1DGU: HOMOLOGY-BASED MODEL OF CALCIUM-SATURATED CIB (CALCIUM-AND INTEGRIN-BINDING PROTEIN)

Citation:
Abstract
Calcium- and integrin-binding protein (CIB) binds to the 20-residue alphaIIb cytoplasmic domain of platelet alphaIIbbeta3 integrin. Amino acid sequence similarities with calmodulin (CaM) and calcineurin B (CnB) allowed the construction of homology-based models of calcium-saturated CIB as well as apo-CIB. In addition, the solution structure of the alphaIIb cytoplasmic domain in 45% aqueous trifluoroethanol was solved by conventional two-dimensional NMR methods. The models indicate that the N-terminal domain of CIB possesses a number of positively charged residues in its binding site that could interact with the acidic carboxy-terminal LEEDDEEGE sequence of alphaIIb. The C-terminal domain of CIB seems well-suited to bind the sequence WKVGFFKR, which forms a well-structured alpha helix; this is analogous to calmodulin and calcineurin B, which also bind alpha helices. Similarities between the C-terminal domains of CIB and calmodulin suggest that binding of CIB to the cytoplasmic domain of alphaIIb may be affected by fluctuations in the intracellular calcium concentration.
PDB ID: 1DGUDownload
MMDB ID: 11857
PDB Deposition Date: 1999/11/25
Updated in MMDB: 2007/11
Experimental Method:
solution nmr
Source Organism:
Similar Structures:
Molecular Components in 1DGU
Label Count Molecule
Protein (1 molecule)
1
Calcium-saturated CIB(Gene symbol: CIB1)
Molecule annotation
* Click molecule labels to explore molecular sequence information.

Citing MMDB
.