Comparison of the II/III Interhelical Interface in the Two Domains of Apo Calmodulin

Analysis of the Conformational Differences between Two Domains of Apo Calmodulin: the II/III Interhelical Interface

A comparison of the conformations of the II/III interface in the two domains of apo calmodulin: Interhelical distance difference matrix (DDM) entries are shown in the left panels and interhelical contacts in the two domains of apo CaM are shown in the center (CaM-N) and right (CaM-C) panels. The DDM entries are mapped onto a ribbon representation of apo CaM-N. Residues that are moderately closer together in the CaM-N (DD between -2 and -5 angstroms) are connected by light blue lines. Residues that are moderately closer together in CaM-C (DD between 2 and 5 angstroms) are connected by pink lines. There are no DDs larger than 5 angstroms in magnitude in this interface. Interhelical contacts are categorized on the basis of the centers of geometry (CG) of the respective residues. Close contacts (distance between CGs less than 5 angstroms) are shown as purple lines, mid-range contacts (distance between CGs between 5 and 6.5 angstroms) are shown as blue lines, and long-range contacts (distance between CGs between 6.5 and 8 angstroms) are shown as green lines. Contacts unique to one state are shown as solid lines. Contacts found in both domains are shownas dotted lines. The helices were rendered as ribbons using InsightII (MSI, San Diego, CA), and the DDs and contacts were rendered as distance restraints using the NMR_Refine module of InsightII. PDB coordinates are 1CFC (apo calmodulin) and 1CLL (calcium-loaded calmodulin).

This graphic was figure 6 in the paper:
Nelson, M.R., W.J. Chazin. An Interaction-Based Analysis of Calcium-Induced Conformational Changes in Ca2+ Sensor Proteins (1998) Prot. Sci. 7, 270-282.

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