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Engineering of the hydrophobic core of an α‐helical coiled coil
Author(s) -
Kiyokawa Tomohiro,
Kanaori Kenji,
Tajima Kunihiko,
Tanaka Toshiki
Publication year - 2000
Publication title -
peptide science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/1097-0282(2000)55:5<407::aid-bip1015>3.0.co;2-y
Subject(s) - heterotrimeric g protein , chemistry , heptad repeat , coiled coil , peptide , peptide sequence , crystallography , stereochemistry , amino acid , biochemistry , receptor , g protein , gene
The amino acid sequence that forms the α‐helical coiled coil structure has a representative heptad repeat denoted by defgabc, according to their positions. Although the a and d positions are usually occupied by hydrophobic residues, hydrophilic residues at these positions sometimes play important roles in natural proteins. We have manipulated a few amino acids at the a and d positions of a de novo designed trimeric coiled coil to confer new functions to the peptides. The IZ peptide, which has four heptad repeats and forms a parallel triple‐stranded coiled coil, has Ile at all of the a and d positions. We show three examples: (1) the substitution of one Ile at either the a or d position with Glu caused the peptide to become pH sensitive; (2) the metal ion induced α‐helical bundles were formed by substitutions with two His residues at the d and a positions for a medium metal ion, and with one Cys residue at the a position for a soft metal ion; and (3) the AAB‐type heterotrimeric α‐helical bundle formation was accomplished by a combination of Ala and Trp residues at the a positions of different peptide chains. Furthermore, we applied these procedures to prepare an ABC‐type heterotrimeric α‐helical bundle and a metal ion‐induced heterotrimeric α‐helical bundle. © 2001 John Wiley & Sons, Inc. Biopolymers (Pept Sci) 55: 407–414, 2000