title: Directly observed hydrogen bonds at calcium-binding-sites of calmodulin in solution relate to affinity of the calcium-binding.
abstract: Molecular tuning to calcium-binding in the EF-hand motif of holo-calmodulin was studied in solution by NMR (h3)J(NC') H-bond couplings. In the N-terminus lobe of holo-calmodulin, the glutamate crucial for Ca(2+) coordination has network of H-bonds weaker than inferred from the X-ray crystal structure. This glutamate at position 12 appears shifted away from the Ca(2+) preferred coordination, which can explain the lower affinity of the calcium-binding to the N-terminus with respect to C-terminus EF hands.
authors.affiliation: Departments of Biochemistry and Molecular Biology, Mayo College of Medicine, Mayo Clinic and Foundation, Rochester, MN 55905, USA. juranic.nenad@mayo.edu
authors.forename: Nenad
authors.initials: N
authors.lastname: Juranić
authors.forename: Elena
authors.initials: E
authors.lastname: Atanasova
authors.forename: Slobodan
authors.initials: S
authors.lastname: Macura
authors.forename: Franklyn G
authors.initials: FG
authors.lastname: Prendergast
mesh_terms: D000818:Animals; D001665:Binding Sites; D002118:Calcium / Q000737:chemistry* / Q000378:metabolism; D002147:Calmodulin / Q000737:chemistry* / Q000378:metabolism; D018360:Crystallography, X-Ray; D018698:Glutamic Acid / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D006860:Hydrogen Bonding; D011485:Protein Binding / Q000502:physiology; D017433:Protein Structure, Secondary / Q000502:physiology
chemical_list: D002147:Calmodulin; D018698:Glutamic Acid; D002118:Calcium