Interactive H-Bond Histogram

Hydrogen bonds (H-bonds) can be identified with the H-Bonds tool, hbonds command, or the Molecule Display icon and plotted as an interactive histogram with the command crosslinks histogram.

The ChimeraX graphics window shows the complex between a natural killer cell receptor 2B4 and its ligand CD48 (PDB 2ptt). The receptor protein is blue, the ligand protein pink, and H-bonds between them dashed yellow, with H-bonding residues labeled. Although not done here, the H-bonds could also be labeled by distance.

The histogram of H-bond distances on the top right is interactive: when the cursor is placed over a bar in the histogram, the corresponding H-bonds are temporarily enlarged in the 3D view and the others hidden. For image setup other than orientation, see the command file hb3.cxc.

Calmodulin and Target Peptide

Calmodulin (CaM) acts as a calcium sensor. When its four Ca++ sites are fully occupied, it binds and modulates the activity of various downstream proteins, including CaM-dependent protein kinase I (CaMKI). Here, a complex between CaM and its target peptide from CaMKI (PDB 1mxe) is shown with cartoons, a transparent molecular surface, silhouette outlines, and light soft ambient occlusion. (If you prefer a less smudgy/rustic appearance, try using light gentle instead.) For image setup other than positioning, see the command file cam.cxc.

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