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Crystal Structure of Pb-bound CalmodulinCrystal Structure of Pb-bound Calmodulin
Structural highlights
Function[CALM_PARTE] Calmodulin mediates the control of a large number of enzymes, ion channels and other proteins by Ca(2+). Among the enzymes to be stimulated by the calmodulin-Ca(2+) complex are a number of protein kinases and phosphatases. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedCalmodulin (CaM) regulates a variety of cellular processes by interacting with a large number of proteins in a Ca(2+)-dependent manner. Conformational flexibility plays a key role in CaM function, although the full extent and detailed features of this flexibility are not fully characterized. Here, the 1.75 A resolution crystal structure of Pb(2+)-bound Paramecium tetraurelia CaM crystallized in a previously unobserved monoclinic lattice is reported. Pb(2+)-CaM is disordered in this new lattice and only a portion of each of the two molecules in the asymmetric unit can be modeled. Comparison of the structures of Ca(2+)-CaM and Pb(2+)-CaM show close agreement in the C-terminal domain but significant structural differences in the N-terminal domain. In addition, translation-libration-screw (TLS) refinement and Rosenfield difference analysis reveal inter-helical flexibility in the metal-bound N-terminal domain of the protein that is absent in the metal-bound C-terminal domain and indicates that the two structurally similar domains of CaM are dynamically distinct. These results demonstrate that TLS refinement and Rosenfield difference analysis allow detailed information about macromolecular flexibility to be extracted from X-ray diffraction data even when the crystal lattice prohibits full manifestation of this flexibility. Domain flexibility in the 1.75 A resolution structure of Pb2+-calmodulin.,Wilson MA, Brunger AT Acta Crystallogr D Biol Crystallogr. 2003 Oct;59(Pt 10):1782-92. Epub 2003, Sep 19. PMID:14501118[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences |
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