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Figure 3.
Figure 3. Detailed comparison of the CRC-C/K[19] and
CaM/R[20] complexes (PDB entry codes 1OQP and 1CDL,
respectively). (a) Ribbon representation of the superimposed
structures of CRC-C (blue) and CaM (red) complexes. The overlay
is based on the secondary structural elements in CRC-C and
CaM-C. For clarity, the N-terminal domain of CaM is not
displayed. (b) Comparison of intermolecular contacts between
K[19] and CRC-C to those between R[20] and CaM-C. Residues
within 7 Å are considered to be in contact. The peptides
are aligned on the basis of the common tryptophan residue. The
helical portions of the peptides are drawn in continuous lines,
and the disordered regions in broken lines. Note that two
residues at the N terminus of K[19] and two C-terminal residues
of R[20] have been removed for clarity. The three anchoring
residues in K[19] (Trp10, Leu13, Leu14) and the corresponding
Trp5, Thr8, and Gly9 in R[20] are highlighted in red. The
additional hydrophobic anchor in R[20] (Val12) and the
corresponding residue in K[19] (Asp17) are highlighted in green.
The pseudo numbering scheme used to align the homologous
residues in CRC-C and CaM-C subtracts 92 and 74 from the CRC and
the CaM residue numbers, respectively. Contacts involving
homologous residues in the two complexes are indicated by red
lettering. (c) Overlay of the structures of CRC-C (blue) and
CaM-C (red) from their respective complexes. The side-chains of
methionine and phenylalanine residues in CaM-C and the
corresponding residues in CRC-C are highlighted. The
superposition was made using the backbone heavy atoms of the
helices only. (d) Comparison of the hydrophobic molecular
surfaces (upper panel) and the electrostatic potential surfaces
(lower panel) of CRC-C and CaM-C. The deep hydrophobic pockets
accommodating the tryptophan residues on the surfaces of both
proteins are indicated by the thick arrows. The additional
hydrophobic pocket accommodating Leu13 in K[19] on the surface
of CRC-C is indicated by the wavy arrow. A positively charged
patch unique to CRC-C is indicated by the circle.
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