|
Figure 4.
Figure 4. Stereo diagram of the complex between apo-CaM and
an IQ motif peptide. Two views are shown which are related by a
90° rotation about the horizontal axis. The helical IQ motif
peptide (black, residues Arg654-Ser686) is bent around residue
Tyr675. The N-terminal lobe of CaM (domain I in red, domain II
in yellow) adopts a closed conformation. The C-terminal lobe of
CaM (domain III in cyan, domain IV in blue) adopts a semi-open
conformation. The complex has a rather elongated shape; apo-CaM
forms a channel which surrounds the middle portion of the
peptide. On the other side of the interlobe linker (green),
interactions occur between the two lobes of CaM. Among these
linkages two hydrogen bonds are made across the peptide helix
between the sidechain of residue Glu114 (in ball-and-stick
representation) in linker 3 (purple) and backbone nitrogens of
Glu45 and Ala46 (blue balls) of linker 1.
|
