The class
An (i, i+4) residue array between His466 and Asp470 stabilizes an amphipathic alpha-helix in CETP's C-terminus (Biochim Biophys Acta 1998)
Original title: Stability of the C-terminal peptide of CETP mediated through an (i, i + 4) array
Using circular dichroism, researchers identified an essential (i, i+4) alpha-helix-stabilizing array in the C-terminal region of CETP, spanning histidine 466 to aspartic acid 470, corresponding to an amphipathic alpha-helix. Comparing this peptide's solution behavior to a mutant version (D470N) by dynamic light scattering showed the alpha-helix stabilization was not due to peptide aggregation, and thermodynamic analysis supported an (i, i+4) array mechanism. The findings suggest CETP's lipid-binding activity depends in part on both the asymmetric distribution of polar and nonpolar residues in this C-terminal helix and the (i, i+4) array that stabilizes it.
Original abstract
Based on circular dichroism (CD), we have found an essential (i, i + 4) alpha-helix stabilizing array in the C-terminus region for the cholesteryl ester transfer protein (CETP) between histidine 466 and aspartic acid 470. This region apparently corresponds to an amphipathic alpha-helix. The behavior of this peptide in solution in comparison with a mutant peptide (D470N) was also analyzed by dynamic light scattering (DLS). The results showed that alpha-helix stabilization is not due to peptide aggregation. The thermodynamic estimation of stability supports the idea that the phenomenon is carried out through an (i, i + 4) array. The representation of the C-terminal region as an amphipathic alpha-helical peptide shows that lipid-binding activity might be in part due to both the asymmetric polar/non-polar residue distribution and to the presence of an (i, i + 4) array important for helix stability.
Summary written by cetpinhibition.org from the published abstract; figures as published. Page updated 19 August 2026. Methods.