1N0Y

Crystal Structure of Pb-bound Calmodulin

Summary for 1N0Y

• Entry DOI: 10.2210/pdb1n0y/pdb
• Descriptor: Calmodulin, LEAD (II) ION, CACODYLATE ION, ... (5 entities in total)
• Functional Keywords: calmodulin, lead, metal binding protein
• Biological source: Paramecium tetraurelia
• Total number of polymer chains: 2
• Total formula weight: 36471.67

Authors

Wilson, M.A.,Brunger, A.T. (deposition date: 2002-10-15, release date: 2003-09-30, Last modification date: 2024-02-14)

Primary citation

Wilson, M.A.,Brunger, A.T.
Domain flexibility in the 1.75 A resolution structure of Pb2+-calmodulin.
Acta Crystallogr.,Sect.D, 59:1782-1792, 2003

PubMed Abstract: Calmodulin (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.

PubMed: 14501118
DOI: 10.1107/S0907444903016846

Experimental method

X-RAY DIFFRACTION (1.75 Å)