core are also seen upon Ca(2+) binding suggests that the Ca(2+)-induced conformational changes can be divided into two categories, those specific to Ca(2+) and those common to Ca(2+) and Mg(2+).

PubMed: 21312310
DOI: 10.1002/pro.598

Experimental method

SOLUTION NMR