title: A novel trans conformation of ligand-free calmodulin.
abstract: Calmodulin (CaM) is a highly conserved eukaryotic protein that binds specifically to more than 100 target proteins in response to calcium (Ca(2+)) signal. CaM adopts a considerable degree of structural plasticity to accomplish this physiological role; however, the nature and extent of this plasticity remain to be fully understood. Here, we report the crystal structure of a novel trans conformation of ligand-free CaM where the relative disposition of two lobes of CaM is different, a conformation to-date not reported. While no major structural changes were observed in the independent N- and C-lobes as compared with previously reported structures of Ca(2+)/CaM, the central helix was tilted by ~90° at Arg75. This is the first crystal structure of CaM to show a drastic conformational change in the central helix, and reveals one of several possible conformations of CaM to engage with its binding partner.
authors: Department of Biological Sciences, National University of Singapore, Republic of Singapore, Republic of Singapore.
authors: Veerendra
authors: V
authors: Kumar
authors: Vishnu Priyanka Reddy
authors: VP
authors: Chichili
authors: Xuhua
authors: X
authors: Tang
authors: J
authors: J
authors: Sivaraman
mesh_terms: D001665:Binding Sites; D002118:Calcium / Q000737:chemistry / Q000378:metabolism; D002147:Calmodulin / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D062105:Molecular Docking Simulation; D011485:Protein Binding; D011487:Protein Conformation; D011994:Recombinant Proteins; D015032:Zinc / Q000737:chemistry / Q000378:metabolism
chemical_list: D002147:Calmodulin; D011994:Recombinant Proteins; D015032:Zinc; D002118:Calcium
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