Summary for 3CLN
| Entry DOI | 10.2210/pdb3cln/pdb |
| Descriptor | CALMODULIN, CALCIUM ION (3 entities in total) |
| Functional Keywords | calcium binding protein |
| Biological source | Rattus rattus (black rat) |
| Total number of polymer chains | 1 |
| Total formula weight | 16880.68 |
| Authors | Babu, Y.S.,Bugg, C.E.,Cook, W.J. (deposition date: 1988-05-11, release date: 1988-07-16, Last modification date: 2024-02-21) |
| Primary citation | Babu, Y.S.,Bugg, C.E.,Cook, W.J. Structure of calmodulin refined at 2.2 A resolution. J.Mol.Biol., 204:191-204, 1988 Cited by PubMed Abstract: The crystal structure of mammalian calmodulin has been refined at 2.2 A (1 A = 0.1 nm) resolution using a restrained least-squares method. The final crystallographic R-factor, based on 6685 reflections in the range 2.2 A less than or equal to d less than or equal to 5.0 A with intensities exceeding 2.5 sigma, is 0.175. Bond lengths and bond angles in the molecule have root-mean-square deviations from ideal values of 0.016 A and 1.7 degrees, respectively. The refined model includes residues 5 to 147, four Ca2+ and 69 water molecules per molecule of calmodulin. The electron density for residues 1 to 4 and 148 is poorly defined, and they are not included in the model. The molecule is shaped somewhat like a dumbbell, with an overall length of 65 A; the two lobes are connected by a seven-turn alpha-helix. Prominent secondary structural features include seven alpha-helices, four Ca2+-binding loops, and two short, double-stranded antiparallel beta-sheets between pairs of adjacent Ca2+-binding loops. The four Ca2+-binding domains in calmodulin have a typical EF hand conformation (helix-loop-helix) and are similar to those described in other Ca2+-binding proteins. The X-ray structure determination of calmodulin shows a large hydrophobic cleft in each half of the molecule. These hydrophobic regions probably represent the sites of interaction with many of the pharmacological agents known to bind to calmodulin. PubMed: 3145979DOI: 10.1016/0022-2836(88)90608-0 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2.2 Å) |
Structure validation
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